ADC Therapeutics (ADCT) 6-K 3 Aug 21 2021 Q2 Condensed Consolidated Interim Statement of Operations Financial data

Cover

Cover	6 Months Ended
	Jun. 30, 2021
Cover [Abstract]
Document Type	6-K
Entity File Number	001-39071
Entity Registrant Name	ADC Therapeutics SA
Entity Address, Address Line One	Biopôle
Entity Address, Address Line Two	Route de la Corniche 3B
Entity Address, Postal Zip Code	1066
Entity Address, City or Town	Epalinges
Entity Address, Country	CH
Document Period End Date	Jun. 30, 2021
Entity Central Index Key	0001771910
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2

Condensed Consolidated Interim

Condensed Consolidated Interim Statement of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Profit or loss [abstract]
Revenue	$ 3,760	$ 0	$ 3,760	$ 0
Cost of product sales	(121)	0	(121)	0
Research and development expenses	(39,533)	(25,950)	(78,705)	(61,325)
Selling and marketing expenses	(15,221)	(4,004)	(29,132)	(6,632)
General and administrative expenses	(19,367)	(14,995)	(36,949)	(20,877)
Total operating expense	(74,242)	(44,949)	(144,907)	(88,834)
Loss from operations	(70,482)	(44,949)	(141,147)	(88,834)
Other income (expense)
Other income	199	130	393	278
Convertible loans, derivatives, change in fair value income (expense)	2,053	(79,261)	23,222	(79,261)
Borrowings, Deferred Financing Costs	148	1,571	148	1,571
Share of results with joint venture	(1,169)	0	(1,696)	0
Financial income	15	195	30	569
Financial expense	(2,555)	(897)	(4,555)	(939)
Exchange differences (loss) income	(242)	(100)	152	(71)
Total other (expense) income	(1,847)	(81,504)	17,398	(80,995)
Loss before taxes	(72,329)	(126,453)	(123,749)	(169,829)
Income tax expense	(240)	(104)	(347)	(204)
Net loss	(72,569)	(126,557)	(124,096)	(170,033)
Net loss attributable to:
Owners of the parent	$ (72,569)	$ (126,557)	$ (124,096)	$ (170,033)
Net loss per share
Net loss per share, basic and diluted (in USD per share)	$ (0.95)	$ (2.01)	$ (1.62)	$ (2.97)

Condensed Consolidated Interi_2

Condensed Consolidated Interim Statement of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Profit or loss [abstract]
Net loss	$ (72,569)	$ (126,557)	$ (124,096)	$ (170,033)
Items that may be reclassified to profit and loss
Currency translation differences	20	(13)	56	(215)
Total items that may be reclassified to profit and loss	20	(13)	56	(215)
Other comprehensive income (loss) for the period	20	(13)	56	(215)
Total comprehensive loss for the period	(72,549)	(126,570)	(124,040)	(170,248)
Total comprehensive loss attributable to:
Owners of the parent	$ (72,549)	$ (126,570)	$ (124,040)	$ (170,248)

Condensed Consolidated Interi_3

Condensed Consolidated Interim Balance Sheet - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 371,884	$ 439,195
Trade and other current receivables	2,079	0
Current inventories	7,718	0
Other current assets	12,751	11,255
Total current assets	394,432	450,450
Non-current assets
Property, plant and equipment	3,261	1,629
Right-of-use assets	8,077	3,129
Intangible assets	12,010	10,179
Interest in joint venture	46,212	47,908
Other long-term assets	394	397
Total non-current assets	69,954	63,242
Total assets	464,386	513,692
Current liabilities
Accounts payable	14,631	5,279
Other current liabilities	29,450	30,375
Lease liabilities, short-term	988	1,002
Current income tax payable	237	149
Convertible loans, short-term	6,193	3,631
Total current liabilities	51,499	40,436
Non-current liabilities
Convertible loans, long-term	84,648	34,775
Convertible loans, derivatives	49,619	73,208
Deferred gain of joint venture	23,539	23,539
Lease liabilities, long-term	7,612	2,465
Defined benefit pension liabilities	3,551	3,543
Other non-current liabilities	0	221
Total non-current liabilities	168,969	137,751
Total liabilities	220,468	178,187
Equity attributable to owners of the parent
Share capital	6,445	6,314
Share premium	981,290	981,056
Treasury shares	(134)	(4)
Other reserves	74,971	42,753
Cumulative translation adjustments	301	245
Accumulated losses	(818,955)	(694,859)
Total equity attributable to owners of the parent	243,918	335,505
Total liabilities and equity	$ 464,386	$ 513,692

Condensed Consolidated Interi_4

Condensed Consolidated Interim Statement of Changes in Equity - USD ($) $ in Thousands	Total	Share Capital	Share Premium	Other Reserves	Treasury Shares	Cumulative Translation Adjustments	Accumulated Losses
Equity, beginning balance at Dec. 31, 2019	$ 111,156	$ 4,361	$ 549,922	$ 5,473	$ (100)	$ 69	$ (448,569)
Loss for the period	(170,033)						(170,033)
Translation adjustment	(215)					(215)
Other comprehensive income (loss) for the period	(215)					(215)
Total comprehensive loss for the period	(170,248)					(215)	(170,033)
Share-based compensation expense	11,181			11,181
Total transactions with owners	255,394	1,434	242,683	11,181	96
Equity, ending balance at Jun. 30, 2020	196,302	5,795	792,605	16,654	(4)	(146)	(618,602)
Increase (Decrease) Through Shares Surrendered To Redeem Share Purchase Plan Promissory Notes	0		11,208		(11,208)
Issue Of Equity Through Capitalization Of Reserves	0	393	(393)
Increase (decrease) through treasury share transactions, equity	0	34			(34)
Increase (Decrease) Through Issuance To Settle Incentive Plan Awards	0		(29)		29
Issue Of Equity Through Initial Public Offering	232,668	1,007	231,661
Issue Of Equity Through Over-allotment Option	34,900		23,591		11,309
Share Issue Related Cost Through Initial Public Offering And Over-Allotment Option	(23,355)		(23,355)
Equity, beginning balance at Mar. 31, 2020	71,268	4,361	549,922	9,263	(100)	(133)	(492,045)
Loss for the period	(126,557)						(126,557)
Translation adjustment	(13)					(13)
Other comprehensive income (loss) for the period	(13)					(13)
Total comprehensive loss for the period	(126,570)					(13)	(126,557)
Share-based compensation expense	7,391			7,391
Total transactions with owners	251,604	1,434	242,683	7,391	96
Equity, ending balance at Jun. 30, 2020	196,302	5,795	792,605	16,654	(4)	(146)	(618,602)
Increase (Decrease) Through Shares Surrendered To Redeem Share Purchase Plan Promissory Notes	0		11,208		(11,208)
Issue Of Equity Through Capitalization Of Reserves	0	393	(393)
Increase (decrease) through treasury share transactions, equity	0	34			(34)
Increase (Decrease) Through Issuance To Settle Incentive Plan Awards	0		(29)		29
Issue Of Equity Through Initial Public Offering	232,668	1,007	231,661
Issue Of Equity Through Over-allotment Option	34,900		23,591		11,309
Share Issue Related Cost Through Initial Public Offering And Over-Allotment Option	(23,355)		(23,355)
Equity, beginning balance at Dec. 31, 2020	335,505	6,314	981,056	42,753	(4)	245	(694,859)
Loss for the period	(124,096)						(124,096)
Translation adjustment	56					56
Other comprehensive income (loss) for the period	56					56
Total comprehensive loss for the period	(124,040)					56	(124,096)
Exercise of options	235		234		1
Share-based compensation expense	32,218			32,218
Total transactions with owners	32,453		234	32,218
Equity, ending balance at Jun. 30, 2021	243,918	6,445	981,290	74,971	(134)	301	(818,955)
Increase (decrease) through treasury share transactions, equity	0				(131)
Equity, beginning balance at Mar. 31, 2021	297,968	6,314	981,059	56,704	(4)	281	(746,386)
Loss for the period	(72,569)						(72,569)
Translation adjustment	20					20
Other comprehensive income (loss) for the period	20					20
Total comprehensive loss for the period	(72,549)					20	(72,569)
Exercise of options	232		231		1
Share-based compensation expense	18,267			18,267
Total transactions with owners	18,499	131	231	18,267	(130)
Equity, ending balance at Jun. 30, 2021	$ 243,918	6,445	$ 981,290	$ 74,971	$ (134)	$ 301	$ (818,955)
Increase (decrease) through treasury share transactions, equity		$ 131

Condensed Consolidated Interi_5

Condensed Consolidated Interim Statement of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash used in operating activities
Loss for the period	$ (124,096)	$ (170,033)
Adjustments for non-monetary items:
Share-based compensation expense	32,218	11,181
Depreciation of property, plant and equipment	351	294
Amortization of intangible assets	63	17
Depreciation of right-of-use assets	799	569
Gain from reversal of inventory impairment charges	(6,752)	0
Share of results with joint venture	1,696	0
Change in defined benefit pension liability	165	189
Convertible loans, derivatives, (increase) decrease in fair value	(23,222)	79,261
Financial income	(30)	(569)
Financial expense	4,441	868
Exchange differences	(251)	0
Income taxes	347	204
Operating loss before working capital changes	(114,271)	(78,019)
Increase in accounts receivable, net	(2,079)	0
Increase in other assets	(966)	0
Increase in other assets	(1,636)	(3,569)
Increase in accounts payable	8,982	3,468
(Decrease) increase in other liabilities	(1,156)	4,781
Cash used in operating activities	(111,126)	(73,339)
Interest paid	(2,070)	(61)
Interest received	22	588
Interest expense on lease obligations	114	61
Tax refund (paid)	(99)	2
Net cash used in operating activities	(113,159)	(72,749)
Cash used in investing activities
Payment for purchase of property, plant and equipment	(1,605)	(226)
Payment for purchase of intangible assets	(1,900)	(408)
Net cash used in investing activities	(3,505)	(634)
Cash from financing activities
Proceeds from public offering of common shares, net of transaction costs	0	244,213
Proceeds from convertible loans, net of transaction costs	49,591	62,896
Proceeds from the exercise of stock options	234	0
Principal portion of lease obligation payments	(517)	(554)
Net cash from financing activities	49,308	306,555
Net decrease in cash and cash equivalents	(67,356)	233,172
Exchange gain / (losses) on cash and cash equivalents	45	(130)
Cash and cash equivalents at beginning of the period	439,195	115,551
Cash and cash equivalents at end of the period	371,884	348,593
Supplemental Non-Cash Investing Information
Capital expenditures recorded in Accounts payable	$ 367	$ 0

Corporate information

Corporate information	6 Months Ended
	Jun. 30, 2021
Corporate Information And Statement Of IFRS Compliance [Abstract]
Corporate information	Corporate information ADC Therapeutics SA (the “Company” or “ADCT”) was incorporated on June 6, 2011 under the laws of Switzerland. The registered office of the Company is located at Route de la Corniche 3B, 1066 Epalinges, Switzerland. The Company controls two wholly-owned subsidiaries: ADC Therapeutics America, Inc. (“ADCT America”), which was incorporated in Delaware, USA on December 10, 2014, and ADC Therapeutics (UK) Ltd (“ADCT UK”), which was incorporated in England on December 12, 2014. The Company and its two subsidiaries form the ADCT Group (the “Group”). The Group is focused on the development of antibody drug conjugates (“ADCs”), including research, development, human clinical trials, regulatory approval and commercialization. On April 23, 2021, the U.S. Food and Drug Administration (“FDA”) approved ZYNLONTA for the treatment of relapsed or refractory diffuse large B-cell lymphoma (“DLBCL”) and the Company commenced recognizing revenue upon the sale of ZYNLONTA during the second quarter of 2021. ADCs are drug constructs which combine monoclonal antibodies specific to particular types of cells with cytotoxic molecules or warheads which seek to kill any cancer cell to which the ADC attaches. ADCs have extensive potential therapeutic applications in cancer. These unaudited condensed consolidated interim financial statements were authorized for issue by the Board of Directors on August 3, 2021. Going concern basis ADCT is a commercial-stage company developing innovative therapeutics. The Group is exposed to all risks inherent in establishing and developing its business, including the substantial uncertainty that current projects will succeed. The Group’s success may also depend on its ability to: • establish and maintain a strong patent position and protection; • develop, gain regulatory approval and commercialize drug products; • enter into collaborations with partners in the pharmaceutical industry; • acquire and retain key personnel; and • acquire additional funding to support its operations. Since its incorporation, the Group has primarily funded its growth through capital increases and additional funds provided by research collaborations and issuance of the Company’s common shares and the issuance of convertible loans (see note 13, “Convertible loans”). The Group does not have recourse to bank loans. As a result, the Group is not exposed to liquidity risk through requests for early repayment of loans, other than, pursuant to the convertible loans, it must maintain a balance of at least USD 50 million in cash and cash equivalents at the end of each quarter. As of June 30, 2021, the Group’s cash and cash equivalents amounted to USD 371.9 million (December 31, 2020: USD 439.2 million). Management believes that the Group has sufficient financial resources to cover its operating costs for at least the next 12 months from the date of issuance of these unaudited condensed consolidated interim financial statements and, as a result, is presenting these unaudited condensed consolidated interim financial statements of the Group on a going concern basis. COVID – 19 The COVID-19 pandemic has negatively impacted the economies of most countries around the world. The Group’s operations, similar to those of other life sciences companies, have been impacted by the COVID-19 pandemic. The Group is in close contact with its principal investigators and clinical sites, which are located in jurisdictions affected by the COVID-19 pandemic, and is assessing the impact of the COVID-19 pandemic on its clinical trials, expected timelines and costs on an ongoing basis. The Group is commercializing ZYNLONTA using hybrid launch plans formulated to mitigate the impact of the COVID-19 pandemic, including by engaging physicians virtually as well as face-to-face. In response to the spread of COVID-19, the Group has also modified its business practices, including restricting employee travel, developing social distancing plans for its employees and cancelling physical participation in meetings, events and

Basis of preparation

Basis of preparation	6 Months Ended
	Jun. 30, 2021
Corporate Information And Statement Of IFRS Compliance [Abstract]
Basis of preparation	Basis of preparation Statement of Compliance These unaudited condensed consolidated interim financial statements as of and for the three and six months ended June 30, 2021 have been prepared in accordance with International Accounting Standard 34 Interim Financial Reporting (“IAS 34”) and should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2020. Functional and reporting currency These unaudited condensed consolidated interim financial statements are presented in United States Dollars (“USD” or “$”), which is the Company’s functional currency and the Group’s reporting currency. A subsidiary of the Company, ADCT UK, has a functional currency of the British Pound (“GBP”). The following exchange rates have been used for the translation of the financial statements of ADCT UK: Six Months Ended June 30, 2021 2020 USD / GBP Closing rate, GBP 1 1.38358 1.23272 Weighted average exchange rate, GBP 1 1.39134 1.23277 Basis of Consolidation The unaudited condensed consolidated interim financial statements incorporate the financial statements of the Company and entities controlled by the Company. Control is achieved where the Company has the power to govern the financial and operating policies of an entity so as to obtain benefits from its activities. In addition, the Company acquired a 49% equity interest in Overland ADCT BioPharma (CY) Limited (“Overland ADCT BioPharma”) during December 2020 which the Company accounts for under the equity method of accounting (see note 11, “Interest in Joint Venture”). The consolidated entities include: Ownership Interest June 30, 2021 June 30, 2020 ADCT America 100 % 100 % ADCT UK 100 % 100 % Use of estimates and judgements The preparation of the unaudited condensed consolidated interim financial statements in conformity with IAS 34 requires management to make judgements, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets and liabilities, income and expense. Actual results may differ from these estimates. Estimates are based on management’s knowledge of current events and actions that the Company may undertake in the future. Estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period in which the estimate is revised if the revision affects only that period, or in the period of the revision and future periods if the revision affects both current and future periods. In preparing these unaudited condensed consolidated interim financial statements, the significant judgements made by management in applying the Group’s accounting policies and the key sources of estimation uncertainty included those that applied to the consolidated financial statements for the year ended December 31, 2020. In addition, significant judgements were required in implementing the Company’s revenue recognition accounting policy as set out in note 3, “Significant accounting policies”. In particular, significant judgement was required in determining the Company’s gross-to-net (“GTN”) sales adjustments and reversals of previously recorded impairment charges related to inventory costs. Selling and marketing ( “ S&M ” ) expenses S&M expenses relate to the build-out of the commercial organization as the Company prepared for the launch of ZYNLONTA (formerly known as loncastuximab tesirine or Lonca). Prior to December 31, 2020, S&M expenses were reported within General and administrative (“G&A”) expenses within the unaudited condensed consolidated interim statement of operations. The unaudited condensed consolidated interim statement of operations and notes thereto for the period ended June 30, 2020 have been recast to conform S&M expenses to the current period presentation. The Company began presenting S&M expenses for the year ended December 31, 2020 in the Company’s annual report on Form 20-F. Share Subscription Agreement During the second quarter of 2021, ADCT issued 1,500,000 common shares to ADCT America pursuant to a share subscription agreement and immediately repurchased these shares to hold as treasury shares. As of June 30, 2021, the Company held 1,548,303 treasury shares. Open Market Sale Agreement On June 4, 2021, the Company entered into an open market sale agreement with Jefferies LLC (“Jefferies”), to sell its common shares from time to time through an “at the market” offering program (the “ATM Facility”). The ATM Facility provides the Company the opportunity to sell its common shares with an aggregate offering price of up to USD 200.0 million. For the quarter ended June 30, 2021, there have been no shares sold under the ATM Facility. The Company capitalizes transaction costs within Other current assets in the Company’s unaudited condensed consolidated interim balance sheet when costs are incurred associated with the ATM Facility at inception and if and when shares are sold under the ATM Facility in the future. If and when the Company sells shares under the ATM, capitalized transaction costs will be offset against the sale proceeds and will be recorded as a reduction of share premium within the Company’s unaudited condensed consolidated interim balance sheet. At the end of each quarter, if the Company determines that it is not probable that shares will be sold under the ATM Facility by the end of a quarter, the Company will write-off capitalized transaction costs incurred during that respective quarter in the unaudited condensed consolidated interim statement of operations. The Company capitalized KUSD 149 of transaction costs within Other current assets in connection with the establishment of the ATM Facility as of June 30, 2021, which will be offset against the sales proceeds from the initial sale of shares under the ATM Facility, when such sale is to occur.

Significant accounting policies

Significant accounting policies	6 Months Ended
	Jun. 30, 2021
Accounting Policies, Changes in Accounting Estimates And Errors [Abstract]
Significant accounting policies	Significant accounting policiesThe accounting policies applied by the Company in these unaudited condensed consolidated interim financial statements are the same as those applied by the Company in its audited consolidated financial statements as of and for the year ended December 31, 2020 and have been applied consistently to all periods presented in these unaudited condensed consolidated interim financial statements, except for the following: Revenue Recognition Upon the April 23, 2021 FDA approval of ZYNLONTA for the treatment of relapsed or refractory DLBCL, the Company began generating revenue from the sale of its product candidates. In previous years, the Company had generated only service revenues from a license and collaboration arrangement. Revenue from the sale of products is recognized in a manner that depicts the transfer of those promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for these goods or services. To achieve this core principle, the Company follows a five-step model: (i) identify the customer contract; (ii) identify the contract’s performance obligation; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations; and (v) recognize revenue when, or as, a performance obligation is satisfied. Revenue is also reduced for GTN sales adjustments, which may include government rebates, chargebacks, distributor service fees, other rebates and administrative fees, sales returns and allowances and sales discounts. GTN sales adjustments involve significant estimates and judgment after considering factors including legal interpretations of applicable laws and regulations, historical experience and drug product analogs in the absence of Company experience, payer channel mix, current contract prices under applicable programs, unbilled claims and processing time lags and inventory levels in the distribution channel. The Company also uses information from external sources to identify prescription trends, patient demand, average selling prices and sales return and allowance data for analog drug products. The Company’s estimates are subject to inherent limitations of estimates that rely on third-party information, as certain third-party information was itself in the form of estimates, and reflect other limitations including lags between the date as of which third-party information is generated and the date on which the Company receives third-party information. Estimates will be assessed each period and adjusted as required to revise information or actual experience. Cost of product sales Cost of product sales primarily includes direct and indirect costs relating to the manufacture of ZYNLONTA from third-party providers of manufacturing, distribution and logistics, intangible asset amortization expense, and royalties to a collaboration partner based on net product sales of ZYNLONTA. Inventory amounts written down as a result of excess or obsolescence are charged to Cost of product sales. Accounts Receivable Accounts receivable arise from product sales and consists of amounts due from customers, net of customer allowances for chargebacks, product returns and estimated credit losses. Upon the launch of ZYNLONTA, the Company’s contracts with customers have initial payment terms that range from 30 to 150 days. When determining customer allowances for estimated credit losses, the Company analyzes accounts that are past due, the creditworthiness of its customers, current economic conditions and, when sufficient historical data becomes available, actual credit losses incurred by the Company. As of June 30, 2021, the Company determined an allowance for expected credit losses was not required based upon the assessment performed. Inventory Prior to receiving FDA approval of ZYNLONTA, the Company had written down inventory costs relating to the manufacture of ZYNLONTA to a net realizable value of zero. The Company believed that capitalization of inventory costs associated with certain products prior to regulatory approval of such products, or for inventory produced in new production facilities, was only appropriate when management considered it highly probable that pre-approval inventory costs would be recoverable through future sales of the drug product. The determination to capitalize was based on the particular facts and circumstances related to the expected regulatory approval of the product or production facility being considered and, accordingly, the time frame within which the determination was made varied from product to product. The impairment charges were recorded as Research and development (“R&D”) expenses in the Company’s condensed consolidated interim statement of operations. Upon the receipt of FDA approval for ZYNLONTA, the Company reversed KUSD 6,752 of previously recorded impairment charges based on a number of factors existing at that time, including the existence of inventory on hand and estimated demand, as well as expiration dating. The reversal of impairment charges was recorded as a gain to R&D expenses in the Company’s unaudited condensed consolidated interim statement of operations. The amount of the impairment reversal may increase in future periods based on future enhancements that may extend the shelf life of the components used to manufacture ZYNLONTA and/or of the ultimate drug product. Inventory of ZYNLONTA is stated at the lower of cost or net realizable value with costs determined on a first-in, first-out basis. The Company assesses the recoverability of capitalized inventory during each reporting period and will write down excess or obsolete inventory to its net realizable value in the period in which the impairment is identified within Cost of product sales in the unaudited condensed consolidated interim statement of operations. The Company has not recorded any material inventory impairments since the FDA approved ZYNLONTA. Included in inventory are materials used in the production of preclinical and clinical products, which are charged to R&D expenses when consumed. The Company will continue to assess the likelihood that inventory costs associated with its other drug product candidates are recoverable through future sales of such product candidates to determine if and when such costs should be capitalized as inventory or be expensed to R&D expenses. The assessment of whether or not the product is considered highly probable to be saleable will be made on a quarterly basis and includes, but is not limited to, how far a particular product or facility has progressed along the approval process, any known safety or efficacy concerns, potential labeling restrictions and other impediments. If it is determined that inventory costs associated with a product candidate are not highly probable to be recovered through future sales, the Company would record such costs to R&D expenses. Intangible assets Licenses Licenses acquired are capitalized as intangible assets at historical cost. Licenses with definite useful lives are amortized over their useful lives, which are determined on a basis of the expected pattern of consumption of the expected future economic benefits embodied in the licenses and which therefore commence only once the necessary regulatory and marketing approvals have been received. Prior to regulatory and marketing approval, licenses are treated as indefinite-lived assets and not amortized. These licenses are tested annually for impairment in the last quarter of each fiscal year and more frequently if events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. Amortization and impairment of licenses Prior to regulatory and marketing approval, impairment of indefinite-lived licenses is charged to R&D expenses. Subsequent to regulatory and marketing approval, amortization of licenses will be charged to Cost of product sales over the licenses’ estimated useful lives. The useful life of definite-lived intangible assets will depend upon the legal term of the individual patent in the country in which the patent is obtained. In determining the useful life, the Company utilizes the last-to-expire period of exclusivity (primary patent or regulatory approval) related to the primary marketed drug product. The Company may be able to obtain a patent term extension. However, the Company will only consider the inclusion of an extension period to the extent the Company believes it is highly probable of being granted. See note 10, “Intangible assets” for further information. New and amended IFRS standards There are no new IFRS standards, amendments to standards or interpretations that are mandatory for the financial year beginning on January 1, 2021, that are relevant to the Group and that have had any impact in the interim period. New standards, amendments to standards and interpretations that are not yet effective, which have been deemed by the Group as currently not relevant, are not listed here. Income tax expense Taxes on income in the interim periods are accrued using the tax rate that would be applicable to expected total annual profit or loss.

Financial risk management

Financial risk management	6 Months Ended
	Jun. 30, 2021
Financial Instruments [Abstract]
Financial risk management	Financial risk management 4.1 Financial risk factors The Group’s activities are exposed to a variety of financial risks: market risk (including changes in the Company’s share price, exposure to fluctuation in currency exchange rates and exposure to interest rate movements), credit risk and liquidity risk. The unaudited condensed consolidated interim financial statements do not include all financial risk management information and disclosures required in the annual financial statements, and should be read in conjunction with the Group’s consolidated financial statements as of December 31, 2020. There have been no material changes in financial risk management since year-end. 4.2 Fair value estimation At June 30, 2021, the carrying amount is a reasonable approximation of fair value for the following financial assets and liabilities: • Cash and cash equivalents • Trade accounts receivable • Trade accounts payable In the six months ended June 30, 2021, there were no significant changes in the business or economic circumstances that affected the fair value of the Group’s financial assets and financial liabilities. Fair values must be estimated at each grant date with regard to awards under the ADC Therapeutics SA 2019 Equity Incentive Plan (the “Equity Incentive Plan 2019”) and with regard to the convertible loan conversion option derivative related to the first tranche and second tranche of the convertible loans. The approach to valuation follows the grant date fair value principle, and the key input factors are described for the share-based compensation awards in note 14, “Share-based compensation” and for the convertible loan derivatives in note 13, “Convertible loans”. Commonly accepted pricing models (Hull and Goldman Sachs) have been used to calculate the fair value of the convertible loan derivatives. The valuation of the embedded derivative in the first tranche and second tranche are classified as pertaining to level 3 of the valuation hierarchy set out below. The different levels of the valuation hierarchy have been defined as follows: (a) Level 1: quoted prices (unadjusted) in active markets for identical assets or liabilities; (b) Level 2: inputs other than quoted prices that are observable for the asset or liability, either directly (for example, as prices) or indirectly (for example, derived from prices); (c) Level 3: inputs for the asset or liability that are not based on observable market data. There were no transfers between the respective levels during the period. The embedded derivative conversion feature associated with the first and second tranche of the Company’s convertible loans (see note 13, “Convertible loans”) are re-measured to fair value at each reporting date. The Company utilizes a risk free rate, an implied bond yield and a selected volatility in determining the fair value of its embedded derivatives. A hypothetical 10% increase (decrease) in the risk free rate as of June 30, 2021 would have increased (decreased) the derivative value associated with the first tranche of our convertible loans by KUSD 17 and (KUSD 17). A hypothetical 10% increase (decrease) in the implied bond yield as of June 30, 2021 would have increased (decreased) the derivative value associated with the first tranche of our convertible loans by KUSD 295 and (KUSD 307). A hypothetical 10% increase (decrease) in the selected volatility as of June 30, 2021 would have increased (decreased) the derivative value associated with the first tranche of our convertible loans by KUSD 1,248 and (KUSD 1,737). A hypothetical 10% increase (decrease) in the risk free rate as of June 30, 2021 would have increased (decreased) the derivative value associated with the second tranche of our convertible loans by KUSD 14 and (KUSD 14). A hypothetical 10% increase (decrease) in the implied bond yield as of June 30, 2021 would have increased (decreased) the derivative value associated with the second tranche of our convertible loans by KUSD 171 and (KUSD 178). A hypothetical 10% increase (decrease) in the selected volatility as of June 30, 2021 would have increased (decreased) the derivative value associated with the second tranche of our convertible loans by KUSD 1,089 and (KUSD 1,385).

Product revenues, net

Product revenues, net	6 Months Ended
	Jun. 30, 2021
Revenue From Contracts With Customers [Abstract]
Product revenue, net	Product revenues, netOn April 23, 2021, the Company received FDA accelerated regulatory and marketing approval for ZYNLONTA and launched in the U.S. shortly thereafter. To date, the Company’s only source of product revenue, which commenced during May 2021, has been sales of ZYNLONTA. Product revenues, net were KUSD 3,760 for both the three and six months ended June 30, 2021. The Company records its best estimate of GTN sales adjustments to which customers are likely to be entitled. See note 3, “Significant accounting policies” for further information. The table below provides a rollforward of the Company’s GTN sales adjustments for the six months ended June 30, 2021. (in KUSD) Total Beginning balance at January 1, 2021 — GTN sales adjustments related to sales in the current period 752 Credits and payments made (22) Ending balance as of June 30, 2021 730 The table below provides the classification of the GTN sales adjustment included in the Company’s unaudited condensed consolidated interim balance sheet as of June 30, 2021. (in KUSD) As of June 30, 2021 Accounts receivable, net 533 Other current liabilities 197

Segment information

Segment information	6 Months Ended
	Jun. 30, 2021
Operating Segments [Abstract]
Segment information	Segment informationThe Company is managed and operated as one business. A single management team that reports to the chief executive officer comprehensively manages the entire business. Accordingly, the Company views its business and manages its operations as one operating segment.

Expenses by nature

Expenses by nature	6 Months Ended
	Jun. 30, 2021
Analysis of income and expense [abstract]
Expenses by nature	Expenses by nature The following table summarizes R&D expenses, S&M expenses and G&A expenses for the three and six months ended June 30, 2021 and 2020: (in KUSD) Three months ended June 30, Six months ended June 30, R&D 2021 2020 2021 2020 External costs (1) 21,983 16,161 46,289 42,300 Employee expense (2) 17,550 9,789 32,416 19,025 R&D expenses 39,533 25,950 78,705 61,325 S&M External costs 5,726 2,105 11,016 3,845 Employee expense (2) 9,495 1,899 18,116 2,787 S&M expenses 15,221 4,004 29,132 6,632 G&A External costs (1) 5,872 2,316 10,605 4,556 Employee expense (2) 13,495 12,679 26,344 16,321 G&A expenses 19,367 14,995 36,949 20,877 (1) Includes depreciation expense (2) Includes share-based compensation expense The increase in R&D expenses in the three and six months ended June 30, 2021 was primarily associated with the increased number of R&D employees necessary to advance the Company's lead product candidates, which also contributed to increased share-based compensation expense. The increase in R&D expense in the three and six months ended June 30, 2021 was also due to higher expense associated with an increase in clinical trial activity as well as higher chemistry, manufacturing and controls (“CMC”) expenses due to the launch of ZYNLONTA. As a result of FDA approval of ZYNLONTA, during the three and six months ended June 30, 2021, the Company reversed KUSD 6,752 of previously recorded impairment charges relating to inventory costs incurred for the manufacture of product prior to FDA approval. See note 3, “Significant accounting policies” for further information. The increase in S&M expenses in the three and six months ended June 30, 2021 was primarily due to the increased number of employees necessary to prepare for the launch of ZYNLONTA, which also contributed to higher share-based compensation expense. Also contributing to the increase in S&M expenses in the three and six months ended June 30, 2021 were higher professional fees for the launch of ZYNLONTA.

Cash and cash equivalents

Cash and cash equivalents	6 Months Ended
	Jun. 30, 2021
Cash and cash equivalents [abstract]
Cash and cash equivalents	Cash and cash equivalentsPursuant to the Facility Agreement entered into on April 24, 2020 (see note 13, “Convertible loans”), the Company is subject to a covenant that requires it to maintain a balance of at least USD 50 million in cash and cash equivalents at the end of each quarter, and such amounts are included in cash and cash equivalents on the unaudited condensed consolidated interim balance sheet.

Inventories

Inventories	6 Months Ended
	Jun. 30, 2021
Inventory [Abstract]
Disclosure of inventories [text block]	Inventory Inventory as of June 30, 2021 consisted of the following: (in KUSD) As of June 30, 2021 Raw materials — Work in process 7,411 Finished goods (1) 307 Total inventory 7,718 (1) Finished goods includes KUSD 9 relating to ZYNLONTA held on consignment by the Company’s third-party logistics and distribution provider. The Company did not capitalize inventory costs as of December 31, 2020. See note 3, “Significant accounting policies” for further information.

Intangible assets

Intangible assets	6 Months Ended
	Jun. 30, 2021
Intangible Assets [Abstract]
Intangible assets	Intangible assets Licenses classified as definite-lived intangible assets are amortized over their useful lives, which are determined on the basis of the expected pattern of consumption of the expected future economic benefits embodied in the licenses and which therefore commence only once the necessary regulatory and marketing approval has been received for the product candidates to which they relate. The Company classifies its licenses relating to product candidates for which regulatory approval has not been received as indefinite-lived intangible assets and did not recognize amortization expense relating to these licenses. On April 23, 2021, the Company received FDA approval for ZYNLONTA. Upon FDA approval, the Company assigned an estimated useful life of 14 years to the intangible assets related to ZYNLONTA based on the expected patent life, which includes an extension period that the Company believes is highly probable of being granted. This estimated useful life does not include additional patent protection that may be granted under applications filed but not yet approved other than the extension period discussed above. Amortization expense relating to the ZYNLONTA intangible assets for both the three and six months ended June 30, 2021 was KUSD 13, which was recorded in Cost of product sales in the unaudited condensed consolidated interim statement of operations. During the six months ended June 30, 2021, the Company capitalized the following as intangible assets: Milestone Payments • An amount of KUSD 1,050 paid upon the successful completion of a pre-clinical toxicology study and IND submission related to an antibody the Company acquired from a third party to be used in research, development, manufacturing and commercialization. The amount was capitalized as an indefinite-lived intangible asset; and • An amount of KUSD 600 paid upon final regulatory approval of ZYNLONTA related to a license agreement with a third party to use their technology to research, develop, manufacture and commercialize products. The amount was capitalized as a definite-lived intangible asset and will be amortized over its estimated useful life of 14 years as described above. License Payments • An amount of KUSD 250 paid relating to a license agreement with a third party to acquire an antibody to be used in research, development, manufacturing and commercialization. The amount was capitalized as an indefinite-lived intangible asset. During the six months ended June 30, 2020, the Company capitalized the following as intangible assets: Milestone Payments • An amount of KUSD 250 paid upon the successful completion of a toxicology study related to an antibody the Company acquired from a third party to be used in research, development, manufacturing and commercialization. The amount was capitalized as an indefinite-lived intangible asset. License Payments • An amount of KUSD 125 paid relating to license agreements with a third party to use their technology to generate antibody-drug conjugates for up to five antibodies. The table below provides a rollforward of the Company’s intangible assets as of June 30, 2021 and 2020. (in KUSD) Cost Licenses - indefinite lived Licenses - definite lived Software Total January 1, 2021 11,144 — 168 11,312 Additions 1,300 600 — 1,900 Transfers (452) 452 (6) (6) June 30, 2021 11,992 1,052 162 13,206 Accumulated Amortization January 1, 2021 (1,069) — (64) (1,133) Amortization charge — (13) (50) (63) June 30, 2021 (1,069) (13) (114) (1,196) Net book amount as of June 30, 2021 10,923 1,039 48 12,010 Cost January 1, 2020 9,221 — 147 9,368 Additions 375 — 33 408 Exchange differences — — (3) (3) June 30, 2020 9,596 — 177 9,773 Accumulated Amortization January 1, 2020 (853) — (81) (934) Amortization charge — — (17) (17) Exchange differences — — 2 2 June 30, 2020 (853) — (96) (949) Net book amount as of June 30, 2020 8,743 — 81 8,824

Interest in joint venture

Interest in joint venture	6 Months Ended
	Jun. 30, 2021
Interests In Other Entities [Abstract]
Interest in joint venture	Interest in joint venture On December 14, 2020, the Company announced the formation of a new joint venture company, Overland ADCT BioPharma, with Overland Pharmaceuticals (“Overland”), a fully integrated biopharmaceutical company backed by Hillhouse Capital. Overland ADCT BioPharma will develop and commercialize one of the Company’s ADC products, ZYNLONTA, and three of the Company’s ADC product candidates, ADCT-601, ADCT-602 and ADCT-901 (collectively, the “Licensed Products”), in greater China and Singapore (the “Territory”). The table below provides a rollforward of the Company’s interest in Overland ADCT BioPharma as of June 30, 2021. (in KUSD) Interest in joint venture January 1, 2021 47,908 Share of results in joint venture (1,696) June 30, 2021 46,212 As of June 30, 2021, the deferred gain arising from the Company’s contribution for its equity investment in the joint venture remained unchanged from December 31, 2020. The Company’s carrying value of its investment in a joint venture increases or decreases in relation to the Company’s proportionate share of comprehensive income or loss of the joint venture. When the Company’s share of losses of a joint venture exceeds the Company’s interest in that joint venture less the carrying value of the deferred gain described below, the Company ceases to recognize its share of further losses. Additional losses are recognized only to the extent that the Company has incurred legal or constructive obligations or made payments on behalf of the joint venture. The tables below provide summarized financial information for Overland ADCT BioPharma that are material to the Company. The following information reflects the amounts presented in the financial statements of Overland ADCT BioPharma and not the Company’s share of those amounts. (in KUSD) As of Summarized Balance Sheet June 30, 2021 December 31, 2020 Cash and cash equivalents 46,636 50,000 Prepaid and other current assets 111 — Intangible assets 48,040 48,040 Total liabilities 590 269 Net assets 94,197 97,771 Summarized Statement of Comprehensive Loss (1) Three Months Ended June 30, 2021 Six Months Ended June 30, 2021 Operating expenses 2,493 3,655 Net loss 2,387 3,461

Leases

Leases	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Leases	LeasesDuring the first quarter of 2021, the Company entered into a new lease agreement with a ten-year term commencing in January 2021 for space in the iHub building on the Imperial University college campus in White City, West London. The primary function of the new facility, which consists of approximately 1,100 square meters, will be R&D. Pursuant to the terms of the agreement, the aggregate minimum lease payments for the first five years are fixed at which point the parties agree to perform an open market review, subject to a minimum and maximum rent escalation of 2% and 4%, respectively. Alternatively, the Company has the contractual right to exit the lease upon the fifth anniversary of lease commencement. In accounting for its Right-of-use asset and Lease liability, the Company concluded it was reasonably certain that it would occupy the space for the full ten-year term. During the second quarter of 2021, the Company entered into a new 18-month lease for its existing U.S. corporate offices in New Jersey, which commenced in June 2021. (in KUSD) Right-of-Use Assets Properties (Offices) Vehicles Total Cost January 1, 2021 5,324 78 5,402 Additions 5,662 56 5,718 Lease termination (864) — (864) Exchange difference 40 — 40 June 30, 2021 10,162 134 10,296 Accumulated depreciation January 1, 2021 (2,253) (20) (2,273) Depreciation charge (786) (13) (799) Lease termination 864 — 864 Exchange difference (11) — (11) June 30, 2021 (2,186) (33) (2,219) Net book amount as of June 30, 2021 7,976 101 8,077 Cost January 1, 2020 5,887 78 5,965 Exchange difference (103) — (103) June 30, 2020 5,784 78 5,862 Accumulated depreciation January 1, 2020 (1,067) — (1,067) Depreciation charge (559) (10) (569) Exchange difference 22 — 22 June 30, 2020 (1,604) (10) (1,614) Net book amount as of June 30, 2020 4,180 68 4,248 Depreciation of right-of-use assets have been charged to the following categories in the unaudited condensed consolidated interim statement of operations. Depreciation expense for S&M expenses was not material for any of the periods presented. Three months ended June 30, Six months ended June 30, (in KUSD) 2021 2020 2021 2020 R&D expenses 358 226 682 453 G&A expenses 62 57 117 116 420 283 799 569 (in KUSD) Lease liabilities Properties (Offices) Vehicles Total January 1, 2021 3,402 65 3,467 Additions 5,662 56 5,718 Cash outflow (including interest) (616) (15) (631) Interest 112 2 114 Exchange difference (66) (2) (68) June 30, 2021 8,494 106 8,600 January 1, 2020 4,953 78 5,031 Cash outflow (including interest) (605) (10) (615) Interest 60 1 61 Exchange difference (45) 1 (44) June 30, 2020 4,363 70 4,433 June 30, 2021 Lease liabilities (short-term) 954 34 988 Lease liabilities (long-term) 7,540 72 7,612 Total lease liabilities 8,494 106 8,600 June 30, 2020 Lease liabilities (short-term) 1,080 19 1,099 Lease liabilities (long-term) 3,283 51 3,334 Total lease liabilities 4,363 70 4,433

Convertible loans

Convertible loans	6 Months Ended
	Jun. 30, 2021
Financial Instruments [Abstract]
Convertible loans	Convertible loans Facility agreement On April 24, 2020, the Company entered into a USD 115 million Facility Agreement with Deerfield Partners, L.P. and certain of its affiliates (“Deerfield”). Pursuant to such agreement, Deerfield agreed to extend senior secured convertible term loans to the Company in two separate disbursements: (i) an initial disbursement of convertible loans in the amount of USD 65 million upon the completion of the initial public offering (“IPO”), and satisfaction of certain other conditions (the “first tranche”) and (ii) a subsequent disbursement of convertible loans in the amount of USD 50 million upon the receipt of regulatory approval for ZYNLONTA, and satisfaction of certain other conditions (the “second tranche”). The outstanding principal amount of the convertible loans is due to be repaid in full on May 19, 2025. However, any conversion of the convertible loans into common shares shall be deemed a repayment of the principal amount of the convertible loans so converted. The convertible loans bear interest at a rate of 5.95% per annum, based on a 360-day year, with interest payable quarterly in arrears commencing July 1, 2020 and July 1, 2021 for the first tranche and second tranche, respectively. Upon any payment of the convertible loans or conversion of the convertible notes, whether upon redemption or at maturity or at any other time, the Company will be required to pay an exit charge equal to 2.0% of the amount of the loans so paid or converted. The Company’s obligations under the Facility Agreement are guaranteed by the Company’s wholly owned subsidiaries and secured by a perfected, first-priority security interest in substantially all of the Company’s and its wholly owned subsidiaries’ personal property, including its intellectual property and the equity ownership interests directly and indirectly held by the Company in its wholly owned subsidiaries and joint venture. In accordance with the terms of the convertible notes, both the holders and the Company may elect to redeem the notes upon the occurrence of a major transaction and successor major transaction, respectively, as discussed in the Company’s annual report for the period ended December 31, 2020 on Form 20-F. The Facility Agreement contains various covenants, including a requirement to retain USD 50 million in cash and cash equivalents as of the end of each fiscal quarter. First tranche - Initial disbursement of convertible loans The Company has accounted for the first tranche of convertible loans amounting to USD 65 million issued on May 19, 2020 as comprising two components: an embedded conversion option derivative and a loan. Valuation of derivative embedded in first tranche Since issuance, the embedded conversion option derivative is marked-to-market on a quarterly basis. During the three and six months ended June 30, 2021, the Company recognized income of KUSD 5,512 and KUSD 20,780 as a result of changes in the fair value of the embedded derivative. During both the three and six months ended June 30, 2020, the Company recognized expense of KUSD 57,450 as a result of changes in the fair value of the embedded derivative. The fair value of the embedded derivative associated with the first tranche was KUSD 30,449 and KUSD 51,229 as of June 30, 2021 and December 31, 2020, respectively. The decrease in fair value of the embedded derivative during the three and six months ended June 30, 2021 is primarily due to the decrease in the fair value of the underlying shares from December 31, 2020 to June 30, 2021, which was charged directly to the unaudited condensed consolidated interim statement of operations. The increase in fair value of the embedded derivative during both the three and six months ended June 30, 2020 was primarily due to the increase in the fair value of the underlying shares from April 24, 2020 to June 30, 2020. The Company used an independent valuation firm to assist in calculating the fair value of the embedded conversion option derivative, which is based on the mean of values derived from application of the Hull and Goldman Sachs convertible bond pricing models. Key inputs for the valuations as of June 30, 2021 and December 31, 2020 were as follows: As of June 30, 2021 December 31, 2020 Exercise price at 130% of the IPO price of 19.00, in USD 24.70 24.70 Forced conversion price, in USD (1) 67.93 67.93 Share price in USD 24.35 32.01 Risk-free interest rate 0.6 % 0.3 % Expected volatility (2) 70 % 90 % Expected term 46 months 52 months Dividend yield — — Recovery rate 5 % 5 % Implied bond yield 8.0 % 13.3 % (1) In accordance with the terms of the convertible loans, under certain circumstances the Company has the right to force conversions of the convertible notes on and after the one- and three-year anniversaries of the date on which it has received regulatory approval of ZYNLONTA as discussed in the Company’s annual report for the period ended December 31, 2020 on Form 20-F. (2) The expected volatility utilized for the June 30, 2021 valuation decreased from that used in the December 31, 2020 valuation due to a change in the peer group. Prior to the FDA approval of ZYNLONTA, the Company utilized a peer group primarily comprised of clinical-stage companies. Upon receipt of FDA approval of ZYNLONTA, the Company updated the peer group to primarily comprise of commercial-stage companies, which lowered the expected volatility assumption utilized in the June 30, 2021 valuation. Residual convertible loan The loan bears interest at a rate of 5.95% per annum, based on a 360-day year, with interest payable quarterly in arrears commencing on July 1, 2020. For the three and six months ended June 30, 2021, the Company recorded interest expense related to the interest payable on the residual convertible loan (net of the value of the embedded conversion option derivative) in the amount of KUSD 2,060 and KUSD 4,042, respectively. For both the three and six ended June 30, 2020, the Company recorded interest expense related to the interest payable on the residual convertible loan (net of the value of the embedded conversion option derivative) in the amount of KUSD 868. The Company’s interest expense is based on the implied effective interest rate, which was computed at inception at 23%. The convertible loan’s initial fair value was determined as the residual amount of the consideration received, net of attributable costs, after separating out the fair value of the embedded conversion option derivative. Transaction costs associated with the convertible loan were allocated to the embedded conversion option derivative and residual loan as follows: in KUSD Embedded derivative Residual loan Total Gross proceeds 27,797 37,203 65,000 Less: transaction costs (1,571) (2,102) (3,673) Net 26,226 35,101 61,327 The transaction costs of the embedded derivative were charged directly to the unaudited condensed consolidated interim statement of operations. The convertible loan is subsequently measured at its amortized cost in accordance with IFRS 9. The amount at which the convertible loan is presented as a liability in the unaudited condensed consolidated interim balance sheet represents the net present value of all future cash outflows associated with the loan discounted at the implied effective interest rate. The net present value of those cash outflows occurring within 12 months of the balance sheet date discounted at the same rate is presented as a short-term liability. The remainder of the amount is presented as a long-term liability. The carrying value of the convertible loan was KUSD 40,493 as of June 30, 2021, of which KUSD 3,629 was the current portion of the liability. The carrying value of the convertible loan was KUSD 38,406 as of December 31, 2020, of which KUSD 3,631 was the current portion of the liability. Second tranche - Accounting for subsequent disbursement of convertible loans prior to FDA approval Draw-down of the second tranche of the convertible loans was mandatory upon receipt of regulatory approval for ZYNLONTA. Prior to drawing down the second tranche, the Company accounted for the second tranche as a derivative. The Company performed a valuation of the derivative immediately prior to the April 23, 2021 approval of ZYNLONTA, which resulted in a mark-to-market adjustment and recognition of KUSD 4,263 of expense and KUSD 1,638 of income for the three and six months ended June 30, 2021, respectively. The increase in fair value of the derivative from April 1, 2021 through immediately prior to the April 23, 2021 FDA approval was primarily due to the increase in the fair value of the underlying shares as well as utilizing a 100% probability of achieving regulatory approval for ZYNLONTA, which was charged directly to the unaudited condensed consolidated statement of operations. The decrease in fair value of the derivative during six months ended June 30, 2021 is primarily due to the decrease in the fair value of the underlying shares from December 31, 2020 to immediately prior to the April 23, 2021 FDA approval, which was charged directly to the unaudited condensed consolidated statement of operations. The fair value of the derivative associated with the second tranche as of June 30, 2021 was nil as the derivative is now accounted for as an embedded conversion option derivative upon the draw-down of the subsequent disbursement. See “Second tranche - Accounting for subsequent disbursement of convertible loans after FDA approval” below for further details. During both the three and six months ended June 30, 2020, the Company recognized expense of KUSD 21,811 as a result of changes in the fair value of the derivative. The increase in fair value of the derivative was primarily due to the increase in the fair value of the Company’s shares from April 24, 2020 to June 30, 2020 and has been charged directly to the unaudited condensed consolidated interim statement of income. The fair value of the of the derivative associated with the second tranche was KUSD 21,979 as of December 31, 2020. The Company used an independent valuation firm to assist in performing a fair value assessment of the derivative liability, which is based on the mean of values derived from application of the Hull and Goldman Sachs convertible bond pricing models. Key inputs for the valuation as of April 23, 2021 (prior to FDA approval of ZYNLONTA) and December 31, 2020 were as follows: As of April 23, 2021 December 31, 2020 Exercise price at 150% of the IPO of 19.00, in USD (1) 28.50 28.50 Forced conversion price, in USD (2) 78.38 78.38 Share price in USD (3) 24.85 32.01 Risk-free interest rate 0.6 % 0.3 % Expected volatility 90 % 90 % Expected term 1 month 5 months Dividend yield — — Recovery rate 5 % 5 % Implied bond yield 7.7 % 7.4 % (1) The conversion price for the second tranche of convertible notes is the lesser of (i) 150% of the IPO price and (ii) 120% of the average of the volume-weighted average prices of the Company’s common shares on each of the 15 trading days immediately prior to the disbursement date of the second tranche, but in no event less than a floor equal to 81% of the IPO price. (2) In accordance with the terms of the convertible loans, under certain circumstances the Company has the right to force conversions of the convertible notes on and after the one- and three-year anniversaries of the date on which it received regulatory approval of ZYNLONTA, as discussed in the Company’s annual report for the period ended December 31, 2020 on Form 20-F. (3) The Company utilized the opening share price on April 23, 2021 for the valuation of the derivative immediately prior to FDA approval of ZYNLONTA. Second tranche - Accounting for subsequent disbursement of convertible loans after FDA approval Upon receipt of FDA approval of ZYNLONTA, the Company accounted for the second tranche of convertible loans amounting to USD 50 million issued on May 17, 2021 as comprising two separate components: an embedded conversion option derivative and a loan. Valuation of derivative embedded in second tranche The Company used an independent valuation firm to assist in calculating the initial fair value of the entire instrument, including the embedded conversion option derivative, as of April 23, 2021. The fair value of the embedded conversion option derivative component was based on the mean of values derived from application of the Hull and Goldman Sachs convertible bond pricing models. Key inputs for the subsequent valuation of the embedded conversion option derivative as of June 30, 2021 and the initial valuation of the entire instrument, including both components described above, after FDA approval of ZYNLONTA was obtained on April 23, 2021 were as follows: As of June 30, 2021 April 23, 2021 Exercise price in USD (1) 28.07 28.50 Forced conversion price, in USD (2) 77.19 78.38 Share price in USD (3) 24.35 23.25 Risk-free interest rate 0.6 % 0.6 % Expected volatility 70 % 75 % Expected term 46 months 48 months Dividend yield — — Recovery rate 5 % 5 % Implied bond yield 8.0 % 6.3 % (1) The conversion price for the second tranche of convertible notes is the lesser of (i) 150% of the IPO price and (ii) 120% of the average of the volume-weighted average prices of the Company’s common shares on each of the 15 trading days immediately prior to the disbursement date of the second tranche, but in no event less than a floor equal to 81% of the IPO price. The conversion price for the second tranche of the convertible notes as of June 30, 2021 was based on 120% of the average of the volume-weighted average process of the Company’s shares on each of the 15 trading days prior to the disbursement date, while the conversion price as of April 23, 2021 was based on 150% of the IPO price. (2) In accordance with the terms of the convertible loans, under certain circumstances the Company has the right to force conversions of the convertible notes on and after the one- and three-year anniversaries of the date on which it received regulatory approval of ZYNLONTA, as discussed in the Company’s annual report for the period ended December 31, 2020 on Form 20-F. (3) The Company utilized the closing share price on April 23, 2021 for the valuation of the embedded conversion option derivative after FDA approval of ZYNLONTA. The expected volatility utilized for the post-FDA approval valuations decreased from those used in the pre-FDA approval valuations due to a change in the peer group. Prior to the FDA approval of ZYNLONTA, the Company utilized a peer group primarily comprised of clinical-stage companies. Upon receipt of FDA approval of ZYNLONTA, the Company updated the peer group to primarily comprise of commercial-stage companies, which lowered the expected volatility assumption utilized in the post-FDA approval valuations. The following table presents the initial fair value of the entire instrument as of April 23, 2021, including both components, relating to the USD 50.0 million subsequent disbursement. The Company received net cash proceeds of USD 49.4 million after deducting aggregate transaction costs associated with the subsequent disbursement. Transaction costs associated with the subsequent disbursement were allocated to the embedded conversion option derivative and convertible loan as follows: in KUSD Embedded derivative Convertible loan Total Fair value as of April 23, 2021 18,158 50,368 68,526 Allocation of transaction costs (148) (409) (557) Net carrying value of convertible loan as of April 23, 2021 49,959 The transaction costs of the embedded derivative were charged directly to the unaudited condensed consolidated interim statement of operations. During the three and six months ended June 30, 2021, the Company recognized expense of KUSD 1,012 as a result of changes in the fair value of the embedded derivative after the April 23, 2021 approval date. The fair value of the embedded derivative associated with the second tranche was KUSD 19,170 and KUSD 18,158 as of June 30, 2021 and after the April 23, 2021 approval date, respectively. The increase in fair value of the embedded derivative is primarily due to the increase in the fair value of the underlying shares from April 23, 2021 to June 30, 2021. Convertible loan The loan bears interest at a rate of 5.95% per annum, based on a 360-day year, with interest payable quarterly in arrears commencing on July 1, 2021. For both the three and six months ended June 30, 2021, the Company recorded interest expense related to the interest payable on the convertible loan (net of the value of the embedded conversion option derivative) in the amount of KUSD 390 based on the implied effective interest rate, which was computed at inception at 6.7%. As described above, the Company used an independent valuation firm to assist in calculating the initial fair value of the entire instrument, including both components. The Company recorded the initial carrying amount of the convertible loan based on its fair value as of April 23, 2021. Refer to the tabular disclosure above for the key inputs used for the initial valuation after FDA approval of ZYNLONTA was obtained on April 23, 2021. The convertible loan will be subsequently measured at its amortized cost in accordance with IFRS 9. The amount at which the convertible loan is presented as a liability in the unaudited condensed consolidated interim balance sheet represents the net present value of all future cash outflows associated with the loan discounted at the implied effective interest rate. The net present value of those cash outflows occurring within 12 months of the balance sheet date discounted at the same rate is presented as a short-term liability. The remainder of the amount is presented as a long-term liability. The carrying value of the convertible loan was KUSD 50,348 as of June 30, 2021, of which KUSD 2,564 was the current portion of the liability. Other In connection with the receipt of the USD 50.0 million subsequent disbursement, the establishment of the embedded derivative and residual loan associated with the subsequent disbursement and elimination of the aforementioned derivative immediately prior to FDA approval of ZYNLONTA, the Company recorded a gain of KUSD 1,816 during the three and six months ended June 30, 2021, which was recorded in Convertible loans, derivatives, change in fair value income (expense) in the unaudited condensed consolidated interim statement of operations.
Schedule of Derivative Option and Convertible Loan	The following table presents the initial fair value of the entire instrument as of April 23, 2021, including both components, relating to the USD 50.0 million subsequent disbursement. The Company received net cash proceeds of USD 49.4 million after deducting aggregate transaction costs associated with the subsequent disbursement. Transaction costs associated with the subsequent disbursement were allocated to the embedded conversion option derivative and convertible loan as follows: in KUSD Embedded derivative Convertible loan Total Fair value as of April 23, 2021 18,158 50,368 68,526 Allocation of transaction costs (148) (409) (557) Net carrying value of convertible loan as of April 23, 2021 49,959

Share-based compensation

Share-based compensation	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangements [Abstract]
Share-based compensation	Share-based compensation Share Purchase Plan 2013 and Share Purchase Plan 2016 The Share Purchase Plan 2013 and Share Purchase Plan 2016 were both terminated on May 15, 2020. All compensation expense relating to the Share Purchase Plan 2013 was recognized in prior periods. The amount of expense under the Share Purchase Plan 2016 for all awards recognized for services received during the three and six months ended June 30, 2020 was KUSD 6,425 and KUSD 7,417, respectively. There was no expense recognized under the Share Purchase Plan 2016 for fiscal 2021. Incentive Plan 2014 All existing awards under the Incentive Plan 2014 vested and were settled in shares upon the completion of the May 19, 2020 IPO. For participants whose awards had an exercise price greater than USD 19.00 — i.e., were “out-of-the-money” — the Company made an equal number of new awards under the Equity Incentive Plan 2019 (see below) with an exercise price of USD 19.00 and with a vesting period of only three years instead of the usual four years. A total of 356,144 shares were transferred to participants and an amount of KUSD 5,343 was withheld for tax and social charges. These new awards have been accounted for as a modification of the previous awards under the Incentive Plan 2014. Accordingly, the original compensation expense calculated for the old awards that were “out-of-the-money” will continue to be recognized over their remaining vesting period while the expense to be recognized for the new awards under the Equity Incentive Plan 2019 will be limited to the incremental fair value of the new awards over the fair value, as of May 15, 2020, of the old awards. The amounts of expense for all awards recognized for services received during the three and six months ended June 30, 2020 was KUSD 179 and KUSD 361, respectively. Equity Incentive Plan 2019 In November 2019, the Company adopted the Equity Incentive Plan 2019. Under the Equity Incentive Plan 2019, the Company may at its discretion grant to plan participants, such as directors, certain employees and service providers, awards in the form of restricted shares and restricted share units (“RSUs”), share options, share appreciation rights, performance awards and other share-based awards. The Company has reserved 13,820,000 common shares for future issuance under the Equity Incentive Plan 2019 (including share-based equity awards granted to date less awards forfeited), which includes an additional 6,000,000 common shares approved by the Company’s board of directors on March 29, 2021. As of June 30, 2021, the Company has 6,996,626 common shares available for the future issuance of share-based equity awards. On March 22, 2021, the Company issued its first annual equity award, which was approved by the Compensation Committee of the Board of Directors and consisted of 1,592,651 share options and 377,255 RSUs. As of June 30, 2021, the Company has only granted share options and RSUs under the Equity Incentive Plan 2019. As of June 30, 2021, the cumulative amount recorded as an increase to Other Reserves within equity in the unaudited condensed consolidated interim balance sheet of the Equity Incentive Plan 2019 was KUSD 67,716. The amount of expense for all awards recognized for services received during the three and six months ended June 30, 2021 were KUSD 18,267 and KUSD 32,218, respectively, and for the three and six months ended June 30, 2020 were KUSD 6,130 and KUSD 8,746, respectively. Share Options Pursuant to the Equity Incentive Plan 2019, the Company may grant share options to its directors, certain employees and service providers working for the benefit of the Company at the time. The exercise price per share option is set by the Company at the fair market value of the underlying common shares on the date of grant, as determined by the Company, which is generally the closing share price of the Company’s common shares traded on the NYSE. The awards generally vest 25% on the first anniversary of the date of grant, and thereafter evenly on a monthly basis over the subsequent three years. The contractual term of each share option award granted is ten years. Under the grant, the options may be settled only in common shares of the Company. Therefore, the grants of share options under the Equity Incentive Plan 2019 have been accounted for as equity-settled under IFRS 2. As such, the Company records a charge for the vested portion of award grants and for partially earned but non-vested portions of award grants. This results in a front-loaded charge to the Company’s unaudited condensed consolidated interim statement of operations and a corresponding increase to Other Reserves within equity on the unaudited condensed consolidated interim balance sheet. The expense recognized for services received during the three and six months ended June 30, 2021 is KUSD 15,315 and KUSD 28,007, respectively. The expense recognized for services received during the three and six months ended June 30, 2020 is KUSD 6,130 and KUSD 8,746, respectively. The following table summarizes the share option awards outstanding as of June 30, 2021: Average strike price per share in USD Number of awards Weighted average remaining life December 31, 2020 26.45 4,276,973 9.29 Granted 28.66 2,077,385 9.69 Forfeited 25.22 (64,933) N/A Expired 18.75 (1,250) N/A Exercised 18.75 (12,519) N/A June 30, 2021 27.21 6,275,656 9.11 Awards outstanding as of June 30, 2021 and December 31, 2020, expire through 2031. The options granted during 2021 include the Company’s first annual equity award discussed above. The weighted-average grant-date fair value of the options relating to the annual equity awards was USD 20.53 per share. As of June 30, 2021, 1,175,927 awards are vested and exercisable out of the total outstanding awards of 6,275,656 common shares. The weighted average strike price and weighted average remaining life for vested and exercisable awards is USD 20.48 and 8.72 years, respectively. The fair values of the options granted were determined on the date of the grant using the Black-Scholes option-pricing model. The Company used an independent valuation firm to assist in calculating the fair value of the award grants per participant. The fair values of the options granted during the three and six months ended June 30, 2021 were determined on the date of the grant using the following assumptions: Three Months Ended Six Months Ended June 30, 2021 June 30, 2021 Share price, in USD 22.16 - 25.52 22.16 - 32.22 Strike price, in USD 22.16 - 25.52 22.16 - 32.22 Expected volatility 70% - 85% 70% - 85% Award life 6.08 5.5 - 6.08 Expected dividends — — Risk-free interest rate 1.06% - 1.15% 0.51% - 1.15% The expected volatility was based on the Company’s historical volatility and selected volatility determined by median values observed among other comparable public companies. The expected volatility utilized after FDA approval of ZYNLONTA decreased from those used prior to FDA approval due to a change in the peer group. Prior to FDA approval, the Company utilized a peer group primarily comprised of clinical-stage companies. Upon receipt of FDA approval, the Company updated the peer group to primarily comprise of commercial-stage companies, which lowered the expected volatility assumption. The award life is based on the time interval between the date of grant and the date during the ten-year life after which, when making the grant, the Company expected on average that participants would exercise their options. RSUs Pursuant to the Equity Incentive Plan 2019, the Company may grant RSUs to its directors, certain employees and service providers working for the benefit of the Company at the time. The awards generally vest annually over a period of three years commencing on the first anniversary of the date of grant. Under the grant, the RSUs may be settled only in common shares of the Company. Therefore, the grants of RSUs under the Equity Incentive Plan 2019 have been accounted for as equity-settled under IFRS 2. As such, the Company records a charge for the vested portion of award grants and for partially earned but non-vested portions of award grants. This results in a front-loaded charge to the Company’s unaudited condensed consolidated interim statement of operations and a corresponding increase to Other Reserves within equity on the unaudited condensed consolidated interim balance sheet. The expense recognized for services received during the three and six months ended June 30, 2021 was KUSD 2,952 and KUSD 4,211, respectively. Number of awards Weighted average grant date fair value December 31, 2020 149,984 46.50 Granted 412,099 28.70 Forfeited (1,846) N/A June 30, 2021 560,237 33.45 The RSUs granted during 2021 include the first annual equity award discussed above. There were no vested RSUs during the six months ended June 30, 2021. The Company did not issue any grants of RSUs prior to June 30, 2020. Share-based Compensation Reserves The movement in the Share-based Compensation Reserves (included in Other reserves within equity) is as follows: Three months ended Six months ended (in KUSD) June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Incentive Plan 2014 — 179 — 361 Share Purchase Plan 2016 — 6,425 — 7,417 Equity Incentive Plan 2019 - Share Options 15,315 6,130 28,007 8,746 Equity Incentive Plan 2019 - RSUs 2,952 — 4,211 — Tax and social charge deductions - Incentive Plan 2014 — (5,343) — (5,343) Total 18,267 7,391 32,218 11,181

Related parties

Related parties	6 Months Ended
	Jun. 30, 2021
Related Party [Abstract]
Related parties	Related parties Parties are considered to be related if one party has the ability, directly or indirectly, to control the other party or exercise significant influence over the other party in making financial and operating decisions. A.T. Holdings II Sàrl (“AT Holdings II”) is a shareholder in the Company. AT Holdings II is in turn ultimately wholly owned by Auven Therapeutics Holdings, L.P. (“ATH”), a limited partnership registered in the British Virgin Islands. ATH’s General Partner is Auven Therapeutics General L.P., which itself is a limited partnership whose General Partner is Auven Therapeutics GP Ltd. The manager of ATH is Auven Therapeutics Management L.L.L.P. (“ATM”). Based on the Company’s contribution and equity interest in Overland ADCT BioPharma, certain of the Company’s employees serve on its board of directors. Services provided by the Company to related parties The Company provides registered office and other simple administrative services to three subsidiaries of ATH. The amounts invoiced for the three and six months ended June 30, 2021 and recovered through G&A expenses, amounted to KUSD 1 and KUSD 2, respectively (three and six months ended June 30, 2020: KUSD 2). As contemplated by the license agreement with Overland ADCT BioPharma, Overland ADCT BioPharma has elected to participate in certain of the Company’s global clinical trials, in exchange for which it reimburses the Company for a portion of the cost of those trials. Overland ADCT BioPharma also reimburses the Company for certain expenses in connection with technology transfer and assistance of clinical personnel. During the three and six months ended June 30, 2021, the Company incurred KUSD 790 of clinical trial and service costs to be reimbursed by Overland ADCT BioPharma, which is recorded as a reduction of R&D expenses in the Company’s unaudited condensed consolidated interim statement of operations. Key management compensation The compensation of key management is shown below: Three months ended June 30, Six months ended June 30, (in KUSD) 2021 2020 2021 2020 Salaries and other short-term employee costs 1,969 1,666 4,001 3,254 Pension costs 106 107 240 256 Share-based compensation expense 8,604 6,025 13,821 7,599 Other compensation 9 22 22 83 Total 10,688 7,820 18,084 11,192

Loss per share

Loss per share	6 Months Ended
	Jun. 30, 2021
Earnings per share [abstract]
Loss per share	Loss per share Three Months Ended June 30, Six Months Ended June 30, (in KUSD, except per share amounts) 2021 2020 2021 2020 Loss attributable to owners (72,569) (126,557) (124,096) (170,033) Weighted average number of shares outstanding 76,728,714 62,863,866 76,725,210 57,225,939 Basic and diluted loss per share (0.95) (2.01) (1.62) (2.97) For the three and six months ended June 30, 2021 and 2020, basic and diluted loss per share are calculated on the weighted average number of shares issued and outstanding and exclude shares to be issued under the Equity Incentive Plan 2019, as the effect of including those shares would be anti-dilutive. Potentially dilutive securities that were not included in the diluted per share calculations because the effect of including them would be anti-dilutive were as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Equity Incentive Plan 2019 - Share Options 6,258,291 2,784,467 5,475,476 1,999,022 Equity Incentive Plan 2019 - RSUs 560,967 — 379,379 — Conversion of the principal amount of convertible loans into the Company’s common shares 3,982,206 1,766,917 3,310,623 888,340 10,801,464 4,551,384 9,165,478 2,887,362

Events after the reporting date

Events after the reporting date	6 Months Ended
	Jun. 30, 2021
Events After Reporting Period [Abstract]
Events after the reporting date	Events after the reporting dateThe Company has evaluated its subsequent events through August 3, 2021, the date the unaudited condensed consolidated interim financial statements were available to be issued, and has concluded that there are no subsequent events requiring disclosure in these unaudited condensed consolidated interim financial statements.

Significant accounting polici_2

Significant accounting policies (Policies)	6 Months Ended
	Jun. 30, 2021
Accounting Policies, Changes in Accounting Estimates And Errors [Abstract]
Statement of Compliance	Statement of Compliance These unaudited condensed consolidated interim financial statements as of and for the three and six months ended June 30, 2021 have been prepared in accordance with International Accounting Standard 34 Interim Financial Reporting (“IAS 34”) and should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2020.
Revenue Recognition	Revenue Recognition Upon the April 23, 2021 FDA approval of ZYNLONTA for the treatment of relapsed or refractory DLBCL, the Company began generating revenue from the sale of its product candidates. In previous years, the Company had generated only service revenues from a license and collaboration arrangement. Revenue from the sale of products is recognized in a manner that depicts the transfer of those promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for these goods or services. To achieve this core principle, the Company follows a five-step model: (i) identify the customer contract; (ii) identify the contract’s performance obligation; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations; and (v) recognize revenue when, or as, a performance obligation is satisfied. Revenue is also reduced for GTN sales adjustments, which may include government rebates, chargebacks, distributor service fees, other rebates and administrative fees, sales returns and allowances and sales discounts. GTN sales adjustments involve significant estimates and judgment after considering factors including legal interpretations of applicable laws and regulations, historical experience and drug product analogs in the absence of Company experience, payer channel mix, current contract prices under applicable programs, unbilled claims and processing time lags and inventory levels in the distribution channel. The Company also uses information from external sources to identify prescription trends, patient demand, average selling prices and sales return and allowance data for analog drug products. The Company’s estimates are subject to inherent limitations of estimates that rely on third-party information, as certain third-party information was itself in the form of estimates, and reflect other limitations including lags between the date as of which third-party information is generated and the date on which the Company receives third-party information. Estimates will be assessed each period and adjusted as required to revise information or actual experience. Cost of product sales Cost of product sales primarily includes direct and indirect costs relating to the manufacture of ZYNLONTA from third-party providers of manufacturing, distribution and logistics, intangible asset amortization expense, and royalties to a collaboration partner based on net product sales of ZYNLONTA. Inventory amounts written down as a result of excess or obsolescence are charged to Cost of product sales. Accounts Receivable Accounts receivable arise from product sales and consists of amounts due from customers, net of customer allowances for chargebacks, product returns and estimated credit losses. Upon the launch of ZYNLONTA, the Company’s contracts with customers have initial payment terms that range from 30 to 150 days. When determining customer allowances for estimated credit losses, the Company analyzes accounts that are past due, the creditworthiness of its customers, current economic conditions and, when sufficient historical data becomes available, actual credit losses incurred by the Company. As of June 30, 2021, the Company determined an allowance for expected credit losses was not required based upon the assessment performed. Inventory Prior to receiving FDA approval of ZYNLONTA, the Company had written down inventory costs relating to the manufacture of ZYNLONTA to a net realizable value of zero. The Company believed that capitalization of inventory costs associated with certain products prior to regulatory approval of such products, or for inventory produced in new production facilities, was only appropriate when management considered it highly probable that pre-approval inventory costs would be recoverable through future sales of the drug product. The determination to capitalize was based on the particular facts and circumstances related to the expected regulatory approval of the product or production facility being considered and, accordingly, the time frame within which the determination was made varied from product to product. The impairment charges were recorded as Research and development (“R&D”) expenses in the Company’s condensed consolidated interim statement of operations. Upon the receipt of FDA approval for ZYNLONTA, the Company reversed KUSD 6,752 of previously recorded impairment charges based on a number of factors existing at that time, including the existence of inventory on hand and estimated demand, as well as expiration dating. The reversal of impairment charges was recorded as a gain to R&D expenses in the Company’s unaudited condensed consolidated interim statement of operations. The amount of the impairment reversal may increase in future periods based on future enhancements that may extend the shelf life of the components used to manufacture ZYNLONTA and/or of the ultimate drug product. Inventory of ZYNLONTA is stated at the lower of cost or net realizable value with costs determined on a first-in, first-out basis. The Company assesses the recoverability of capitalized inventory during each reporting period and will write down excess or obsolete inventory to its net realizable value in the period in which the impairment is identified within Cost of product sales in the unaudited condensed consolidated interim statement of operations. The Company has not recorded any material inventory impairments since the FDA approved ZYNLONTA. Included in inventory are materials used in the production of preclinical and clinical products, which are charged to R&D expenses when consumed. The Company will continue to assess the likelihood that inventory costs associated with its other drug product candidates are recoverable through future sales of such product candidates to determine if and when such costs should be capitalized as inventory or be expensed to R&D expenses. The assessment of whether or not the product is considered highly probable to be saleable will be made on a quarterly basis and includes, but is not limited to, how far a particular product or facility has progressed along the approval process, any known safety or efficacy concerns, potential labeling restrictions and other impediments. If it is determined that inventory costs associated with a product candidate are not highly probable to be recovered through future sales, the Company would record such costs to R&D expenses. Intangible assets Licenses Licenses acquired are capitalized as intangible assets at historical cost. Licenses with definite useful lives are amortized over their useful lives, which are determined on a basis of the expected pattern of consumption of the expected future economic benefits embodied in the licenses and which therefore commence only once the necessary regulatory and marketing approvals have been received. Prior to regulatory and marketing approval, licenses are treated as indefinite-lived assets and not amortized. These licenses are tested annually for impairment in the last quarter of each fiscal year and more frequently if events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. Amortization and impairment of licenses Prior to regulatory and marketing approval, impairment of indefinite-lived licenses is charged to R&D expenses. Subsequent to regulatory and marketing approval, amortization of licenses will be charged to Cost of product sales over the licenses’ estimated useful lives. The useful life of definite-lived intangible assets will depend upon the legal term of the individual patent in the country in which the patent is obtained. In determining the useful life, the Company utilizes the last-to-expire period of exclusivity (primary patent or regulatory approval) related to the primary marketed drug product. The Company may be able to obtain a patent term extension. However, the Company will only consider the inclusion of an extension period to the extent the Company believes it is highly probable of being granted. See note 10, “Intangible assets” for further information.
New and amended IFRS standards	New and amended IFRS standards There are no new IFRS standards, amendments to standards or interpretations that are mandatory for the financial year beginning on January 1, 2021, that are relevant to the Group and that have had any impact in the interim period. New standards, amendments to standards and interpretations that are not yet effective, which have been deemed by the Group as currently not relevant, are not listed here.
Income tax expense	Income tax expense Taxes on income in the interim periods are accrued using the tax rate that would be applicable to expected total annual profit or loss.
Functional and reporting currency	Functional and reporting currency These unaudited condensed consolidated interim financial statements are presented in United States Dollars (“USD” or “$”), which is the Company’s functional currency and the Group’s reporting currency.
Selling and marketing ("S&M") expenses	Selling and marketing ( “ S&M ” ) expenses

Basis of preparation (Tables)

Basis of preparation (Tables)	6 Months Ended
	Jun. 30, 2021
Corporate Information And Statement Of IFRS Compliance [Abstract]
Schedule of Foreign currency exchange rate	A subsidiary of the Company, ADCT UK, has a functional currency of the British Pound (“GBP”). The following exchange rates have been used for the translation of the financial statements of ADCT UK: Six Months Ended June 30, 2021 2020 USD / GBP Closing rate, GBP 1 1.38358 1.23272 Weighted average exchange rate, GBP 1 1.39134 1.23277 Basis of Consolidation
Schedule of consolidated entities	The consolidated entities include: Ownership Interest June 30, 2021 June 30, 2020 ADCT America 100 % 100 % ADCT UK 100 % 100 %

Product revenues, net (Tables)

Product revenues, net (Tables)	6 Months Ended
	Jun. 30, 2021
Revenue From Contracts With Customers [Abstract]
Disclosure Of Detailed Information About Sales Adjustments Explanatory	The table below provides a rollforward of the Company’s GTN sales adjustments for the six months ended June 30, 2021. (in KUSD) Total Beginning balance at January 1, 2021 — GTN sales adjustments related to sales in the current period 752 Credits and payments made (22) Ending balance as of June 30, 2021 730
Disclosure Of Detailed Information About Sales Adjustment Included In the Balance Sheets	The table below provides the classification of the GTN sales adjustment included in the Company’s unaudited condensed consolidated interim balance sheet as of June 30, 2021. (in KUSD) As of June 30, 2021 Accounts receivable, net 533 Other current liabilities 197

Expenses by nature (Tables)

Expenses by nature (Tables)	6 Months Ended
	Jun. 30, 2021
Analysis of income and expense [abstract]
Disclosure Of Detailed Information About Expenses By Nature Explanatory	The following table summarizes R&D expenses, S&M expenses and G&A expenses for the three and six months ended June 30, 2021 and 2020: (in KUSD) Three months ended June 30, Six months ended June 30, R&D 2021 2020 2021 2020 External costs (1) 21,983 16,161 46,289 42,300 Employee expense (2) 17,550 9,789 32,416 19,025 R&D expenses 39,533 25,950 78,705 61,325 S&M External costs 5,726 2,105 11,016 3,845 Employee expense (2) 9,495 1,899 18,116 2,787 S&M expenses 15,221 4,004 29,132 6,632 G&A External costs (1) 5,872 2,316 10,605 4,556 Employee expense (2) 13,495 12,679 26,344 16,321 G&A expenses 19,367 14,995 36,949 20,877 (1) Includes depreciation expense (2) Includes share-based compensation expense

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 30, 2021
Inventory [Abstract]
Disclosure Of Inventory Information Explanatory	Inventory as of June 30, 2021 consisted of the following: (in KUSD) As of June 30, 2021 Raw materials — Work in process 7,411 Finished goods (1) 307 Total inventory 7,718

Intangible assets (Tables)

Intangible assets (Tables)	6 Months Ended
	Jun. 30, 2021
Intangible Assets [Abstract]
Disclosure of reconciliation of changes in intangible assets and goodwill [text block]	The table below provides a rollforward of the Company’s intangible assets as of June 30, 2021 and 2020. (in KUSD) Cost Licenses - indefinite lived Licenses - definite lived Software Total January 1, 2021 11,144 — 168 11,312 Additions 1,300 600 — 1,900 Transfers (452) 452 (6) (6) June 30, 2021 11,992 1,052 162 13,206 Accumulated Amortization January 1, 2021 (1,069) — (64) (1,133) Amortization charge — (13) (50) (63) June 30, 2021 (1,069) (13) (114) (1,196) Net book amount as of June 30, 2021 10,923 1,039 48 12,010 Cost January 1, 2020 9,221 — 147 9,368 Additions 375 — 33 408 Exchange differences — — (3) (3) June 30, 2020 9,596 — 177 9,773 Accumulated Amortization January 1, 2020 (853) — (81) (934) Amortization charge — — (17) (17) Exchange differences — — 2 2 June 30, 2020 (853) — (96) (949) Net book amount as of June 30, 2020 8,743 — 81 8,824

Interest in joint venture (Tabl

Interest in joint venture (Tables)	6 Months Ended
	Jun. 30, 2021
Interests In Other Entities [Abstract]
Schedule of movement in interest in joint venture	The table below provides a rollforward of the Company’s interest in Overland ADCT BioPharma as of June 30, 2021. (in KUSD) Interest in joint venture January 1, 2021 47,908 Share of results in joint venture (1,696) June 30, 2021 46,212
Summary of financial information in join venture	The tables below provide summarized financial information for Overland ADCT BioPharma that are material to the Company. The following information reflects the amounts presented in the financial statements of Overland ADCT BioPharma and not the Company’s share of those amounts. (in KUSD) As of Summarized Balance Sheet June 30, 2021 December 31, 2020 Cash and cash equivalents 46,636 50,000 Prepaid and other current assets 111 — Intangible assets 48,040 48,040 Total liabilities 590 269 Net assets 94,197 97,771 Summarized Statement of Comprehensive Loss (1) Three Months Ended June 30, 2021 Six Months Ended June 30, 2021 Operating expenses 2,493 3,655 Net loss 2,387 3,461

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Schedule of quantitative information about right-of-use assets	(in KUSD) Right-of-Use Assets Properties (Offices) Vehicles Total Cost January 1, 2021 5,324 78 5,402 Additions 5,662 56 5,718 Lease termination (864) — (864) Exchange difference 40 — 40 June 30, 2021 10,162 134 10,296 Accumulated depreciation January 1, 2021 (2,253) (20) (2,273) Depreciation charge (786) (13) (799) Lease termination 864 — 864 Exchange difference (11) — (11) June 30, 2021 (2,186) (33) (2,219) Net book amount as of June 30, 2021 7,976 101 8,077 Cost January 1, 2020 5,887 78 5,965 Exchange difference (103) — (103) June 30, 2020 5,784 78 5,862 Accumulated depreciation January 1, 2020 (1,067) — (1,067) Depreciation charge (559) (10) (569) Exchange difference 22 — 22 June 30, 2020 (1,604) (10) (1,614) Net book amount as of June 30, 2020 4,180 68 4,248
Schedule of quantitative information about lease liabilities	(in KUSD) Lease liabilities Properties (Offices) Vehicles Total January 1, 2021 3,402 65 3,467 Additions 5,662 56 5,718 Cash outflow (including interest) (616) (15) (631) Interest 112 2 114 Exchange difference (66) (2) (68) June 30, 2021 8,494 106 8,600 January 1, 2020 4,953 78 5,031 Cash outflow (including interest) (605) (10) (615) Interest 60 1 61 Exchange difference (45) 1 (44) June 30, 2020 4,363 70 4,433 June 30, 2021 Lease liabilities (short-term) 954 34 988 Lease liabilities (long-term) 7,540 72 7,612 Total lease liabilities 8,494 106 8,600 June 30, 2020 Lease liabilities (short-term) 1,080 19 1,099 Lease liabilities (long-term) 3,283 51 3,334 Total lease liabilities 4,363 70 4,433

Convertible loans (Tables)

Convertible loans (Tables)	6 Months Ended
	Jun. 30, 2021
Financial Instruments [Abstract]
Schedule of key inputs used for valuation	Key inputs for the valuations as of June 30, 2021 and December 31, 2020 were as follows: As of June 30, 2021 December 31, 2020 Exercise price at 130% of the IPO price of 19.00, in USD 24.70 24.70 Forced conversion price, in USD (1) 67.93 67.93 Share price in USD 24.35 32.01 Risk-free interest rate 0.6 % 0.3 % Expected volatility (2) 70 % 90 % Expected term 46 months 52 months Dividend yield — — Recovery rate 5 % 5 % Implied bond yield 8.0 % 13.3 % (1) In accordance with the terms of the convertible loans, under certain circumstances the Company has the right to force conversions of the convertible notes on and after the one- and three-year anniversaries of the date on which it has received regulatory approval of ZYNLONTA as discussed in the Company’s annual report for the period ended December 31, 2020 on Form 20-F. (2) The expected volatility utilized for the June 30, 2021 valuation decreased from that used in the December 31, 2020 valuation due to a change in the peer group. Prior to the FDA approval of ZYNLONTA, the Company utilized a peer group primarily comprised of clinical-stage companies. Upon receipt of FDA approval of ZYNLONTA, the Company updated the peer group to primarily comprise of commercial-stage companies, which lowered the expected volatility assumption utilized in the June 30, 2021 valuation. As of April 23, 2021 December 31, 2020 Exercise price at 150% of the IPO of 19.00, in USD (1) 28.50 28.50 Forced conversion price, in USD (2) 78.38 78.38 Share price in USD (3) 24.85 32.01 Risk-free interest rate 0.6 % 0.3 % Expected volatility 90 % 90 % Expected term 1 month 5 months Dividend yield — — Recovery rate 5 % 5 % Implied bond yield 7.7 % 7.4 % (1) The conversion price for the second tranche of convertible notes is the lesser of (i) 150% of the IPO price and (ii) 120% of the average of the volume-weighted average prices of the Company’s common shares on each of the 15 trading days immediately prior to the disbursement date of the second tranche, but in no event less than a floor equal to 81% of the IPO price. (2) In accordance with the terms of the convertible loans, under certain circumstances the Company has the right to force conversions of the convertible notes on and after the one- and three-year anniversaries of the date on which it received regulatory approval of ZYNLONTA, as discussed in the Company’s annual report for the period ended December 31, 2020 on Form 20-F. (3) The Company utilized the opening share price on April 23, 2021 for the valuation of the derivative immediately prior to FDA approval of ZYNLONTA. As of June 30, 2021 April 23, 2021 Exercise price in USD (1) 28.07 28.50 Forced conversion price, in USD (2) 77.19 78.38 Share price in USD (3) 24.35 23.25 Risk-free interest rate 0.6 % 0.6 % Expected volatility 70 % 75 % Expected term 46 months 48 months Dividend yield — — Recovery rate 5 % 5 % Implied bond yield 8.0 % 6.3 % (1) The conversion price for the second tranche of convertible notes is the lesser of (i) 150% of the IPO price and (ii) 120% of the average of the volume-weighted average prices of the Company’s common shares on each of the 15 trading days immediately prior to the disbursement date of the second tranche, but in no event less than a floor equal to 81% of the IPO price. The conversion price for the second tranche of the convertible notes as of June 30, 2021 was based on 120% of the average of the volume-weighted average process of the Company’s shares on each of the 15 trading days prior to the disbursement date, while the conversion price as of April 23, 2021 was based on 150% of the IPO price. (2) In accordance with the terms of the convertible loans, under certain circumstances the Company has the right to force conversions of the convertible notes on and after the one- and three-year anniversaries of the date on which it received regulatory approval of ZYNLONTA, as discussed in the Company’s annual report for the period ended December 31, 2020 on Form 20-F. (3) The Company utilized the closing share price on April 23, 2021 for the valuation of the embedded conversion option derivative after FDA approval of ZYNLONTA.
Schedule of borrowings	Transaction costs associated with the convertible loan were allocated to the embedded conversion option derivative and residual loan as follows: in KUSD Embedded derivative Residual loan Total Gross proceeds 27,797 37,203 65,000 Less: transaction costs (1,571) (2,102) (3,673) Net 26,226 35,101 61,327

Share-based compensation (Table

Share-based compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangements [Abstract]
Schedule of Shares Outstanding	The following table summarizes the share option awards outstanding as of June 30, 2021: Average strike price per share in USD Number of awards Weighted average remaining life December 31, 2020 26.45 4,276,973 9.29 Granted 28.66 2,077,385 9.69 Forfeited 25.22 (64,933) N/A Expired 18.75 (1,250) N/A Exercised 18.75 (12,519) N/A June 30, 2021 27.21 6,275,656 9.11
Schedule of Fair Value Assumption For Options Granted	The fair values of the options granted during the three and six months ended June 30, 2021 were determined on the date of the grant using the following assumptions: Three Months Ended Six Months Ended June 30, 2021 June 30, 2021 Share price, in USD 22.16 - 25.52 22.16 - 32.22 Strike price, in USD 22.16 - 25.52 22.16 - 32.22 Expected volatility 70% - 85% 70% - 85% Award life 6.08 5.5 - 6.08 Expected dividends — — Risk-free interest rate 1.06% - 1.15% 0.51% - 1.15%
Schedule of Other Equity Instruments Outstanding	Number of awards Weighted average grant date fair value December 31, 2020 149,984 46.50 Granted 412,099 28.70 Forfeited (1,846) N/A June 30, 2021 560,237 33.45
Schedule of Share-based Compensation Reserve	The movement in the Share-based Compensation Reserves (included in Other reserves within equity) is as follows: Three months ended Six months ended (in KUSD) June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Incentive Plan 2014 — 179 — 361 Share Purchase Plan 2016 — 6,425 — 7,417 Equity Incentive Plan 2019 - Share Options 15,315 6,130 28,007 8,746 Equity Incentive Plan 2019 - RSUs 2,952 — 4,211 — Tax and social charge deductions - Incentive Plan 2014 — (5,343) — (5,343) Total 18,267 7,391 32,218 11,181

Related parties (Tables)

Related parties (Tables)	6 Months Ended
	Jun. 30, 2021
Related Party [Abstract]
Key Management Compensation	The compensation of key management is shown below: Three months ended June 30, Six months ended June 30, (in KUSD) 2021 2020 2021 2020 Salaries and other short-term employee costs 1,969 1,666 4,001 3,254 Pension costs 106 107 240 256 Share-based compensation expense 8,604 6,025 13,821 7,599 Other compensation 9 22 22 83 Total 10,688 7,820 18,084 11,192

Loss per share (Tables)

Loss per share (Tables)	6 Months Ended
	Jun. 30, 2021
Earnings per share [abstract]
Schedule of loss per share and potentially dilutive securities	Three Months Ended June 30, Six Months Ended June 30, (in KUSD, except per share amounts) 2021 2020 2021 2020 Loss attributable to owners (72,569) (126,557) (124,096) (170,033) Weighted average number of shares outstanding 76,728,714 62,863,866 76,725,210 57,225,939 Basic and diluted loss per share (0.95) (2.01) (1.62) (2.97) Potentially dilutive securities that were not included in the diluted per share calculations because the effect of including them would be anti-dilutive were as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Equity Incentive Plan 2019 - Share Options 6,258,291 2,784,467 5,475,476 1,999,022 Equity Incentive Plan 2019 - RSUs 560,967 — 379,379 — Conversion of the principal amount of convertible loans into the Company’s common shares 3,982,206 1,766,917 3,310,623 888,340 10,801,464 4,551,384 9,165,478 2,887,362

Corporate information (Details)

Corporate information (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)subsidiary	Dec. 31, 2020USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2019USD ($)
Corporate Information And Statement Of IFRS Compliance [Abstract]
Number of subsidiaries | subsidiary	2
Cash and cash equivalents, minimum quarterly balance	$ 50,000
Cash and cash equivalents	$ 371,884	$ 439,195	$ 348,593	$ 115,551

Basis of preparation - Schedule

Basis of preparation - Schedule of Foreign currency exchange rate (Details) - $ / £	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Corporate Information And Statement Of IFRS Compliance [Abstract]
Closing foreign exchange rate	1.38358	1.23272
Average foreign exchange rate	1.39134	1.23277

Basis of preparation - Addition

Basis of preparation - Additional information (Details) - USD ($)	Jun. 04, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Jun. 30, 2020
Disclosure of associates [line items]
Treasury stock (in shares)		1,548,303		1,548,303
Shares issued (in shares)		1,500,000
Share issue related cost				$ 149,000
Aggregate proceeds				$ 0	$ 244,213,000
ATM Facility
Disclosure of associates [line items]
Aggregate proceeds	$ 200,000,000
Overland ADCT BioPharma
Disclosure of associates [line items]
Proportion of ownership interest in joint venture			49.00%

Basis of preparation - Schedu_2

Basis of preparation - Schedule of consolidated entities (Details)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
ADCT America
Disclosure of subsidiaries [line items]
Consolidated entity ownership	100.00%	100.00%
ADCT UK
Disclosure of subsidiaries [line items]
Consolidated entity ownership	100.00%	100.00%

Significant accounting polici_3

Significant accounting policies (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020
Accounting Policies, Changes in Accounting Estimates And Errors [Abstract]
Gain from reversal of inventory impairment charges	$ 6,752	$ 6,752	$ 0

Financial risk management (Deta

Financial risk management (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)
Volatility Risk
Disclosure of detailed information about financial instruments [line items]
Sensitivity analysis for volatility, reasonably possible change in risk variable	10.00%
Volatility Risk | Disbursement upon completion of IPO
Disclosure of detailed information about financial instruments [line items]
Sensitivity analysis for types of volatility risk, reasonably possible change in risk variable, increase on derivative values	$ 1,248
Sensitivity analysis for types of volatility risk, reasonably possible change in risk variable, decrease on derivative values	1,737
Volatility Risk | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about financial instruments [line items]
Sensitivity analysis for types of volatility risk, reasonably possible change in risk variable, increase on derivative values	1,089
Sensitivity analysis for types of volatility risk, reasonably possible change in risk variable, decrease on derivative values	$ 1,385
Risk-free interest rate | Interest rate risk
Disclosure of detailed information about financial instruments [line items]
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable	10.00%
Risk-free interest rate | Interest rate risk | Disbursement upon completion of IPO
Disclosure of detailed information about financial instruments [line items]
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, increase on derivative values	$ 17
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, decrease on derivative values	17
Risk-free interest rate | Interest rate risk | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about financial instruments [line items]
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, increase on derivative values	14
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, decrease on derivative values	$ 14
Implied bond yield | Interest rate risk
Disclosure of detailed information about financial instruments [line items]
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable	10.00%
Implied bond yield | Interest rate risk | Disbursement upon completion of IPO
Disclosure of detailed information about financial instruments [line items]
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, increase on derivative values	$ 295
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, decrease on derivative values	307
Implied bond yield | Interest rate risk | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about financial instruments [line items]
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, increase on derivative values	171
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, decrease on derivative values	$ 178

Product revenues, net (Details)

Product revenues, net (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Revenue From Contracts With Customers [Abstract]
Sales adjustment, beginning balance	$ 730	$ 0
GTN Sales Adjustment, Provision	752
GTN Sales Adjustment, Credits And Payments	(22)
Sales adjustment, ending balance	730
Accounts receivable, net	533
Other current liabilities	$ 197

Segment information (Details)

Segment information (Details)	6 Months Ended
	Jun. 30, 2021segment
Operating Segments [Abstract]
Number of business segments	1

Expenses by nature - Schedule o

Expenses by nature - Schedule of Expenses by Nature (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disclosure Of Detailed Information About Expenses By Nature [Line Items]
Research and development expense	$ 39,533	$ 25,950	$ 78,705	$ 61,325
Sales and marketing expense	15,221	4,004	29,132	6,632
General and administrative expense	19,367	14,995	36,949	20,877
External costs
Disclosure Of Detailed Information About Expenses By Nature [Line Items]
Research and development expense	21,983	16,161	46,289	42,300
Sales and marketing expense	5,726	2,105	11,016	3,845
General and administrative expense	5,872	2,316	10,605	4,556
Employee expense
Disclosure Of Detailed Information About Expenses By Nature [Line Items]
Research and development expense	17,550	9,789	32,416	19,025
Sales and marketing expense	9,495	1,899	18,116	2,787
General and administrative expense	$ 13,495	$ 12,679	$ 26,344	$ 16,321

Expenses by nature - Narrative

Expenses by nature - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020
Analysis of income and expense [abstract]
Gain from reversal of inventory impairment charges	$ 6,752	$ 6,752	$ 0

Cash and cash equivalents (Deta

Cash and cash equivalents (Details) $ in Millions	Jun. 30, 2021USD ($)
Cash and cash equivalents [abstract]
Cash and cash equivalents, minimum quarterly balance	$ 50

Inventories (Details)

Inventories (Details) $ in Thousands	Jun. 30, 2021USD ($)
Inventory [Abstract]
Current raw materials	$ 0
Current work in progress	7,411
Current finished goods	307
Inventories	$ 7,718

Intangible assets - Rollforward

Intangible assets - Rollforward of Intangible Assets (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Disclosure of detailed information about intangible assets [line items]
Beginning balance	$ 10,179
Ending balance	12,010	$ 8,824
Cost
Disclosure of detailed information about intangible assets [line items]
Beginning balance	11,312	9,368
Additions	1,900	408
Transfers	(6)
Increase (decrease) through net exchange differences, intangible assets other than goodwill		(3)
Ending balance	13,206	9,773
Accumulated amortization
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(1,133)	(934)
Increase (decrease) through net exchange differences, intangible assets other than goodwill		2
Amortisation, intangible assets other than goodwill	(63)	(17)
Ending balance	(1,196)	(949)
Licenses - indefinite lived
Disclosure of detailed information about intangible assets [line items]
Ending balance	10,923	8,743
Licenses - indefinite lived | Cost
Disclosure of detailed information about intangible assets [line items]
Beginning balance	11,144	9,221
Additions	1,300	375
Transfers	(452)
Increase (decrease) through net exchange differences, intangible assets other than goodwill		0
Ending balance	11,992	9,596
Licenses - indefinite lived | Accumulated amortization
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(1,069)	(853)
Increase (decrease) through net exchange differences, intangible assets other than goodwill		0
Amortisation, intangible assets other than goodwill	0	0
Ending balance	(1,069)	(853)
Licenses - definite lived
Disclosure of detailed information about intangible assets [line items]
Ending balance	1,039	0
Licenses - definite lived | Cost
Disclosure of detailed information about intangible assets [line items]
Beginning balance	0	0
Additions	600	0
Transfers	452
Increase (decrease) through net exchange differences, intangible assets other than goodwill		0
Ending balance	1,052	0
Licenses - definite lived | Accumulated amortization
Disclosure of detailed information about intangible assets [line items]
Beginning balance	0	0
Increase (decrease) through net exchange differences, intangible assets other than goodwill		0
Amortisation, intangible assets other than goodwill	(13)	0
Ending balance	(13)	0
Software
Disclosure of detailed information about intangible assets [line items]
Ending balance	48	81
Software | Cost
Disclosure of detailed information about intangible assets [line items]
Beginning balance	168	147
Additions	0	33
Transfers	(6)
Increase (decrease) through net exchange differences, intangible assets other than goodwill		(3)
Ending balance	162	177
Software | Accumulated amortization
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(64)	(81)
Increase (decrease) through net exchange differences, intangible assets other than goodwill		2
Amortisation, intangible assets other than goodwill	(50)	(17)
Ending balance	$ (114)	$ (96)

Intangible assets - Narrative (

Intangible assets - Narrative (Details) - USD ($) $ in Thousands	Apr. 23, 2021	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020
ZYNLONTA
Disclosure of detailed information about intangible assets [line items]
Useful life measured as period of time, intangible assets other than goodwill	14 years
Amortisation, intangible assets other than goodwill		$ 13	$ 13
License To Acquire An Antibody, ZYNLONTA | Milestone Payment
Disclosure of detailed information about intangible assets [line items]
Additions				$ 1,050
License To Use Technology To Generate Antibody Drug Conjugates, ZYNLONTA | Milestone Payment
Disclosure of detailed information about intangible assets [line items]
Additions				600
License To Use Technology To Generate Antibody Drug Conjugates, ZYNLONTA | License Payment
Disclosure of detailed information about intangible assets [line items]
Additions				250
License To Acquire An Antibody | Milestone Payment
Disclosure of detailed information about intangible assets [line items]
Additions				250
License To Use Technology To Generate Antibody Drug Conjugates | Milestone Payment
Disclosure of detailed information about intangible assets [line items]
Additions				$ 125

Interest in joint venture - Nar

Interest in joint venture - Narrative (Details) - Overland ADCT BioPharma	Dec. 14, 2020product
Disclosure of joint ventures [line items]
Number of product candidates developed and commercialized in joint venture	3
Number of products developed and commercialized in joint venture	1

Interest in joint venture - Sch

Interest in joint venture - Schedule of movement in interest in joint venture (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)
Disclosure of joint ventures [line items]
Beginning balance	$ 47,908
Ending balance	46,212
Overland ADCT BioPharma
Disclosure of joint ventures [line items]
Beginning balance	47,908
Share of results in joint venture	(1,696)
Ending balance	$ 46,212

Interest in joint venture - Sum

Interest in joint venture - Summary of financial information in joint venture (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Disclosure of joint ventures [line items]
Cash and cash equivalents	$ 371,884	$ 348,593	$ 371,884	$ 348,593	$ 439,195	$ 115,551
Intangible assets	12,010	8,824	12,010	8,824	10,179
Total liabilities	220,468		220,468		178,187
Operating expense	74,242	44,949	144,907	88,834
Net loss	(72,569)	$ (126,557)	(124,096)	$ (170,033)
Overland ADCT BioPharma
Disclosure of joint ventures [line items]
Cash and cash equivalents	46,636		46,636		50,000
Prepaid and other current assets	111		111		0
Intangible assets	48,040		48,040		48,040
Total liabilities	590		590		269
Net assets	94,197		94,197		$ 97,771
Operating expense	2,493		3,655
Net loss	$ 2,387		$ 3,461

Leases - Narrative (Details)

Leases - Narrative (Details)	3 Months Ended
	Jun. 30, 2021m²
Disclosure of non-adjusting events after reporting period [line items]
Lease area (in square meters)	1,100
Lease term for which payments are fixed	5 years
Lease term	10 years
Minimum
Disclosure of non-adjusting events after reporting period [line items]
Lease rent escalation percent	2.00%
Maximum
Disclosure of non-adjusting events after reporting period [line items]
Lease rent escalation percent	4.00%

Leases - Right-of-Use Assets an

Leases - Right-of-Use Assets and Accumulated Depreciation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			$ 3,129
Depreciation charge	$ (420)	$ (283)	(799)	$ (569)
Right-of-use asset, ending balance	8,077	4,248	8,077	4,248
Cost
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			5,402	5,965
Additions			5,718
Lease termination			(864)
Exchange difference			40	(103)
Right-of-use asset, ending balance	10,296	5,862	10,296	5,862
Accumulated amortization
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			(2,273)	(1,067)
Lease termination			864
Exchange difference			(11)	22
Depreciation charge			(799)	(569)
Right-of-use asset, ending balance	(2,219)	(1,614)	(2,219)	(1,614)
Properties (Offices)
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, ending balance	7,976	4,180	7,976	4,180
Properties (Offices) | Cost
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			5,324	5,887
Additions			5,662
Lease termination			(864)
Exchange difference			40	(103)
Right-of-use asset, ending balance	10,162	5,784	10,162	5,784
Properties (Offices) | Accumulated amortization
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			(2,253)	(1,067)
Lease termination			864
Exchange difference			(11)	22
Depreciation charge			(786)	(559)
Right-of-use asset, ending balance	(2,186)	(1,604)	(2,186)	(1,604)
Vehicles
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, ending balance	101	68	101	68
Vehicles | Cost
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			78	78
Additions			56
Lease termination			0
Exchange difference			0	0
Right-of-use asset, ending balance	134	78	134	78
Vehicles | Accumulated amortization
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			(20)	0
Lease termination			0
Exchange difference			0	0
Depreciation charge			(13)	(10)
Right-of-use asset, ending balance	$ (33)	$ (10)	$ (33)	$ (10)

Leases - Right-of-Use Asset Dep

Leases - Right-of-Use Asset Depreciation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disclosure of quantitative information about right-of-use assets [line items]
Depreciation, right-of-use assets	$ 420	$ 283	$ 799	$ 569
R&D expense
Disclosure of quantitative information about right-of-use assets [line items]
Depreciation, right-of-use assets	358	226	682	453
G&A expense
Disclosure of quantitative information about right-of-use assets [line items]
Depreciation, right-of-use assets	$ 62	$ 57	$ 117	$ 116

Leases - Schedule of Lease Liab

Leases - Schedule of Lease Liabilities (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Disclosure Of Quantitative Information About Lease Liabilities [Line Items]
Beginning balance	$ 3,467	$ 5,031
Additions	5,718
Cash outflow (including interest)	(631)	(615)
Interest	114	61
Exchange difference	(68)	(44)
Ending balance	8,600	4,433
Lease liabilities, short-term	988	1,099	$ 1,002
Lease liabilities, long-term	7,612	3,334	$ 2,465
Properties (Offices)
Disclosure Of Quantitative Information About Lease Liabilities [Line Items]
Beginning balance	3,402	4,953
Additions	5,662
Cash outflow (including interest)	(616)	(605)
Interest	112	60
Exchange difference	(66)	(45)
Ending balance	8,494	4,363
Lease liabilities, short-term	954	1,080
Lease liabilities, long-term	7,540	3,283
Vehicles
Disclosure Of Quantitative Information About Lease Liabilities [Line Items]
Beginning balance	65	78
Additions	56
Cash outflow (including interest)	(15)	(10)
Interest	2	1
Exchange difference	(2)	1
Ending balance	106	70
Lease liabilities, short-term	34	19
Lease liabilities, long-term	$ 72	$ 51

Convertible loans - Narrative (

Convertible loans - Narrative (Details) $ in Thousands	Apr. 23, 2021USD ($)	Apr. 24, 2020USD ($)borrowingComponent	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 04, 2021shares	Dec. 31, 2020USD ($)	May 19, 2020USD ($)
Disclosure of detailed information about borrowings [line items]
Cash and cash equivalents, minimum quarterly balance			$ 50,000		$ 50,000
Convertible loans, derivatives, change in fair value income (expense)			2,053	$ (79,261)	23,222	$ (79,261)
Convertible loans, derivatives			49,619		49,619			$ 73,208
Convertible loans, short-term			$ 6,193		$ 6,193			3,631
Number of shares authorised (in shares) | shares							5,558,318
Facility Agreement with Deerfield Partners, L.P.
Disclosure of detailed information about borrowings [line items]
Borrowings, maximum borrowing capacity		$ 115,000
Number of borrowing components | borrowingComponent		2
Borrowings, interest rate		5.95%	5.95%		5.95%
Exit fee		2.00%
Cash and cash equivalents, minimum quarterly balance		$ 50,000
Loans received			$ 40,493		$ 40,493
Facility Agreement with Deerfield Partners, L.P. | Convertible loan
Disclosure of detailed information about borrowings [line items]
Borrowings, interest rate			5.95%		5.95%
Implied effective interest rate					6.70%
Loans received			$ 50,348		$ 50,348
Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Borrowings		65,000							$ 65,000
Convertible loans, derivatives, change in fair value income (expense)			5,512	57,450	20,780	57,450
Convertible loans, derivatives			30,449		30,449			51,229
Interest expense on borrowings					$ 4,042	2,060
Implied effective interest rate					23.00%
Loans received								38,406
Convertible loans, short-term			3,629		$ 3,629			3,631
Disbursement upon completion of IPO | Convertible loan
Disclosure of detailed information about borrowings [line items]
Interest expense on borrowings				868	390	868
Convertible loans, short-term			2,564		2,564
Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Borrowings		$ 50,000
Convertible loans, derivatives, change in fair value income (expense)			1,012	$ 21,811	1,012	$ 21,811
Convertible loans, derivatives	$ 18,158		19,170		19,170
Loans received								$ 21,979
Proceeds from current borrowings	$ 49,400
Increase (decrease) in credit derivative, fair value			4,263		1,638
Disbursement upon receipt of regulatory approval for ZYNLONTA | Embedded derivative
Disclosure of detailed information about borrowings [line items]
Convertible loans, derivatives, change in fair value income (expense)			$ 1,816		$ 1,816

Convertible loans - Valuation o

Convertible loans - Valuation of Derivative (Details)	May 19, 2020$ / shares	Apr. 24, 2020	Jun. 30, 2021$ / sharesperiod	Apr. 23, 2021$ / sharesperiod	Dec. 31, 2020$ / sharesperiod
Initial Public Offering
Disclosure of detailed information about borrowings [line items]
Offering price per share (in USD per share)	$ 19
Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Conversion percentage			130.00%
Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Average volume weighted price of common shares		120.00%
Floor of IPO price		81.00%
Disbursement upon receipt of regulatory approval for ZYNLONTA | Top of range
Disclosure of detailed information about borrowings [line items]
Conversion percentage		150.00%
Written put options (in USD per share) | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			28.07	28.50
Written put options (in USD per share) | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			24.70		24.70
Written put options (in USD per share) | Derivatives | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations				28.50	28.50
Forced Conversion Price (in USD per share) | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			77.19	78.38
Forced Conversion Price (in USD per share) | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			67.93		67.93
Forced Conversion Price (in USD per share) | Derivatives | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations				78.38	78.38
Share Price (in USD per share) | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			24.35	23.25
Share Price (in USD per share) | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			24.35		32.01
Share Price (in USD per share) | Derivatives | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations				24.85	32.01
Risk-free interest rate | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0.006	0.006
Risk-free interest rate | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0.006		0.003
Risk-free interest rate | Derivatives | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations				0.006	0.003
Expected volatility (2) | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0.70	0.75
Expected volatility (2) | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0.70		0.90
Expected volatility (2) | Derivatives | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations				0.90	0.90
Expected term | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations | period			46	48
Expected term | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations | period			46		52
Expected term | Derivatives | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations | period				1	5
Dividend yield | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0	0
Dividend yield | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0		0
Dividend yield | Derivatives | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations				0	0
Recovery rate | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0.05	0.05
Recovery rate | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0.05		0.05
Recovery rate | Derivatives | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations				0.05	0.05
Implied bond yield | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0.080	0.063
Implied bond yield | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0.080		0.133
Implied bond yield | Derivatives | Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations				0.077	0.074

Convertible loans - Schedule of

Convertible loans - Schedule of the First and Second Tranche (Details) - USD ($) $ in Thousands	May 19, 2020	Apr. 24, 2020
Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Borrowings	$ (65,000)	$ (65,000)
Disbursement upon completion of IPO | Cost
Disclosure of detailed information about borrowings [line items]
Borrowings		(65,000)
Disbursement upon completion of IPO | Cost | Embedded derivative
Disclosure of detailed information about borrowings [line items]
Borrowings		(27,797)
Disbursement upon completion of IPO | Cost | Convertible loan
Disclosure of detailed information about borrowings [line items]
Borrowings		(37,203)
Disbursement upon completion of IPO | Transaction costs
Disclosure of detailed information about borrowings [line items]
Borrowings		(3,673)
Disbursement upon completion of IPO | Transaction costs | Embedded derivative
Disclosure of detailed information about borrowings [line items]
Borrowings		(1,571)
Disbursement upon completion of IPO | Transaction costs | Convertible loan
Disclosure of detailed information about borrowings [line items]
Borrowings		(2,102)
Disbursement upon completion of IPO | Net Carrying Amount
Disclosure of detailed information about borrowings [line items]
Borrowings		(61,327)
Disbursement upon completion of IPO | Net Carrying Amount | Embedded derivative
Disclosure of detailed information about borrowings [line items]
Borrowings		(26,226)
Disbursement upon completion of IPO | Net Carrying Amount | Convertible loan
Disclosure of detailed information about borrowings [line items]
Borrowings		(35,101)
Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Borrowings		(50,000)
Disbursement upon receipt of regulatory approval for ZYNLONTA | Cost
Disclosure of detailed information about borrowings [line items]
Borrowings		(68,526)
Disbursement upon receipt of regulatory approval for ZYNLONTA | Cost | Embedded derivative
Disclosure of detailed information about borrowings [line items]
Borrowings		(18,158)
Disbursement upon receipt of regulatory approval for ZYNLONTA | Cost | Convertible loan
Disclosure of detailed information about borrowings [line items]
Borrowings		(50,368)
Disbursement upon receipt of regulatory approval for ZYNLONTA | Transaction costs
Disclosure of detailed information about borrowings [line items]
Borrowings		(557)
Disbursement upon receipt of regulatory approval for ZYNLONTA | Transaction costs | Embedded derivative
Disclosure of detailed information about borrowings [line items]
Borrowings		(148)
Disbursement upon receipt of regulatory approval for ZYNLONTA | Transaction costs | Convertible loan
Disclosure of detailed information about borrowings [line items]
Borrowings		(409)
Disbursement upon receipt of regulatory approval for ZYNLONTA | Net Carrying Amount | Convertible loan
Disclosure of detailed information about borrowings [line items]
Borrowings		$ (49,959)

Share-based compensation - Narr

Share-based compensation - Narrative (Details) $ / shares in Units, $ in Thousands	Mar. 22, 2021shares	Jun. 30, 2021USD ($)shares$ / shares	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)shares$ / shares	Jun. 30, 2020USD ($)	Mar. 29, 2021shares	Dec. 31, 2020shares	Nov. 30, 2019shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized | $		$ 18,267	$ 7,391	$ 32,218	$ 11,181
Share-based compensation expense | $		$ 18,267	7,391	$ 32,218	11,181
Contractual term				10 years
Number of share options outstanding in share-based payment arrangement (in shares)		6,275,656		6,275,656			4,276,973
Share Options
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period				3 years
Contractual term				10 years
Number of instruments granted in share-based payment arrangement	1,592,651
Weighted-average grant-date fair value (in dollars per share) | $ / shares		$ 20.53
Awards vested and exercisable (in shares)		1,175,927		1,175,927
Weighted average strike price, vested and exercisable (in dollars per share) | $ / shares				$ 20.48
Weighted average remaining life, vested and exercisable				8 years 8 months 19 days
Share Options | Tranche One
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting percentage				25.00%
Share Options | Tranche Two
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting percentage				25.00%
Share Options | Tranche Three
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting percentage				25.00%
Share Options | Tranche Four
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting percentage				25.00%
Restricted Share Units (RSU)
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period				3 years
Shares vested (in shares)				0
Number of instruments granted in share-based payment arrangement	377,255
Incentive Plan 2014
Disclosure of terms and conditions of share-based payment arrangement [line items]
Strike price (in USD per share) | $ / shares				$ 19
Vesting period				4 years
Share-Based Payment Arrangement, Shares Transferred To Participants				356,144
2019 Equity Incentive Plan
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized | $			$ 6,130		$ 8,746
Strike price (in USD per share) | $ / shares				$ 19
Vesting period				3 years
Number of shares reserved for issue under options and contracts for sale of shares		6,996,626		6,996,626		6,000,000		13,820,000
Share-based compensation expense | $				$ 67,716
Share-Based Payment Arrangement, Shares Issued, Tax Withheld | $				5,343
2019 Equity Incentive Plan | Restricted Stock Units
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized | $				$ 2,952

Share-based compensation - Sche

Share-based compensation - Schedule of Number of Awards Outstanding and Weighted Average Strike Price (Details)	3 Months Ended	6 Months Ended
	Mar. 31, 2021shares$ / shares	Jun. 30, 2021shares$ / shares
Share-based Payment Arrangements [Abstract]
Average strike price in USD per share, At beginning of the year (in USD per share) | $ / shares	$ 26.45	$ 26.45
Fair value grant date (in USD per share) | $ / shares		28.66
Average strike price in USD per share, Forfeited (in USD per share) | $ / shares		25.22
Average strike price in USD per share, Expired (in USD per share) | $ / shares		18.75
Average strike price in USD per share, Exercised (in USD per share) | $ / shares		18.75
Average strike price in USD per share, At end of the year (in USD per share) | $ / shares		$ 27.21
Number of awards, At beginning of the year (in shares) | shares	4,276,973	4,276,973
Number of awards, Granted (in shares) | shares		2,077,385
Number of awards, Forfeited (in shares) | shares		(64,933)
Number of awards, Expired (in shares) | shares		(1,250)
Number of awards, Exercised (in shares) | shares		(12,519)
Number of awards, At end of the year (in shares) | shares		6,275,656
Weighted average remaining contractual life of outstanding share options	9 years 3 months 14 days	9 years 1 month 9 days
Weighted average remaining contractual life of granted share options		9 years 8 months 8 days

Share-based compensation expens

Share-based compensation expense - Schedule of Fair Value Assumptions For Options Granted (Details) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2021USD ($)shares$ / shares	Jun. 30, 2021USD ($)shares$ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expected dividends | $	$ 0	$ 0
Minimum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average share price (in USD per share)	$ 22.16	$ 22.16
Strike price (in USD per share)	$ 22.16	$ 22.16
Expected volatility	70.00%	70.00%
Award life | shares	6.08	5.5
Risk-free interest rate	106.00%	0.51%
Maximum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average share price (in USD per share)	$ 25.52	$ 32.22
Strike price (in USD per share)	$ 25.52	$ 32.22
Expected volatility	85.00%	85.00%
Award life | shares		6.08
Risk-free interest rate	1.15%	1.15%

Share-based compensation - Sc_2

Share-based compensation - Schedule of Other Equity Instruments Outstanding (Details)	6 Months Ended
	Jun. 30, 2021shares$ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of awards, forfeited (in shares)	(1,846)
Restricted Share Units (RSU)
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of awards, beginning of period (in shares)	149,984
Number of awards, granted (in shares)	412,099
Number of awards, end of period (in shares)	560,237
Weighted average grant date fair value, beginning balance (in USD per share) | $ / shares	$ 46.50
Weighted average grant date fair value, granted (in USD per share) | $ / shares	28.70
Weighted average grant date fair value, ending balance (in USD per share) | $ / shares	$ 33.45

Share-based compensation - Sc_3

Share-based compensation - Schedule of Share-based Compensation Reserve (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized	$ 18,267	$ 7,391	$ 32,218	$ 11,181
Incentive Plan 2014
Disclosure of terms and conditions of share-based payment arrangement [line items]
Increase in reserve of share-based payments	0	179	0	361
Tax expense from share-based payment transactions with employees	0	(5,343)	0	(5,343)
Share Purchase Plan 2016
Disclosure of terms and conditions of share-based payment arrangement [line items]
Increase in reserve of share-based payments	0	6,425	0	7,417
2019 Equity Incentive Plan
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized		6,130		8,746
2019 Equity Incentive Plan | Share Options
Disclosure of terms and conditions of share-based payment arrangement [line items]
Increase in reserve of share-based payments	15,315	6,130	28,007	8,746
2019 Equity Incentive Plan | Restricted Stock Units
Disclosure of terms and conditions of share-based payment arrangement [line items]
Increase in reserve of share-based payments	$ 2,952	$ 0	4,211	$ 0
Expense recognized			$ 2,952

Related parties - Narrative (De

Related parties - Narrative (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2021USD ($)subsidiary	Jun. 30, 2020USD ($)
Auven Therapeutics Holdings, L.P.
Disclosure of transactions between related parties [line items]
Number of subsidiaries provide services to | subsidiary		3
Services provided to, related party transactions		$ 1	$ 2
Overland ADCT BioPharma
Disclosure of transactions between related parties [line items]
Services provided to, related party transactions	$ 790	$ 790

Related parties - Schedule of K

Related parties - Schedule of Key Management Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Related Party [Abstract]
Salaries and other short-term employee costs	$ 1,969	$ 1,666	$ 4,001	$ 3,254
Pension costs	106	107	240	256
Share-based compensation expense	8,604	6,025	13,821	7,599
Other compensation	9	22	22	83
Key management compensation	$ 10,688	$ 7,820	$ 18,084	$ 11,192

Loss per share (Details)

Loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings per share [abstract]
Net loss	$ (72,569)	$ (126,557)	$ (124,096)	$ (170,033)
Weighted average number of ordinary shares outstanding	76,728,714	62,863,866	76,725,210	57,225,939
Net loss per share, basic and diluted (in USD per share)	$ (0.95)	$ (2.01)	$ (1.62)	$ (2.97)

Loss per share -Schedule of Pot

Loss per share -Schedule of Potentially Dilutive Securities (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings per share [line items]
Potentially dilutive securities	10,801,464	4,551,384
Incentive Plan 2014
Earnings per share [line items]
Potentially dilutive securities			9,165,478	2,887,362
Equity Incentive Plan 2019 - Share Options
Earnings per share [line items]
Potentially dilutive securities	6,258,291	2,784,467	5,475,476	1,999,022
Equity Incentive Plan 2019 - RSUs
Earnings per share [line items]
Potentially dilutive securities	560,967	0	379,379	0
Conversion of the principal amount of convertible loans into the Company’s common shares
Earnings per share [line items]
Potentially dilutive securities	3,982,206	1,766,917	3,310,623	888,340