ADC Therapeutics (ADCT) 6-K 6 May 21 2021 Q1 Condensed Consolidated Interim Statement of Operations Financial data

Cover

Cover	3 Months Ended
	Mar. 31, 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	Mar. 31, 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	Q1

Condensed Consolidated Interim

Condensed Consolidated Interim Statement of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Profit or loss [abstract]
Research and development expenses	$ (39,172)	$ (35,375)
Selling and marketing expenses	(13,911)	(2,628)
General and administrative expenses	(17,582)	(5,882)
Total operating expense	(70,665)	(43,885)
Loss from operations	(70,665)	(43,885)
Other income (expense)
Other income	194	148
Convertible loans, derivatives, change in fair value income	21,169	0
Share of results with joint venture	(527)	0
Financial income	15	374
Financial expense	(2,000)	(42)
Exchange differences	394	29
Total other income	19,245	509
Loss before taxes	(51,420)	(43,376)
Income tax expense	(107)	(100)
Net loss	(51,527)	(43,476)
Net loss attributable to:
Owners of the parent	$ (51,527)	$ (43,476)
Net loss per share
Net loss per share, basic and diluted (in USD per share)	$ (0.67)	$ (0.85)

Condensed Consolidated Interi_2

Condensed Consolidated Interim Statement of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Profit or loss [abstract]
Net loss	$ (51,527)	$ (43,476)
Items that may be reclassified to profit and loss
Currency translation differences	36	(202)
Total items that may be reclassified to profit and loss	36	(202)
Other comprehensive income (loss) for the period	36	(202)
Total comprehensive loss for the period	(51,491)	(43,678)
Total comprehensive loss attributable to:
Owners of the parent	$ (51,491)	$ (43,678)

Condensed Consolidated Interi_3

Condensed Consolidated Interim Balance Sheet - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 383,122	$ 439,195
Other current assets	10,120	11,255
Total current assets	393,242	450,450
Non-current assets
Property, plant and equipment	2,391	1,629
Right-of-use assets	8,152	3,129
Intangible assets	10,147	10,179
Interest in joint venture	47,381	47,908
Other long-term assets	392	397
Total non-current assets	68,463	63,242
Total assets	461,705	513,692
Current liabilities
Accounts payable	11,462	5,279
Other current liabilities	25,272	30,375
Lease liabilities, short-term	833	1,002
Current income tax payable	237	149
Convertible loans, short-term	3,594	3,631
Total current liabilities	41,398	40,436
Non-current liabilities
Convertible loans, long-term	35,773	34,775
Convertible loans, derivatives	52,039	73,208
Deferred gain of joint venture	23,539	23,539
Lease liabilities, long-term	7,599	2,465
Defined benefit pension liabilities	3,389	3,543
Other non-current liabilities	0	221
Total non-current liabilities	122,339	137,751
Total liabilities	163,737	178,187
Equity attributable to owners of the parent
Share capital	6,314	6,314
Share premium	981,059	981,056
Treasury shares	(4)	(4)
Other reserves	56,704	42,753
Cumulative translation adjustments	281	245
Accumulated losses	(746,386)	(694,859)
Total equity attributable to owners of the parent	297,968	335,505
Total liabilities and equity	$ 461,705	$ 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	(43,476)						(43,476)
Translation adjustment	(202)					(202)
Other comprehensive income (loss) for the period	(202)					(202)
Total comprehensive loss for the period	(43,678)					(202)	(43,476)
Share-based compensation expense	3,790			3,790
Total transactions with owners	3,790			3,790
Equity, ending balance at Mar. 31, 2020	71,268	4,361	549,922	9,263	(100)	(133)	(492,045)
Equity, beginning balance at Dec. 31, 2020	335,505	6,314	981,056	42,753	(4)	245	(694,859)
Loss for the period	(51,527)						(51,527)
Translation adjustment	36					36
Other comprehensive income (loss) for the period	36					36
Total comprehensive loss for the period	(51,491)					36	(51,527)
Exercise of options	3		3
Share-based compensation expense	13,951			13,951
Total transactions with owners	13,954		3	13,951
Equity, ending balance at Mar. 31, 2021	$ 297,968	$ 6,314	$ 981,059	$ 56,704	$ (4)	$ 281	$ (746,386)

Condensed Consolidated Interi_5

Condensed Consolidated Interim Statement of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash used in operating activities
Loss for the period	$ (51,527)	$ (43,476)
Adjustments for non-monetary items:
Share-based compensation expense	13,951	3,790
Depreciation of property, plant and equipment	174	148
Amortization of intangible assets	25	9
Depreciation of right-of-use assets	379	286
Share of results with joint venture	527	0
Change in defined benefit pension liability	74	94
Convertible loans, derivatives, increase in fair value	(21,169)	0
Financial income	(15)	(374)
Financial expense	1,982	11
Exchange differences	(366)	(8)
Income taxes	107	100
Operating loss before working capital changes	(55,858)	(39,420)
Increase in accounts receivable	0	(1)
Decrease in other assets	1,075	1,430
Increase in accounts payable	5,914	5,282
(Decrease) increase in other liabilities	(5,332)	242
Cash used in operating activities	(54,201)	(32,467)
Interest paid	(1,039)	(42)
Interest received	16	374
Interest expense on lease obligations	18	31
Tax refund	57	2
Net cash used in operating activities	(55,149)	(32,102)
Cash used in investing activities
Payment for purchase of property, plant and equipment	(657)	(101)
Payment for purchase of intangible assets	0	(375)
Payment for rent deposits	0	(20)
Net cash used in investing activities	(657)	(496)
Cash from financing activities
Proceeds from the exercise of stock options	3	0
Principal portion of lease obligation payments	(300)	(278)
Net cash from financing activities	(297)	(278)
Net decrease in cash and cash equivalents	(56,103)	(32,876)
Exchange gain / (losses) on cash and cash equivalents	30	(100)
Cash and cash equivalents at beginning of the period	439,195	115,551
Cash and cash equivalents at end of the period	383,122	82,575
Supplemental Non-Cash Investing Information
Capital expenditures recorded in Accounts payable	$ 265	$ 0

Corporate information

Corporate information	3 Months Ended
	Mar. 31, 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. 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 May 6, 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 11, “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 March 31, 2021, the Group’s cash and cash equivalents amounted to USD 383.1 million (December 31, 2020: USD 439.2 million). The Board of Directors 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. As the Group advances its clinical programs, it 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. In light of recent developments relating to the COVID-19 pandemic, the primary focus of healthcare providers and hospitals is currently on fighting the novel coronavirus. In addition, in response to the spread of COVID-19, the Group has modified its business practices, including restricting employee travel, developing social distancing plans for its employees and cancelling physical participation in meetings, events and conferences. In addition, certain of the Group’s clinical trials experienced delays or suspensions in patient

Basis of preparation

Basis of preparation	3 Months Ended
	Mar. 31, 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 months ended March 31, 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: Three Months Ended March 31, 2021 2020 USD / GBP Closing rate, GBP 1 1.37665 1.23746 Weighted average exchange rate, GBP 1 1.38246 1.26382 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 2020 which the Company accounts for under the equity method of accounting (see note 9,“Interest in Joint Venture”). The consolidated entities include: Ownership Interest March 31, 2021 March 31, 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. Share split and share consolidation On September 19, 2019, the Company effected a one-to-15,625 share split of its outstanding shares and, on April 24, 2020, the Company effected a five-for-four consolidation of its outstanding shares. Accordingly, all share and per share amounts for all periods presented in these unaudited condensed consolidated interim financial statements and notes thereto have been adjusted retroactively to reflect the share split and share consolidation. Selling and marketing ( “ S&M ” ) expenses

Significant accounting policies

Significant accounting policies	3 Months Ended
	Mar. 31, 2021
Accounting Policies, Changes in Accounting Estimates And Errors [Abstract]
Significant accounting policies	Significant accounting policies The 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. Revenue Recognition To date, the Company has not generated any revenue from the sale of its product candidates. In previous years, the Company had generated service revenues from a license and collaboration arrangement. On April 23, 2021, the U.S. Food and Drug Administration (“FDA”) approved the commercial use of ZYNLONTA for the treatment of relapsed or refractory diffuse large B-cell lymphoma. The Company has developed its revenue recognition policy for the sale of products. Revenue from the sale of products will be 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 will follow 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 will also be reduced for gross-to-net (“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. At launch, the Company will also use 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. 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	3 Months Ended
	Mar. 31, 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 changes in financial risk management since year-end. 4.2 Fair value estimation At March 31, 2021, the carrying amount is a reasonable approximation of fair value for the following financial assets and liabilities: • Cash and cash equivalents • Trade accounts payable In the three months ended March 31, 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 on an ongoing basis with regard to awards under the ADC Therapeutics SA 2019 Equity Incentive Plan (the “Equity Incentive Plan 2019”), with regard to the convertible loan conversion option derivative related to the first tranche of the convertible loans and with regard to the derivative arising from the obligation related to the 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 12, “Share-based compensation” and for the convertible loan derivatives in note 11, “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 derivative relating to the 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 and the derivative associated with the first and second tranche of the Company’s convertible loans (see note 11, “Convertible loans”), respectively, 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 derivative and derivative. A hypothetical 10% increase (decrease) in the risk free rate as of March 31, 2021 would have increased (decreased) the derivative values associated with the first and second tranche of our convertible loans by KUSD 15 (KUSD 13) and KUSD 10 (KUSD 9), respectively. A hypothetical 10% increase (decrease) in the implied bond yield as of March 31, 2021 would have increased (decreased) the derivative value associated with the first tranche of our convertible loans by KUSD 456 and (KUSD 513) and (decreased) increased the derivative value associated with the second tranche of our convertible loans by (KUSD 958) and KUSD 892. A hypothetical 10% increase (decrease) in the selected volatility as of March 31, 2021 would have increased (decreased) the derivative value associated with the first tranche of our convertible loans by KUSD 1,442 (KUSD 1,052) and increased (decreased) the derivative value associated with the second tranche of our convertible loans by KUSD 309 and (KUSD 761).

Segment information

Segment information	3 Months Ended
	Mar. 31, 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	3 Months Ended
	Mar. 31, 2021
Analysis of income and expense [abstract]
Expenses by nature	Expenses by nature The following table summarizes Research and development expenses (“R&D”), S&M expenses and G&A expenses for the three months ended March 31, 2021 and 2020: (in KUSD) Three months ended March 31, R&D 2021 2020 External costs (1) 24,306 26,139 Employee expense (2) 14,866 9,236 R&D expenses 39,172 35,375 S&M External costs 5,290 1,740 Employee expense (2) 8,621 888 S&M expenses 13,911 2,628 G&A External costs (1) 4,733 2,240 Employee expense (2) 12,849 3,642 G&A expenses 17,582 5,882 (1) Includes depreciation expense (2) Includes share-based compensation expense The increase in R&D expenses in the three months ended March 31, 2021 was primarily associated with the increased number of R&D employees necessary to advance its lead product candidates which also contributed to increased share-based compensation expense. This increase was partially offset by lower External costs primarily related to decreased expense associated with clinical activities and chemistry, manufacturing and controls (“CMC”) due to various development activities that occurred during the three months ended March 31, 2020.

Cash and cash equivalents

Cash and cash equivalents	3 Months Ended
	Mar. 31, 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 11, “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 condensed consolidated interim balance sheet.

Intangible assets

Intangible assets	3 Months Ended
	Mar. 31, 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. As at March 31, 2021, the Company had not received any regulatory and marketing approval for any of its product candidates and therefore classified all of its licenses as indefinite-lived intangible assets. Consequently, the Company did not recognize any amortization expense of licenses. During the three months ended March 31, 2021, the Company did not capitalize any license payments as intangible assets. During the three months ended March 31, 2020, the Company capitalized the following license payments as intangible assets: • An amount of KUSD 250 relating to a license agreement with a third party to acquire an antibody to be used in research, development, manufacturing and commercialization; and • An amount of KUSD 125 relating to a license agreement with a third party to use their technology to generate antibody-drug conjugates.

Interest in joint venture

Interest in joint venture	3 Months Ended
	Mar. 31, 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 March 31, 2021. (in KUSD) Interest in joint venture January 1, 2021 47,908 Share of results in joint venture (527) March 31, 2021 47,381 As of March 31, 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 March 31, 2021 December 31, 2020 Cash and cash equivalents 49,013 50,000 Intangible assets 48,040 48,040 Total liabilities 441 269 Net assets 96,696 97,771 Summarized Statement of Comprehensive Loss Three months ended March 31, 2021 Operating expenses 1,162 Net loss 1,074

Leases

Leases	3 Months Ended
	Mar. 31, 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. (in KUSD) Right-of-Use Assets Properties (Offices) Vehicles Total Cost January 1, 2020 5,887 78 5,965 Exchange difference (97) — (97) March 31, 2020 5,790 78 5,868 January 1, 2021 5,324 78 5,402 Additions 5,345 56 5,401 Exchange difference 9 — 9 March 31, 2021 10,678 134 10,812 Accumulated depreciation January 1, 2020 (1,067) — (1,067) Depreciation charge (280) (6) (286) Exchange difference 21 — 21 March 31, 2020 (1,326) (6) (1,332) January 1, 2021 (2,253) (20) (2,273) Depreciation charge (374) (5) (379) Exchange difference (8) — (8) March 31, 2021 (2,635) (25) (2,660) Net book amount March 31, 2020 4,464 72 4,536 March 31, 2021 8,043 109 8,152 Depreciation of right-of-use assets have been charged to the following categories in the condensed consolidated statement of operations: Three months ended March 31, (in KUSD) 2021 2020 R&D expenses 324 227 G&A expenses 55 59 379 286 (in KUSD) Lease liabilities Properties (Offices) Vehicles Total January 1, 2020 4,953 78 5,031 Cash outflow (including interest) (304) (5) (309) Interest 30 1 31 Exchange difference (66) — (66) March 31, 2020 4,613 74 4,687 January 1, 2021 3,402 65 3,467 Additions 5,345 56 5,401 Cash outflow (including interest) (313) (5) (318) Interest 18 — 18 Exchange difference (133) (3) (136) March 31, 2021 8,319 113 8,432 March 31, 2020 Lease liabilities (short-term) 1,103 19 1,122 Lease liabilities (long-term) 3,510 55 3,565 Total lease liabilities 4,613 74 4,687 March 31, 2021 Lease liabilities (short-term) 799 34 833 Lease liabilities (long-term) 7,520 79 7,599 Total lease liabilities 8,319 113 8,432

Convertible loans

Convertible loans	3 Months Ended
	Mar. 31, 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”). See note 15, “Events after the reporting date” for further information. 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. 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. 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 disclosed 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 months ended March 31, 2021, the Company recognized income of KUSD 15,268 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 35,961 and KUSD 51,229 as of March 31, 2021 and December 31, 2020, respectively. The decrease in fair value of the embedded derivative during the three months ended March 31, 2021 is primarily due to the decrease in the fair value of the underlying shares from December 31, 2020 to March 31, 2021, which was charged directly to the unaudited condensed consolidated interim statement of operations. The Company has 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 March 31, 2021 and December 31, 2020 were as follows: As of March 31, 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 24.41 32.01 Risk-free interest rate 0.7 % 0.3 % Expected volatility 90 % 90 % Expected term 49 months 52 months Dividend yield — — Recovery rate 5 % 5 % Implied bond yield 12.5 % 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 disclosed in the Company annual report for the period ended December 31, 2020 on Form 20-F. 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 months ended March 31, 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 1,982 based on the implied effective interest rate, was computed at inception at 23%. The amount at which the convertible loan is presented as a liability in the interim condensed consolidated 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 39,367 as of March 31, 2021, of which KUSD 3,594 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 - subsequent disbursement of convertible loans The Company is obligated to draw down the second tranche upon receipt of regulatory approval for ZYNLONTA. Prior to drawing down the second tranche, the obligation to do so under the terms specified in the Facility Agreement was accounted for as a derivative, which the Company marked-to-market quarterly. During the three months ended March 31, 2021, the Company recognized income of KUSD 5,901 as a result of changes in the fair value of the derivative. The fair value of the derivative associated with the second tranche was KUSD 16,078 and KUSD 21,979 as of March 31, 2021 and December 31, 2020, respectively, which was presented as a financial liability in the unaudited condensed consolidated interim balance sheet. The decrease in fair value of the derivative during the three months ended March 31, 2021 is primarily due to the decrease in the fair value of the underlying shares from December 31, 2020 to March 31, 2021, which was charged directly to the unaudited condensed consolidated interim statement of operations. The Company has used an independent valuation firm to assist in calculating the fair value of the 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 valuation as of March 31, 2021 were as follows: As of March 31, 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 24.41 32.01 Risk-free interest rate 0.7 % 0.3 % Expected volatility 90 % 90 % Expected term 2 months 5 months Dividend yield — — Recovery rate 5 % 5 % Implied bond yield 7.9 % 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. If the conversion price of the second tranche of convertible notes is less than the floor price but for the application of the floor, Deerfield will not be obligated to extend the second tranche. (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. In addition to the key inputs disclosed above for the second tranche, the Company estimated the probability of achieving regulatory approval for ZYNLONTA. For purposes of its March 31, 2021 valuation, the Company estimated it was highly probable that it would receive regulatory approval for ZYNLONTA.

Share-based compensation

Share-based compensation	3 Months Ended
	Mar. 31, 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 months ended March 31, 2021 and 2020 are nil and KUSD 992, respectively. 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. 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 months ended March 31, 2021 and 2020 are nil and KUSD 182, 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 7,820,000 common shares for future issuance under the Equity Incentive Plan 2019, which include common shares pursuant to share-based equity awards issued to date. As of March 31, 2021, the Company has 1,063,893 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 March 31, 2021, the Company has only granted share options and RSUs under the Equity Incentive Plan 2019. As of March 31, 2021, the cumulative amount recorded as an increase to Other Reserves within equity on the unaudited condensed consolidated interim balance sheet of the Equity Incentive Plan 2019 was KUSD 49,449. The amount of expense for all awards recognized for services received during the three months ended March 31, 2021 and 2020 were KUSD 13,951 and KUSD 2,616 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 months ended March 31, 2021, and 2020 is KUSD 12,692 and KUSD 2,616, respectively. The following table summarizes the share option awards outstanding as of March 31, 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 28.92 1,958,246 9.93 Forfeited 21.73 (44,090) N/A Exercised 18.75 (155) N/A March 31, 2021 27.27 6,190,974 9.35 Awards outstanding as of March 31, 2021 and December 31, 2020, expire through 2031. No awards have expired. The options granted during the quarter ended March 31, 2021, primarily related to the Company's first annual equity award of 1,592,651 options. The weighted-average grant-date fair value of these options was USD 20.53 per share. As of March 31, 2021, 679,874 awards are vested and exercisable out of the total outstanding awards of 6,190,974 common shares. The weighted average strike price and weighted average remaining life for vested and exercisable awards is USD 18.75 and 8.91 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 has 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 months ended March 31, 2021 were determined on the date of the grant using the following assumptions: Three Months Ended March 31, 2021 Share price $27.32 - $32.22 Strike price $27.32 - $32.22 Expected volatility 85% Award life 5.50-6.08 Expected dividends 0% Risk-free interest rate 0.51% - 1.12% 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 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 months ended March 31, 2021, and 2020 is KUSD 1,259 and KUSD nil, respectively. Number of awards Weighted average grant date fair value December 31, 2020 149,984 46.50 Granted 412,099 28.70 March 31, 2021 562,083 33.45 The RSUs granted during the quarter primarily related to the first annual equity award. There were no vested RSUs during the three months ended March 31, 2021. Share-based Compensation Reserves The movement in the Share-based Compensation Reserves (included in Other reserves within equity) is as follows: Three months ended (in KUSD) March 31, 2021 March 31, 2020 Incentive Plan 2014 — 182 Share Purchase Plan 2016 — 992 Equity Incentive Plan 2019 - Share Options 12,692 2,616 Equity Incentive Plan 2019 - RSUs 1,259 — Total 13,951 3,790

Related parties

Related parties	3 Months Ended
	Mar. 31, 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”). Services provided by the Company The Company provides registered office and other simple administrative services to three subsidiaries of ATH. The amounts invoiced for three months ended March 31, 2021 and recovered through G&A expenses, amounted to KUSD 1 (three months ended March 31, 2020: KUSD 1). Key management compensation The compensation of key management is shown below: Three months ended March 31, (in KUSD) 2021 2020 Salaries and other short-term employee costs 2,032 1,605 Pension costs 134 149 Share-based compensation expense 5,217 1,581 Other compensation 13 62 Total 7,396 3,397

Loss per share

Loss per share	3 Months Ended
	Mar. 31, 2021
Earnings per share [abstract]
Loss per share	Loss per share Three Months Ended March 31, (in KUSD, except per share amounts) 2021 2020 Loss attributable to owners (51,527) (43,476) Weighted average number of shares outstanding 1 76,721,667 50,959,156 Basic and diluted loss per share (0.67) (0.85) 1 Share data have been revised to give effect to the share split and share consolidation as explained in note 2, “Share split and share consolidation” As all Class B, C, D and E preferred shares were converted into common shares upon the completion of the IPO, loss per share data are presented on that basis for all periods. For the three months ended March 31, 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 March 31, 2021 2020 Incentive Plan 2014 — 2,183,856 Share Purchase Plan 2016 — 3,346,960 Equity Incentive Plan 2019 - Share Options - Share Options 4,683,132 1,017,294 Equity Incentive Plan 2019 - RSUs 195,773 — Conversion of the principal amount of convertible loans into the Company’s common shares 2,631,579 — 7,510,484 6,548,110

Events after the reporting date

Events after the reporting date	3 Months Ended
	Mar. 31, 2021
Events After Reporting Period [Abstract]
Events after the reporting date	Events after the reporting date The Company has evaluated its subsequent events through May 6, 2021, the date the unaudited condensed consolidated interim financial statements were available to be issued other than those described below. On April 23, 2021, the FDA approved the commercial use of ZYNLONTA for the treatment of relapsed or refractory diffuse large B-cell lymphoma. The Company believes that it has sufficient commercial-grade drug product in stock for the foreseeable future and has plans in place with its contract manufacturing organizations to conduct additional manufacturing at the appropriate time . Prior to regulatory approval, the Company had written down its inventory costs related to the manufacture of ZYNLONTA to a net realizable value of zero. However, in accordance with International Accounting Standard 2 Inventories (“IAS 2”), the Company anticipates reversing previously recorded impairment charges of approximately USD 7 million to USD 8 million during the second quarter of fiscal year 2021 based on a number of factors existing at that time, including the existence of inventory on hand and estimated demand as well as the expiration of such product. The reversal of impairment charges will be recorded as income to research and development expenses in the Company’s 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.

Significant accounting polici_2

Significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 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 months ended March 31, 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 To date, the Company has not generated any revenue from the sale of its product candidates. In previous years, the Company had generated service revenues from a license and collaboration arrangement. On April 23, 2021, the U.S. Food and Drug Administration (“FDA”) approved the commercial use of ZYNLONTA for the treatment of relapsed or refractory diffuse large B-cell lymphoma. The Company has developed its revenue recognition policy for the sale of products. Revenue from the sale of products will be 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 will follow 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 will also be reduced for gross-to-net (“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. At launch, the Company will also use 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)	3 Months Ended
	Mar. 31, 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: Three Months Ended March 31, 2021 2020 USD / GBP Closing rate, GBP 1 1.37665 1.23746 Weighted average exchange rate, GBP 1 1.38246 1.26382 Basis of Consolidation
Schedule of consolidated entities	The consolidated entities include: Ownership Interest March 31, 2021 March 31, 2020 ADCT America 100 % 100 % ADCT UK 100 % 100 %

Expenses by nature (Tables)

Expenses by nature (Tables)	3 Months Ended
	Mar. 31, 2021
Analysis of income and expense [abstract]
Disclosure Of Detailed Information About Expenses By Nature Explanatory	The following table summarizes Research and development expenses (“R&D”), S&M expenses and G&A expenses for the three months ended March 31, 2021 and 2020: (in KUSD) Three months ended March 31, R&D 2021 2020 External costs (1) 24,306 26,139 Employee expense (2) 14,866 9,236 R&D expenses 39,172 35,375 S&M External costs 5,290 1,740 Employee expense (2) 8,621 888 S&M expenses 13,911 2,628 G&A External costs (1) 4,733 2,240 Employee expense (2) 12,849 3,642 G&A expenses 17,582 5,882 (1) Includes depreciation expense (2) Includes share-based compensation expense

Interest in joint venture (Tabl

Interest in joint venture (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2021. (in KUSD) Interest in joint venture January 1, 2021 47,908 Share of results in joint venture (527) March 31, 2021 47,381
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 March 31, 2021 December 31, 2020 Cash and cash equivalents 49,013 50,000 Intangible assets 48,040 48,040 Total liabilities 441 269 Net assets 96,696 97,771 Summarized Statement of Comprehensive Loss Three months ended March 31, 2021 Operating expenses 1,162 Net loss 1,074

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 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, 2020 5,887 78 5,965 Exchange difference (97) — (97) March 31, 2020 5,790 78 5,868 January 1, 2021 5,324 78 5,402 Additions 5,345 56 5,401 Exchange difference 9 — 9 March 31, 2021 10,678 134 10,812 Accumulated depreciation January 1, 2020 (1,067) — (1,067) Depreciation charge (280) (6) (286) Exchange difference 21 — 21 March 31, 2020 (1,326) (6) (1,332) January 1, 2021 (2,253) (20) (2,273) Depreciation charge (374) (5) (379) Exchange difference (8) — (8) March 31, 2021 (2,635) (25) (2,660) Net book amount March 31, 2020 4,464 72 4,536 March 31, 2021 8,043 109 8,152 Depreciation of right-of-use assets have been charged to the following categories in the condensed consolidated statement of operations: Three months ended March 31, (in KUSD) 2021 2020 R&D expenses 324 227 G&A expenses 55 59 379 286
Schedule of quantitative information about lease liabilities	(in KUSD) Lease liabilities Properties (Offices) Vehicles Total January 1, 2020 4,953 78 5,031 Cash outflow (including interest) (304) (5) (309) Interest 30 1 31 Exchange difference (66) — (66) March 31, 2020 4,613 74 4,687 January 1, 2021 3,402 65 3,467 Additions 5,345 56 5,401 Cash outflow (including interest) (313) (5) (318) Interest 18 — 18 Exchange difference (133) (3) (136) March 31, 2021 8,319 113 8,432 March 31, 2020 Lease liabilities (short-term) 1,103 19 1,122 Lease liabilities (long-term) 3,510 55 3,565 Total lease liabilities 4,613 74 4,687 March 31, 2021 Lease liabilities (short-term) 799 34 833 Lease liabilities (long-term) 7,520 79 7,599 Total lease liabilities 8,319 113 8,432

Convertible loans (Tables)

Convertible loans (Tables)	3 Months Ended
	Mar. 31, 2021
Financial Instruments [Abstract]
Schedule of key inputs used for valuation	Key inputs for the valuations as of March 31, 2021 and December 31, 2020 were as follows: As of March 31, 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 24.41 32.01 Risk-free interest rate 0.7 % 0.3 % Expected volatility 90 % 90 % Expected term 49 months 52 months Dividend yield — — Recovery rate 5 % 5 % Implied bond yield 12.5 % 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 disclosed in the Company annual report for the period ended December 31, 2020 on Form 20-F. As of March 31, 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 24.41 32.01 Risk-free interest rate 0.7 % 0.3 % Expected volatility 90 % 90 % Expected term 2 months 5 months Dividend yield — — Recovery rate 5 % 5 % Implied bond yield 7.9 % 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. If the conversion price of the second tranche of convertible notes is less than the floor price but for the application of the floor, Deerfield will not be obligated to extend the second tranche.

Share-based compensation (Table

Share-based compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangements [Abstract]
Schedule of Shares Outstanding	The following table summarizes the share option awards outstanding as of March 31, 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 28.92 1,958,246 9.93 Forfeited 21.73 (44,090) N/A Exercised 18.75 (155) N/A March 31, 2021 27.27 6,190,974 9.35
Schedule of Fair Value Assumption For Options Granted	The fair values of the options granted during the three months ended March 31, 2021 were determined on the date of the grant using the following assumptions: Three Months Ended March 31, 2021 Share price $27.32 - $32.22 Strike price $27.32 - $32.22 Expected volatility 85% Award life 5.50-6.08 Expected dividends 0% Risk-free interest rate 0.51% - 1.12%
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 March 31, 2021 562,083 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 (in KUSD) March 31, 2021 March 31, 2020 Incentive Plan 2014 — 182 Share Purchase Plan 2016 — 992 Equity Incentive Plan 2019 - Share Options 12,692 2,616 Equity Incentive Plan 2019 - RSUs 1,259 — Total 13,951 3,790

Related parties (Tables)

Related parties (Tables)	3 Months Ended
	Mar. 31, 2021
Related Party [Abstract]
Key Management Compensation	The compensation of key management is shown below: Three months ended March 31, (in KUSD) 2021 2020 Salaries and other short-term employee costs 2,032 1,605 Pension costs 134 149 Share-based compensation expense 5,217 1,581 Other compensation 13 62 Total 7,396 3,397

Loss per share (Tables)

Loss per share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings per share [abstract]
Schedule of loss per share and potentially dilutive securities	Three Months Ended March 31, (in KUSD, except per share amounts) 2021 2020 Loss attributable to owners (51,527) (43,476) Weighted average number of shares outstanding 1 76,721,667 50,959,156 Basic and diluted loss per share (0.67) (0.85) 1 Share data have been revised to give effect to the share split and share consolidation as explained in note 2, “Share split and share consolidation” 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 March 31, 2021 2020 Incentive Plan 2014 — 2,183,856 Share Purchase Plan 2016 — 3,346,960 Equity Incentive Plan 2019 - Share Options - Share Options 4,683,132 1,017,294 Equity Incentive Plan 2019 - RSUs 195,773 — Conversion of the principal amount of convertible loans into the Company’s common shares 2,631,579 — 7,510,484 6,548,110

Corporate information (Details)

Corporate information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)subsidiary	Dec. 31, 2020USD ($)	Mar. 31, 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	$ 383,122	$ 439,195	$ 82,575	$ 115,551

Basis of preparation - Schedule

Basis of preparation - Schedule of Foreign currency exchange rate (Details) - $ / £	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Corporate Information And Statement Of IFRS Compliance [Abstract]
Closing foreign exchange rate	1.37665	1.23746
Average foreign exchange rate	1.38246	1.26382

Basis of preparation - Addition

Basis of preparation - Additional information (Details)	Apr. 24, 2020	Sep. 19, 2019	Dec. 31, 2020
Disclosure of associates [line items]
Stock split conversion ratio		0.000064
Share consolidation ratio	0.8
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)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 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%

Financial risk management (Deta

Financial risk management (Details) $ in Thousands	3 Months Ended
	Mar. 31, 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	$ 1,442
Sensitivity analysis for types of volatility risk, reasonably possible change in risk variable, decrease on derivative values	1,052
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	761
Sensitivity analysis for types of volatility risk, reasonably possible change in risk variable, decrease on derivative values	$ 309
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	$ 15
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, decrease on derivative values	13
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	10
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, decrease on derivative values	$ 9
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	$ 456
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, decrease on derivative values	513
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	892
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, decrease on derivative values	$ 958

Segment information (Details)

Segment information (Details)	3 Months Ended
	Mar. 31, 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
	Mar. 31, 2021	Mar. 31, 2020
Disclosure Of Detailed Information About Expenses By Nature [Line Items]
Research and development expense	$ 39,172	$ 35,375
Sales and marketing expense	13,911	2,628
General and administrative expense	17,582	5,882
External costs
Disclosure Of Detailed Information About Expenses By Nature [Line Items]
Research and development expense	24,306	26,139
Sales and marketing expense	5,290	1,740
General and administrative expense	4,733	2,240
Employee expense
Disclosure Of Detailed Information About Expenses By Nature [Line Items]
Research and development expense	14,866	9,236
Sales and marketing expense	8,621	888
General and administrative expense	$ 12,849	$ 3,642

Cash and cash equivalents (Deta

Cash and cash equivalents (Details) $ in Millions	Mar. 31, 2021USD ($)
Cash and cash equivalents [abstract]
Cash and cash equivalents, minimum quarterly balance	$ 50

Intangible assets (Details)

Intangible assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disclosure of detailed information about intangible assets [line items]
Additions	$ 0
License To Acquire An Antibody
Disclosure of detailed information about intangible assets [line items]
Additions		$ 250
License To Use Technology To Generate Antibody Drug Conjugates
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	3 Months Ended
	Mar. 31, 2021USD ($)
Disclosure of joint ventures [line items]
Beginning balance	$ 47,908
Ending balance	47,381
Overland ADCT BioPharma
Disclosure of joint ventures [line items]
Beginning balance	47,908
Share of results in joint venture	(527)
Ending balance	$ 47,381

Interest in joint venture - Sum

Interest in joint venture - Summary of financial information in joint venture (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Disclosure of joint ventures [line items]
Cash and cash equivalents	$ 383,122	$ 82,575	$ 439,195	$ 115,551
Intangible assets	10,147		10,179
Total liabilities	163,737		178,187
Operating expense	70,665	43,885
Net loss	(51,527)	$ (43,476)
Overland ADCT BioPharma
Disclosure of joint ventures [line items]
Cash and cash equivalents	49,013		50,000
Intangible assets	48,040		48,040
Total liabilities	441		269
Net assets	96,696		$ 97,771
Operating expense	1,162
Net loss	$ 1,074

Leases - Narrative (Details)

Leases - Narrative (Details)	3 Months Ended
	Mar. 31, 2021m²
Disclosure of non-adjusting events after reporting period [line items]
Lease term	10 years
Lease area (in square meters)	1,100
Lease term for which payments are fixed	5 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
	Mar. 31, 2021	Mar. 31, 2020
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance	$ 3,129
Depreciation, right-of-use assets	(379)	$ (286)
Right-of-use asset, ending balance	8,152	4,536
Cost
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance	5,402	5,965
Additions	5,401
Exchange differences, right-of-use-assets	9	(97)
Right-of-use asset, ending balance	10,812	5,868
Accumulated amortization
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance	(2,273)	(1,067)
Exchange differences, right-of-use-assets	(8)	21
Depreciation, right-of-use assets	(379)	(286)
Right-of-use asset, ending balance	(2,660)	(1,332)
Properties (Offices)
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, ending balance	8,043	4,464
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	5,345
Exchange differences, right-of-use-assets	9	(97)
Right-of-use asset, ending balance	10,678	5,790
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)
Exchange differences, right-of-use-assets	(8)	21
Depreciation, right-of-use assets	(374)	(280)
Right-of-use asset, ending balance	(2,635)	(1,326)
Vehicles
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, ending balance	109	72
Vehicles | Cost
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance	78	78
Additions	56
Exchange differences, right-of-use-assets	0	0
Right-of-use asset, ending balance	134	78
Vehicles | Accumulated amortization
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance	(20)	0
Exchange differences, right-of-use-assets	0	0
Depreciation, right-of-use assets	(5)	(6)
Right-of-use asset, ending balance	$ (25)	$ (6)

Leases - Right-of-Use Asset Dep

Leases - Right-of-Use Asset Depreciation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disclosure of quantitative information about right-of-use assets [line items]
Depreciation, right-of-use assets	$ 379	$ 286
R&D expense
Disclosure of quantitative information about right-of-use assets [line items]
Depreciation, right-of-use assets	324	227
G&A expense
Disclosure of quantitative information about right-of-use assets [line items]
Depreciation, right-of-use assets	$ 55	$ 59

Leases - Schedule of Lease Liab

Leases - Schedule of Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Disclosure Of Quantitative Information About Lease Liabilities [Line Items]
Beginning balance	$ 3,467	$ 5,031
Additions	5,401
Cash outflow (including interest)	(318)	(309)
Interest	18	31
Exchange difference	(136)	(66)
Ending balance	8,432	4,687
Lease liabilities, short-term	833	1,122	$ 1,002
Lease liabilities, long-term	7,599	3,565	$ 2,465
Properties (Offices)
Disclosure Of Quantitative Information About Lease Liabilities [Line Items]
Beginning balance	3,402	4,953
Additions	5,345
Cash outflow (including interest)	(313)	(304)
Interest	18	30
Exchange difference	(133)	(66)
Ending balance	8,319	4,613
Lease liabilities, short-term	799	1,103
Lease liabilities, long-term	7,520	3,510
Vehicles
Disclosure Of Quantitative Information About Lease Liabilities [Line Items]
Beginning balance	65	78
Additions	56
Cash outflow (including interest)	(5)	(5)
Interest	0	1
Exchange difference	(3)	0
Ending balance	113	74
Lease liabilities, short-term	34	19
Lease liabilities, long-term	$ 79	$ 55

Convertible loans - Narrative (

Convertible loans - Narrative (Details) $ in Thousands	Apr. 24, 2020USD ($)borrowingComponent	Mar. 31, 2021USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)	May 19, 2020USD ($)
Disclosure of detailed information about borrowings [line items]
Cash and cash equivalents, minimum quarterly balance		$ 50,000
Convertible loans, derivatives, change in fair value income		21,169	$ 0
Convertible loans, derivatives		52,039		$ 73,208
Convertible loans, short-term		$ 3,594		3,631
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%
Exit fee	2.00%
Cash and cash equivalents, minimum quarterly balance	$ 50,000
Implied effective interest rate		23.00%
Loans received		$ 39,367
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		15,268
Convertible loans, derivatives		35,961		51,229
Interest expense on borrowings		1,982
Loans received				38,406
Convertible loans, short-term		3,594		3,631
Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of detailed information about borrowings [line items]
Borrowings, maximum borrowing capacity	50,000
Borrowings	$ 50,000
Convertible loans, derivatives, change in fair value income		5,901
Convertible loans, derivatives		$ 16,078		$ 21,979
Increase (decrease) in estimated probability of derivative		10.00%
Value of change in derivative		$ 1,608

Convertible loans - Valuation o

Convertible loans - Valuation of Derivative (Details)	May 19, 2020$ / shares	Apr. 24, 2020	Mar. 31, 2021$ / sharesperiod	Dec. 31, 2020$ / sharesperiod
Disclosure of detailed information about borrowings [line items]
Floor of IPO price		81.00%
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%
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) | 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) | 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) | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			24.41	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			24.41	32.01
Risk-free interest rate | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0.007	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			0.007	0.003
Expected volatility | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0.90	0.90
Expected volatility | 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 | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations | period			49	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			2	5
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 | 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 | Derivatives | Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations			0.125	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			0.079	0.074

Convertible loans - Schedule of

Convertible loans - Schedule of the First Tranche (Details) - USD ($) $ in Millions	May 19, 2020	Apr. 24, 2020
Disbursement upon completion of IPO
Disclosure of detailed information about borrowings [line items]
Borrowings	$ 65	$ 65

Share-based compensation - Narr

Share-based compensation - Narrative (Details) $ / shares in Units, $ in Thousands	Mar. 22, 2021shares	Mar. 31, 2021USD ($)shares$ / shares	Mar. 31, 2020USD ($)	Dec. 31, 2020shares	Nov. 30, 2019shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized		$ 13,951
Share-based compensation expense		$ 13,951	$ 3,790
Contractual term		10 years
Number of share options outstanding in share-based payment arrangement (in shares) | shares		6,190,974		4,276,973
Share Options
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized		$ 12,692	2,616
Vesting period		3 years
Contractual term		10 years
Number of instruments granted in share-based payment arrangement | shares	1,592,651	1,592,651
Weighted-average grant-date fair value (in dollars per share) | $ / shares		$ 20.53
Awards vested and exercisable (in shares) | shares		679,874
Weighted average strike price, vested and exercisable (in dollars per share) | $ / shares		$ 18.75
Weighted average remaining life, vested and exercisable		8 years 10 months 28 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) | shares		0
Number of instruments granted in share-based payment arrangement | shares	377,255
Share Purchase Plan 2016
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized		$ 0	992
Incentive Plan 2014
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized		$ 0	182
Strike price (in USD per share) | $ / shares		$ 19
Vesting period		4 years
2019 Equity Incentive Plan
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized		$ 2,616
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 | shares		1,063,893			7,820,000
Share-based compensation expense		$ 49,449
2019 Equity Incentive Plan | Restricted Stock Units
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized		$ 1,259	$ 0

Share-based compensation - Sche

Share-based compensation - Schedule of Number of Awards Outstanding and Weighted Average Strike Price (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2021shares$ / shares	Dec. 31, 2020shares$ / 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
Fair value grant date (in USD per share) | $ / shares	28.92
Average strike price in USD per share, Forfeited (in USD per share) | $ / shares	21.73
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	$ 27.27	$ 26.45
Number of awards, At beginning of the year (in shares) | shares	4,276,973
Number of awards, Granted (in shares) | shares	1,958,246
Number of awards, Forfeited (in shares) | shares	(44,090)
Number of awards, Exercised (in shares) | shares	(155)
Number of awards, At end of the year (in shares) | shares	6,190,974	4,276,973
Weighted average remaining contractual life of outstanding share options	9 years 4 months 6 days	9 years 3 months 14 days
Weighted average remaining contractual life of granted share options	9 years 11 months 4 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
	Mar. 31, 2021USD ($)shares$ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expected volatility	85.00%
Expected dividends | $	$ 0
Minimum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average share price (in USD per share)	$ 27.32
Strike price (in USD per share)	$ 27.32
Award life | shares	5.50
Risk-free interest rate	51.00%
Maximum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average share price (in USD per share)	$ 32.22
Strike price (in USD per share)	$ 32.22
Award life | shares	6.08
Risk-free interest rate	1.12%

Share-based compensation - Sc_2

Share-based compensation - Schedule of Other Equity Instruments Outstanding (Details) - Restricted Share Units (RSU)	3 Months Ended
	Mar. 31, 2021shares$ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of awards, beginning of period (in shares) | shares	149,984
Number of awards, granted (in shares) | shares	412,099
Number of awards, end of period (in shares) | shares	562,083
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
	Mar. 31, 2021	Mar. 31, 2020
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized	$ 13,951	$ 3,790
Incentive Plan 2014
Disclosure of terms and conditions of share-based payment arrangement [line items]
Increase in reserve of share-based payments	0	182
Share Purchase Plan 2016
Disclosure of terms and conditions of share-based payment arrangement [line items]
Increase in reserve of share-based payments	0	992
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	12,692	2,616
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	$ 1,259	$ 0

Related parties - Narrative (De

Related parties - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)subsidiary	Mar. 31, 2020USD ($)
Disclosure of transactions between related parties [line items]
Services provided to, related party transactions | $	$ 1	$ 1
Auven Therapeutics Holdings, L.P.
Disclosure of transactions between related parties [line items]
Number of subsidiaries provide services to | subsidiary	3

Related parties - Schedule of K

Related parties - Schedule of Key Management Compensation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Related Party [Abstract]
Salaries and other short-term employee costs	$ 2,032	$ 1,605
Pension costs	134	149
Share-based compensation expense	5,217	1,581
Other compensation	13	62
Key management compensation	$ 7,396	$ 3,397

Loss per share (Details)

Loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings per share [abstract]
Net loss	$ (51,527)	$ (43,476)
Weighted average number of ordinary shares outstanding	76,721,667	50,959,156
Net loss per share, basic and diluted (in USD per share)	$ (0.67)	$ (0.85)

Loss per share -Schedule of Pot

Loss per share -Schedule of Potentially Dilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings per share [line items]
Potentially dilutive securities	7,510,484	6,548,110
Incentive Plan 2014
Earnings per share [line items]
Potentially dilutive securities	0	2,183,856
Share Purchase Plan 2016
Earnings per share [line items]
Potentially dilutive securities	0	3,346,960
2019 - Share Options
Earnings per share [line items]
Potentially dilutive securities	4,683,132	1,017,294
Equity Incentive Plan 2019 - RSUs
Earnings per share [line items]
Potentially dilutive securities	195,773	0
Conversion of the principal amount of convertible loans into the Company’s common shares
Earnings per share [line items]
Potentially dilutive securities	2,631,579	0

Events after the reporting da_2

Events after the reporting date (Details) - USD ($) $ in Millions	Apr. 23, 2021	Apr. 24, 2020
Disbursement upon receipt of regulatory approval for ZYNLONTA
Disclosure of non-adjusting events after reporting period [line items]
Borrowings, maximum borrowing capacity		$ 50
Regulatory Approval Of Commercial Grade Drug Product | Minimum
Disclosure of non-adjusting events after reporting period [line items]
Reversal of previously recorded impairment charge	$ (7)
Regulatory Approval Of Commercial Grade Drug Product | Maximum
Disclosure of non-adjusting events after reporting period [line items]
Reversal of previously recorded impairment charge	$ (8)