| Summary of Significant Accounting Policies | Summary of Significant Accounting Policies Basis of preparation and principles of consolidation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) and include the accounts of the Company and its wholly-owned subsidiaries. Intercompany transactions and balances have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosures in the consolidated financial statements and accompanying notes. Management bases its estimates on historical experience and on assumptions believed to be reasonable under the circumstances. Actual results could differ materially from those estimates. Going Concern We are responsible for evaluating, and providing disclosure of uncertainties about, our ability to continue as a going concern. As of December 31, 2023, we had cash and cash equivalents of $278.6 million. Based on our evaluation, we concluded there is no substantial doubt about our ability to continue as a going concern within one year from the date the Consolidated Financial Statements were issued. Risks and Uncertainties The Company is subject to risks and uncertainties common to companies in the global biotechnology and pharmaceutical industries, including, but not limited to, risks of failure or unsatisfactory results of its research and development efforts and clinical studies, the need for significant capital to fund the continued development of its products and pipeline, the need to obtain and maintain marketing approval for its product and candidates, the need to successfully commercialize and gain market acceptance of any of its product candidates that obtain regulatory approval, dependence on strategic relationships with collaboration and commercialization partners and on key personnel, securing and protecting proprietary technology, compliance with government regulations, competition, and dependence on third-party service providers such as contract research organizations (“CROs”), contract manufacturing organizations (“CMOs”), other suppliers, and third-party logistics providers. Concentrations of Risk Foreign exchange risk The Company operates internationally and is exposed to foreign exchange risk arising from various currency exposures, primarily with respect to British pounds, Euros and Swiss francs. Transaction exposure arises because the amount of local currency paid or received in transactions denominated in foreign currencies may vary due to changes in exchange rates. Foreign exchange risk arises from: – forecast costs denominated in a currency other than the entity’s functional currency; – recognized assets and liabilities denominated in a currency other than the entity's functional currency; and – net investments in foreign operations. Management believes that foreign exchange risk is minimal, as the Company pays invoices mainly in U.S. dollars and holds cash principally in U.S. dollars. Interest rate risk Interest rate risk arises from movements in interest rates which could have adverse effects on the Company's net loss or financial position. Changes in interest rates cause variations in interest income and expenses on interest-bearing assets and liabilities, and on the value of the net defined benefit pension obligation. In relation to the royalty purchase agreement with HCR, the Company is obligated to pay interest in the form of royalties in connection with certain net sales and licensing revenue. As the effective interest rate (“EIR”) on the deferred royalty obligation does not depend on market performance, the exposure to interest rate and market risk is deemed low. See note 13, “Deferred royalty obligations” for further information. In regards to the senior secured term loans, the interest rate is variable and dependent upon market factors. The Company will update the EIR at the end of each reporting period for changes in the rate. See note 10, "Senior secured term loan facility and warrants" for further information. Credit risk Credit risk is the risk that a counterparty will not meet its obligations under a financial instrument or customer contract, leading to a financial loss. The Company is exposed to credit risk from its operating activities and from its financing activities including deposits with banks and other financial institutions. The Company’s cash and cash equivalents accounts are maintained with well established, highly rated financial institutions. The Company’s wholly-owned subsidiaries are solvent, are managed on a cost-plus service provider basis, and are supported by the Company as the parent. To date, the Company’s only source of product revenue, which commenced during May 2021, has been sales of ZYNLONTA only in the U.S., which is sold primarily through wholesale distributors. In addition, the Company earns license revenues and royalties through its license agreements with third parties. See note 17 “Revenue” for further information. We continuously monitor the creditworthiness of our customers and have internal policies regarding customer credit limits. When determining customer allowances for estimated credit losses, the Company analyzes accounts that are past due, the creditworthiness of its customers, current economic conditions and, when sufficient historical data becomes available, actual credit losses incurred by the Company. As of December 31, 2023, and 2022, the Company did not record an allowance for expected credit losses as it was considered immaterial. Liquidity risk Liquidity risk is the risk that the Company may not be able to generate sufficient cash resources to settle its obligations in full as they fall due or can do so only on terms that are materially disadvantageous. Prudent liquidity risk management implies maintaining sufficient cash to cover working capital requirements. Cash is monitored by the Company’s management. Funding and liquidity risks are reviewed regularly by management and the Board of Directors. The Board of Directors reviews the Company’s ongoing liquidity risks quarterly as part of the financial review process and on an ad hoc basis as necessary. To date, the Company has funded its capital requirements through capital raises, including the issuance of the Company’s common shares, the issuance of convertible loans, the issuance of term loans, partnering of its programs and royalty financings. The Company may need to raise additional capital in the future, and that such financing may not be available on acceptable terms, or at all. Other Concentrations of Risk We depend on single source suppliers for certain components of our inventory, and our production, warehousing and distribution operations are outsourced to third-party suppliers and CMOs where a significant portion of our inventory is located. Disruption of supply from key vendors or third-party suppliers may have a material adverse impact on our operations and financial results. Our primary source of revenue is from sales of ZYNLONTA. Historically, we have not experienced significant credit losses on our accounts receivable and as of December 31, 2023 and 2022, allowances on receivables were not material. Four customers accounted for 96% and 100% of gross accounts receivable as of December 31, 2023, and 2022, respectively. Foreign currency translation Functional and presentation currency Items included in the financial statements of each of the Company’s entities are measured using the currency of the primary economic environment in which the entity operates (“the functional currency”). The consolidated financial statements are presented in US dollars (“$” or “USD”), which is the Company’s functional and Group’s reporting currency. Transactions and balances Foreign currency transactions are translated into the functional currency using the exchange rates prevailing at the dates of the transactions. Foreign exchange gains and losses resulting from the settlement of such transactions and from the translation at year-end exchange rates of monetary assets and liabilities denominated in foreign currencies are recognized in consolidated statement of operation. All foreign exchange gains and losses are presented in the consolidated statement of operation within “Other, net.” Wholly-owned subsidiaries The results and financial position of all the Company’s entities that have a functional currency different from the reporting currency are translated into the reporting currency as follows: (i) assets and liabilities for each balance sheet presented are translated at the closing rate at the date of that balance sheet; (ii) income and expenses for each consolidated statement of operation are translated at monthly average exchange rates; and (iii) all resulting exchange differences are recognized in other comprehensive loss, under “Cumulative translation adjustments.” Monetary assets and liabilities are translated at exchange rates in effect at the balance sheet date while non-monetary assets and liabilities are translated at historical exchange rates. Exchange gains and losses resulting from remeasurement adjustments are recorded within general and administration costs in the consolidated statements of operation. Foreign currency exchange rates The following exchange rates have been used for the translation of the financial statements of ADCT UK, the functional currency of which is the British pound: Year ended December 31, 2023 2022 US $ / GBP Closing rate, GBP 1 1.2731 1.2097 Weighted average exchange rate, GBP 1 1.2431 1.1847 Cash and cash equivalents Cash and cash equivalents include demand deposits held at financial institutions and other short-term highly liquid investments with original maturities of three months or less that are readily convertible to cash. Fair value measurements Financial assets and liabilities are required to be measured and reported at fair value at each reporting period. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability, an exit price, in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value includes: 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. Accounts receivable Trade accounts receivable represent amounts due from customers from product sales and are stated net of customer sales allowances for chargebacks, product returns and estimated credit losses. The Company’s payment terms range from 30 to 90 days. When determining customer allowances for estimated credit losses, the Company analyzes accounts that are past due, the creditworthiness of its customers, current economic conditions and, when sufficient historical data becomes available, actual credit losses incurred by the Company. As of December 31, 2023, and 2022, the Company did not record an allowance for expected credit losses as it was considered immaterial. License revenue and royalties receivable, as well as other amounts due from the Company’s partners, are included in accounts receivable and are typically payable to us within 45 to 60 days after the end of each quarter in which they were earned. As of December 31, 2022, accounts receivable included $50 million in license fees from Swedish Orphan Biovitrum AB (publ) (“Sobi”) for the approval of the Marketing Authorisation Application by the European Commission for ZYNLONTA in third-line DLBCL. Inventory Inventory is stated at the lower of cost or net realizable value with costs determined on a first-in, first-out basis. Reserves for potentially excess, dated or obsolete inventories are established as a write-down to inventory and a charge to cost of product sales based on forecasted product demand estimates and the likelihood of consumption in the normal course of business, considering the expiration dates of the inventories on hand, planned production volumes and required production lead times. Property and equipment All property and equipment is stated at historical cost less accumulated depreciation. Historical cost includes expenditure that is directly attributable to the acquisition of the items. Depreciation is calculated using the straight-line method to reduce the cost of each asset to its residual value over its estimated useful life, as follows: Leasehold improvements 3 to 10 years Laboratory equipment 5 years Office equipment 5 years Hardware and computer software 3 years Leases The Company recognizes operating lease right-of-use (“ROU”) assets and operating lease liabilities when the Company obtains the right to control the asset under a leasing arrangement with an initial term greater than twelve months. The Company evaluates the nature of each lease at the inception of an arrangement to determine whether it is an operating or financing lease and recognizes the operating lease ROU asset and operating lease liability based on the present value of future minimum lease payments over the expected lease term. The lease payments are discounted using the interest rate implicit in the lease. If that rate cannot be determined, the Company uses the incremental borrowing rate we would expect to pay to borrow on a similar collateralized basis over a similar term in order to determine the present value of our lease payments. Operating lease ROU assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Certain lease arrangements contain renewal or termination options that have been included in the determination of the lease term if the options are reasonably certain of being exercised. For contracts that contain lease and non-lease components, the Company accounts for both components as a single lease component. Lease expense for operating leases is recognized on a straight-line basis over the lease term. Investments in joint venture The Company has an investment in a joint venture in which we own less than 50% and do not control the investee. The investment is accounted for using the equity method given our ability to exercise significant influence over the operating and financial decisions of the investee. The Company recognized its share of the investee’s profit or losses, other comprehensive income or losses and capital transactions as an adjustment to the carrying value of its investment in joint venture. 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, 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 Company’s Investment in joint venture is assessed for impairment when events or circumstances indicate the carrying value of the investment may be impaired based on qualitative factors. Impairment of long-lived assets The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. If such circumstances are determined to exist, an estimate of undiscounted future cash flows produced by the long-lived asset, including its eventual residual value, is compared to the carrying value to determine whether impairment exists. In the event that such cash flows are not expected to be sufficient to recover the carrying amount of the assets, the assets are written-down to their estimated fair values. For the years ended December 31, 2023 and 2022, there were no material impairments of the value of long-lived assets. Loans Loans are initially recognized at fair value, net of transaction costs incurred. Loans are subsequently measured at amortized cost using an effective interest rate (“EIR”). Loans are presented as a financial liability in the consolidated balance sheet. Debt is classified as a current liability when due within 12 months after the end of the reporting period. The remainder of the amount is presented as a long-term liability. The Company recognizes debt extinguishment in Other income (expense) as the difference between the extinguishment payment and the carrying value of the loan. Warrants The Company accounts for warrants as either equity-classified or liability-classified instruments based on an assessment of the warrant’s specific terms and applicable authoritative guidance included in Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 480, Distinguishing Liabilities from Equity (“ASC 480”), ASC 815, Derivatives and Hedging (“ASC 815”) and Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”). The assessment considers whether the warrants are freestanding financial instruments pursuant to ASC 480, whether the warrants meet the definition of a liability pursuant to ASC 480, and whether the warrants meet all of the requirements for equity classification under ASC 815, including whether the warrants are indexed to the Company’s own common stock and whether the warrant holders could potentially require “net cash settlement” in a circumstance outside of the Company’s control, among other conditions for equity classification. This assessment, which requires the use of professional judgment, is conducted at the time of warrant issuance and as of each subsequent quarterly period end date while the warrants are outstanding. For warrants that are classified as liabilities, the Company records the fair value of the warrants at each balance sheet date and records changes in the estimated fair value as a gain or loss in Other, net. Derivative Liability The Company analyzes the conversion feature of convertible notes for derivative accounting consideration under ASC 815-15 and ASU 2020-06, which requires that the conversion features are bifurcated and separately accounted for as a derivative instrument on the balance sheet at fair value. Any unrealized change in fair value, as determined at each measurement period, is recorded in Other, net and the associated carrying amount on the balance sheet is adjusted by the change. Upon extinguishment of a convertible note where the embedded conversion option has been bifurcated and accounted for as a derivative liability, the Company records the shares at fair value, relieves all related notes, derivatives and debt discounts and recognizes a net gain or loss on debt extinguishment. Employee benefits Employee Pension Plans The Company’s wholly-owned subsidiaries operate defined benefit and defined contribution pension plans in accordance with the local conditions and practices in the countries in which they operate. Certain employees of the UK subsidiary are covered by local defined contribution plans. The defined benefit schemes are generally funded through payments to insurance companies or trustee-administered funds, determined by periodic actuarial calculations. A defined contribution plan is a plan that provides an individual account for each participant and provides benefits that are based on all of the following: amounts contributed to the participant’s account by the employer or employee; investment experience; and any forfeitures allocated to the account, less any administrative expenses charged to the plan. A defined benefit plan is a pension plan that is not a defined contribution plan. Typically, defined benefit plans define an amount of pension benefit that an employee will receive on retirement, usually dependent on one or more factors such as age, years of service and compensation. However, as is the case with many Swiss pension plans, although the amount of ultimate pension benefit is not defined, certain legal obligations of the plan nevertheless create constructive obligations on the employer to pay further contributions to fund an eventual deficit. This results in the plan being accounted for as a defined benefit plan. The liability recognized in the balance sheet in respect of defined benefit pension plans is the present value of the defined benefit obligation at the end of the reporting period less the fair value of plan assets. The defined benefit obligation is calculated annually by a third party using the projected unit credit method. The present value of the defined benefit obligation is determined by discounting the estimated future cash outflows using interest rates of high-quality corporate bonds that are denominated in the currency in which the benefits will be paid, and that have terms to maturity that approximate the terms of the related pension obligation. The current service cost of the defined benefit plan is recognized in the consolidated statement of operation in employee benefit expenses, except where included in the cost of an asset, reflects the increase in the defined benefit obligation resulting from employee service in the current year. Past service costs, resulting from a plan amendment or curtailment, are recognized in Other comprehensive (loss) income and amortized to the statements of operations and comprehensive loss over the average remaining service period of active employees. The net interest cost is calculated by applying the discount rate to the net balance of the present value of the defined benefit obligation and the fair value of plan assets. This cost is included in employee benefit expenses in the consolidated statement of operation. Actuarial gains and losses arising from experience adjustments and changes in actuarial assumptions are recognized in Other comprehensive (loss) income in the period in which they arise and amortized to the statements of operations and comprehensive loss in subsequent periods using the corridor approach. For defined contribution plans, the company pays contributions to publicly or privately administered pension insurance plans on a mandatory, contractual or voluntary basis. Once the contributions have been paid, the company has no further payment obligations. The contributions are recognized as employee benefit expenses in the consolidated statement of operation. Prepaid contributions are recognized as an asset to the extent that a cash refund or a reduction in the future payments is available. Share-based Compensation The Company grants share-based awards. The fair value of awards expected to vest are recognized as an employee share-based compensation expense using the graded accelerated vesting method over the requisite service period of the award less actual forfeitures. The fair value of each stock option is estimated on the date of grant using the Black-Scholes option valuation model, that requires the use of assumptions including the expected volatility of the Company’s stock price, expected term, risk-free rate and the fair value of the underlying common stock. We estimate the fair value of restricted stock units granted based on the closing market price of our common stock on the date of grant. Actual forfeitures are recognized as they occur. Employee Stock Purchase Plan The fair value of purchase rights granted under the employee stock purchase plan is recognized as an employee share-based compensation expense with a corresponding increase in Additional paid-in capital. The total amount to be expensed is determined by reference to the fair value of the purchase rights granted. The total expense is recognized over the offering period, which is the period over which all of the specified vesting conditions are to be satisfied. Participants that voluntarily withdraw from the plan are accounted for as a cancellation and total share-based compensation recorded in the period in which the participant withdraws. Terminations are accounted for as forfeitures and any share-based compensation expense reversed in the period the participant terminates. Accumulated payroll deductions are recorded within Accrued expenses in other current liabilities until the shares are purchased by the participant at the end of the offering period. Revenue Recognition The Company recognizes revenue when or as control of promised goods or services is transferred to its customers in an amount that reflects the consideration to which the Company expects to receive in exchange for those goods or services. The Company follows a five-step model: (i) identify the customer contract; (ii) identify the contract’s performance obligation; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations; and (v) recognize revenue when, or as, a performance obligation is satisfied. Product revenue The Company generates revenue from sales of ZYNLONTA in the U.S. for the treatment of relapsed or refractory DLBCL, which was approved by the FDA on April 23, 2021 and launched shortly thereafter. Revenue is recognized when control is transferred to the customer at the net selling price, which includes reductions for gross-to-net (“GTN”) sales adjustments such as 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. Management also uses information from external sources to identify prescription trends, patient demand, average selling prices, discarded volumes and sales return and allowance data for the Company and 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. In particular, the following rebate requires a substantial degree of judgement. Discarded Drug Rebate The Infrastructure Investment and Jobs Act requires manufacturers of certain single-source drugs separately paid for under Medicare Part B and marketed in single-dose containers or packages to provide annual refunds (“discarded drug rebate”), if those portions of the dispensed drug that are unused and discarded exceed an applicable percentage defined by statute or regulation. The Centers for Medicare & Medicaid Services (the “CMS”) finalized regulations to implement this section on November 18, 2022, and the provision went into effect on January 1, 2023. In particular, the estimate for the discarded drug rebate requires a substantial degree of judgement. The Company began estimating and recording a provision for the discarded drug rebate as a GTN sales adjustment beginning in the first quarter of 2023, which is included in Other long-term liabilities due to the long-term nature of when the first annual refunds are expected to come due. The significant assumptions used to estimate the discarded drug rebate include legal interpretations of applicable laws and regulations, historical experience with discarded volumes and time lags in the processing of claims and invoicing from CMS. Management uses a number of factors to estimate the discarded drug rebate, including information from external sources to identify the Company’s discarded volumes, preliminary information from CMS on estimated discarded volumes, as well as legal interpretations of the payment limit amount and J-code billing unit used in the discarded drug rebate calculation. License arrangements The Company recognizes revenues from license fees for intellectual property (IP) either at a point in time or over time. The Company must make an assessment as to whether such a license represents a right-to-use the IP (at a point in time) or a right to access the IP (over time). The Company recognizes revenue for a right-to-use license immediately if the licensee can begin to use and benefit from the IP upon commencement of the license term and the Company has no further obligations in the context of the IP. A license is considered a right to access the IP when the Company undertakes activities during the license term that may significantly affect the IP, which directly exposes the customer to any positive or negative effects arising from such activities. These activities do not result in the immediate transfer of a good or service to the customer. As such, revenues from the right to access the IP are recognized over time. The Company may enter into agreements with multiple performance obligations. Performance obligations are identified and separated when the other party can benefit from the license on its own or together with other resources that are readily available, and the license is separately identifiable from other goods or services in the contract. Transaction prices for out-license arrangements may include fixed up-front amounts as well as variable consideration such as contingent development and regulatory milestones, sales-based milestones and royalties. The most likely amount method is used to estimate contingent development and regulatory milestones because the ultimate outcomes are binary in nature. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue will not occur when the uncertainty associated with the variable consideration is subsequently resolved. To the extent arrangements include multiple performance obligations that are distinct, the transaction price assigned to each distinct performance obligation is reflective of the relative stand-alone selling price when sold separately or estimated stand-alone selling price on the basis of comparable transactions with other customers when such goods or services are not sold separately. The residual approach is the method used to estimate a stand-alone selling price when the selling price for a good or service is highly variable or uncertain. In determining the transaction prices, sales milestones and royalties attributable to licenses are excluded from the variable consideration guidance and recognized at the later of when the subsequent sales transaction occurs, or the satisfaction or partial satisfaction of the performance obligation to which some or all of the royalty has been allocated. Cost of product sales Cost of product sales primarily includes direct and indirect costs relating to the manufacture of ZYNLONTA from third-party providers of manufacturing, distribution and logistics, and royalties to a collaboration partner based on net product sales of ZYNLONTA. Inventory amounts written down as a result of excess or obsolescence are charged to Cost of product sales. Research and Development (“R&D”) expenses R&D costs are expensed as incurred, and consist of salaries and benefits of employees, share-based compensation costs, fees paid to clinical research organizations (“CROs”) and contract manufacturing organizations (“CMOs”), upfront fees and achieved milestone payments associated with R&D collaboration arrangements, supplies, facilities costs and allocated overhead expenditures. Clinical study and certain research costs are recognized over the service periods specified in the contracts and adjusted as necessary based upon an ongoing review of the level of effort and costs actually incurred. The Company is required to estimate its expenses resulting from its obligation under cont |
