Unaudited IFRS Condensed Consolidated Interim Financial Statements as of and for the three and nine months ended September 30, 2023.

1.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 three wholly-owned subsidiaries: ADC Therapeutics America, Inc. (“ADCT America”), which was incorporated in Delaware, USA on December 10, 2014, ADC Therapeutics (UK) Ltd (“ADCT UK”), which was incorporated in England on December 12, 2014 and ADC Therapeutics (NL) B.V. which was incorporated in the Netherlands on February 25, 2022. The Company and its three subsidiaries form the ADCT Group (the “Group”).

The Group is focused on the development and commercialization of antibody drug conjugates (“ADCs”), including research, development, human clinical trials, regulatory approval and commercialization. On April 23, 2021, the U.S. Food and Drug Administration (“FDA”) approved ZYNLONTA for the treatment of relapsed or refractory diffuse large B-cell lymphoma (“DLBCL”) and the Company commenced recognizing revenue upon the sale of ZYNLONTA during the second quarter of 2021. ADCs are drug constructs which combine monoclonal antibodies specific to particular types of cells with cytotoxic molecules or warheads which seek to kill cancer cells to which the ADC attaches. ADCs have extensive potential therapeutic applications in cancer.

These unaudited condensed consolidated interim financial statements were authorized for issue on November 7, 2023.

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, license agreements, the issuance of the Company’s common shares, the issuance of convertible loans, the issuance of term loans and proceeds from a royalty purchase agreement. 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 senior secured term loan facility, it must maintain a balance of at least USD 60.0 million in cash and cash equivalents plus any accounts payable that are greater than ninety days old at the end of each quarter.

As of September 30, 2023, the Group’s cash and cash equivalents amounted to USD 310.4 million (December 31, 2022: USD 326.4 million).

Management believes that the Group has sufficient resources to meet its financial obligations 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.

2.Basis of preparation

These unaudited condensed consolidated interim financial statements as of and for the three and nine months ended September 30, 2023 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, 2022.

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:

The unaudited condensed consolidated interim financial statements incorporate the financial statements of the Company and entities controlled by the Company which are the same as those contained in the audited consolidated financial statements as of and for the year ended December 31, 2022.

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, 2022. There have been no material changes to the use of estimates and judgements other than those described in note 3, "Significant accounting policies."

3.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, 2022 and have been applied consistently to all periods presented in these unaudited condensed consolidated interim financial statements, except for the following:

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.

On November 15, 2021, the Infrastructure Investment and Jobs Act was enacted, which added a requirement for manufacturers of certain single-source drugs (including biologics and biosimilars) separately paid for under Medicare Part B for at least 18 months and marketed in single-dose containers or packages (known as refundable single-dose container or single-use package drugs) to provide annual refunds 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.

The Company has accounted for this annual refund (“discarded drug rebate”) as a GTN sales adjustment beginning in the first quarter of 2023. The discarded drug rebate will involve significant estimates and judgment after considering factors including legal interpretations of applicable laws and regulations, historical experience with discarded volumes and processing time lags.

The Company uses information from external sources to identify the Company’s discarded volumes and estimate the discarded drug rebate. The Company’s estimates are subject to inherent limitations of estimates that rely on third-party information 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 for the discarded drug rebate are being assessed each period and adjusted as required to revise information or actual experience.

There are no new IFRS standards, amendments to standards or interpretations that are mandatory for the financial year beginning on January 1, 2023, that are relevant to the Group. 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.

4.Financial risk management 

4.1Financial 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, 2022. In relation to the royalty purchase agreement with entities managed by Healthcare Royalty Management, LLC ("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 17, “Deferred royalty obligation” 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 13, "Senior secured term loan facility and warrants" for further information. A hypothetical 100 basis point increase (decrease) in the interest rate as of September 30, 2023 would have increased (decreased) the effective interest expense associated with the Company's senior secured term loan facility by KUSD 1,124 and (KUSD 1,124). There have been no other material changes in financial risk management since December 31, 2022.

4.2Fair value estimation

As of September 30, 2023, the carrying amount is a reasonable approximation of fair value for the following financial assets and liabilities:

•Cash and cash equivalents

•Trade accounts receivable; and

•Trade accounts payable

In the nine months ended September 30, 2023, there were no significant changes in the business or economic circumstances that affected the fair value of the Group’s financial assets and financial liabilities.

Fair values must be estimated at the end of each reporting period with regard to the senior secured term loan warrant obligation and the Deerfield warrants. The approach to valuation follows the grant date fair value principle, and the key input factors are described for the senior secured term loan facility warrant obligation in note 13, "Senior secured term loan facility and warrants" and for the Deerfield warrants in note 15, "Deerfield warrants." Commonly accepted pricing models (Black-Scholes) have been used to calculate the fair values. The valuation of the senior secured term loan facility warrant obligation and Deerfield warrants are classified as pertaining to Level 2 of the valuation hierarchy. The convertible loan derivatives previously were classified as pertaining to Level 3 of the valuation hierarchy and were extinguished on August 15, 2022. See note 14, "Convertible loans" for further information. The Company no longer has any inputs 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.

5.Revenue recognition

The table below provides a disaggregation of revenues by type of service and customer location for the three and nine months ended September 30, 2023 and September 30, 2022.

(1) Europe, the Middle East and Africa

Product revenues, net from sales of ZYNLONTA were KUSD 14,267 and KUSD 52,417 for the three and nine months ended September 30, 2023. Product revenues, net from the sales of ZYNLONTA were KUSD 21,321 and KUSD 55,110 for the three and nine months ended September 30, 2022, respectively. The Company records its best estimate of GTN sales adjustments to which customers are likely to be entitled.

The table below provides a rollforward of the Company’s accruals related to the GTN sales adjustments for the three and nine months ended September 30, 2023 and September 30, 2022.