ADC Therapeutics SA

Table of Contents

ADC Therapeutics SA

NOTES TO THE CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

(Unaudited)

(in thousands, except share and per share amounts)

1. Description of Business and Organization

ADC Therapeutics is a commercial-stage global pioneer in the field of antibody drug conjugates (“ADCs”), transforming treatment for patients through our focused portfolio with ZYNLONTA® (loncastuximab tesirine-lpyl), a CD19-directed ADC.

The Company generates sales from its flagship product, ZYNLONTA which received accelerated approval from the U.S. Food and Drug Administration (“FDA”), conditional approval from the European Commission, the China National Medical Products Administration (“NMPA”) and Health Canada, as well as approvals in other key global markets for the treatment of relapsed or refractory diffuse large B-cell lymphoma (“DLBCL”) after two or more lines of systemic therapy. Additionally, the Company is pursuing expansion into earlier lines of therapies and indolent lymphomas through Company sponsored trials and investigator initiated studies.

The Company was incorporated on June 6, 2011 under the laws of Switzerland, with its registered office located at Route de la Corniche 3B, 1066 Epalinges, Switzerland. The Company hastwo 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”), incorporated in England on December 12, 2014. The Company and itstwo subsidiaries form the ADCT Group (the “Group”).

All references to “ADC Therapeutics,” “ADCT,” “the Company," “we,” “us,” and “our” refer to ADC Therapeutics SA and its consolidated subsidiaries unless otherwise indicated.

2. Summary of Significant Accounting Policies

Basis of preparation and principles of consolidation

These accompanying unaudited condensed consolidated financial statements, which include the accounts of the Company and its wholly-owned subsidiaries, have been prepared following the requirements of the U.S. Securities and Exchange Commission for interim reporting. As permitted under those rules, certain footnotes and other financial information that are normally required by U.S. generally accepted accounting principles, or U.S. GAAP, can be condensed or omitted. All intercompany transactions and balances have been eliminated in consolidation. The information included in this Quarterly Report on Form 10‑Q should be read in conjunction with our annual audited consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10‑K for the year ended December 31, 2025.

In the opinion of management, these condensed consolidated financial statements have been prepared on the same basis as the annual audited consolidated financial statements and include all adjustments, consisting only of normal recurring adjustments, considered necessary for the fair statement of our financial position and operating results. The results for the three and nine months ended September 30, 2026 are not necessarily indicative of the results to be expected for the year ending December 31, 2026, for any other interim period or for any future period.

The Company’s significant accounting policies have not changed substantially from those previously described in the Company’s Annual Report on Form 10‑K for the year ended December 31, 2025.

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.

Loan Modifications and Extinguishments

On February 18, 2026, the Company entered into an amendment to its royalty purchase agreement with certain entities managed by HealthCare Royalty Management, LLC ("HCR"). Prior to the amendment, the agreement was accounted for as a debt obligation. The Company evaluates amendments, restructurings, or other changes to its loan agreements in accordance with ASC 470-50, Debt — Modifications and Extinguishments. Under this guidance, we determine whether the revised terms represent a modification of the existing debt or an extinguishment of the old debt and issuance of new debt. If the changes are not deemed substantial, the transaction is accounted for as a modification and any associated fees or costs with the lender are amortized over the remaining term of the modified debt. If the changes are deemed to be substantial, the original debt is considered extinguished, and the new debt is recorded at fair value and any resulting difference between the carrying amount of the old debt and the fair value of the new debt is recognized in earnings as a gain or loss on extinguishment. When the Company repays an existing debt obligation using the proceeds from a contemporaneous issuance of new debt to a different lender, we account for the transaction as a debt extinguishment. See Note 7 for additional information regarding the HCR amendment and related accounting treatment.

Cost of product sales

Cost of product sales includes costs directly and indirectly relating to the manufacture of ZYNLONTA commercial drug substance and drug product, including the third-party manufacture costs of our contract manufacturing organizations (“CMOs”), as well as internal personnel costs, including share-based compensation, associated with the production of ZYNLONTA. Cost of product sales also includes royalties payable to a collaboration partner based on net product sales of ZYNLONTA, idle capacity costs, and inventory write-downs for changes in reserves for excess inventory or write-offs of inventory that fail to meet specification. We expect that cost of product sales will continue to increase over time as we sell through pre-approval inventory that was previously expensed prior to commercialization under U.S. GAAP. Factors such as inflation, tariffs and other external factors may also increase our cost of product sales.

Recent Accounting Pronouncements

New accounting pronouncements which have been adopted

We adopted FASB ASU-2025-05, Financial Instruments — Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets to simplify the estimation of credit losses on current accounts receivable and current contract assets arising from transactions accounted for under ASC 606, effective for fiscal years beginning in January 2026, including interim periods within those fiscal years. The ASU provides a practical expedient permitting an entity to assume that conditions at the balance sheet date remain unchanged over the life of the asset when estimating expected credit losses for current classified accounts receivable and contract assets. We adopted the practical expedient on a prospective basis for the quarterly and annual reports for the fiscal year beginning on January 1, 2026. Adoption of this standard did not have a material impact on our financial statements or disclosures.

Issued but not yet adopted

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses Disclosure. The ASU requires disaggregation, in the notes to the financial statements, of certain cost and expense captions presented on the face of the Company’s interim and annual financial statements. ASU 2024-03 is effective for fiscal years beginning in January 2027 and interim periods beginning January 2028, with early adoption permitted. Adoption may be applied prospectively or retrospectively. The Company does not anticipate that the adoption of this standard will have a material impact on our financial statements but may result in enhanced or expanded disclosures.

In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements. The ASU clarifies interim disclosure requirements, the applicability of ASC 270 and the form and content of interim financial statements in accordance with U.S. GAAP. The objective of the amendments is to provide further clarity about the current interim disclosure requirements. The ASU is effective for interim reporting periods within fiscal years beginning in January 2028. Adoption of this ASU may be applied prospectively or retrospectively. The Company is currently evaluating the impact of the ASU, but does not anticipate the adoption of this standard to have a material impact on our financial statements.

In December 2025, the FASB issued ASU 2025-12, Codification Improvements. The ASU addresses thirty-three items, representing the changes to the Codification that (1) clarify, (2) correct errors, or (3) make minor improvements. Generally, the amendments in this ASU are not intended to result in significant changes for most entities. The ASU is effective for interim reporting periods within annual reporting periods beginning in January 2027, with early adoption permitted. The adoption method of this ASU may vary, on an issue-by-issue basis. The Company is currently evaluating the impact of the ASU, but does not anticipate the adoption of this standard to have a material impact on our financial statements.

3. Fair value measurements

The carrying amount of cash and cash equivalents, accounts receivable, net and accounts payable is a reasonable approximation of fair value due to the short-term nature of these assets and liabilities. Financial liabilities that are not measured at fair value on a recurring basis include our senior secured term loan and deferred royalty financing obligation. The carrying value of our senior secured term loan approximates fair value as these borrowings are based on variable market rates. The carrying value of our deferred royalty obligation approximates fair value as the loan is recorded using the amortized cost method and considers our current estimates of future royalties expected to be paid over the estimated life of the royalty purchase agreement which are level 3 inputs, adjusted for accretion and royalty payments made by the Company during the nine months ended September 30, 2026.

On February 18, 2026 the Company issued warrants to HCR to purchase 9,834,776 common shares. The HCR warrants are measured at fair value on a recurring basis and are classified as Level 2. As of September 30, 2026 the value of the HCR warrants were $5.4 million. Fair values are estimated at the end of each reporting period with regard to the HCR warrants. The approach to the valuation follows the fair value principle, and the key input factors are described for the HCR warrants in Note 7, “Deferred royalty obligation and warrants.” A Black-Scholes model was used to calculate the fair values.

There were no transfers between the respective levels during the period.

4. Inventory

As of September 30, 2026 and December 31, 2025 inventory consisted of the following:

(1)Inventory expected to be sold beyond the Company’s 12-month operating cycle is classified as non-current inventory and recorded in inventory, long-term.

Inventory write-downs of $288 and $1,932 were recognized for the three and nine months ended September 30, 2026 respectively, and charged to cost of product sales in the Company’s unaudited condensed consolidated statements of operations. Inventory write-downs of $237 and $1,873 were recognized for the three and nine months ended September 30, 2025, respectively, and charged to cost of product sales in the Company’s unaudited condensed consolidated statements of operations.

5. Accrued expenses and other current liabilities

Accrued expenses and other current liabilities consist of the following:

6. Senior secured term loan facility and warrants

On August 15, 2022, the Company, ADCT UK and ADCT America entered into the Loan Agreement with certain affiliates and/or funds managed by each of Oaktree Capital Management, L.P. and Owl Rock Capital Advisors LLC, as lenders, and Owl Rock Opportunistic Master Fund I, L.P., as administrative agent and collateral agent, pursuant to which the Company may borrow up to $175.0 million principal amount of secured term loans, including (i) a First Tranche and (ii) Future Tranches. On August 15, 2022, the Company drew down $120.0 million principal amount of term loans under the Loan Agreement.

On August 15, 2022, the Company also issued to the lenders under the Loan Agreement warrants to purchase an aggregate of 527,295 common shares, which warrants have an exercise price of $8.30 per share (the “Lender Warrants”). Each warrant is exercisable, on a cash or a cashless basis, at the option of the holder at any time on or prior to August 15, 2032. The warrants are freestanding financial instruments that are indexed to the Company’s common stock and meet all other conditions for equity classification under ASC 480 and ASC 815. Accordingly, these warrants are recognized in equity and accounted for as a component of additional paid-in capital at the time of issuance.

On August 15, 2022, the Company also entered into the Share Purchase Agreement with the lenders under the Loan Agreement to purchase 733,568 common shares of the Company.

For the three and nine months ended September 30, 2026, the Company recorded interest expense on the senior secured term loan in the amount of $4,477 and $12,482, respectively, and $4,396 and $12,455 for the three and nine months ended September 30, 2025, respectively, which was recorded in interest expense in the unaudited condensed consolidated statements of operations. The effective interest rate (“EIR”) was 16.00% and 16.01% at September 30, 2026 and 2025, respectively.

The following table provides a summary of the interest expense for the Company’s senior secured term loan for the three and nine months ended September 30, 2026 and 2025:

The amount at which the senior secured term loan is presented as a liability in the unaudited condensed consolidated balance sheets represents the net present value of all future cash outflows associated with the loan discounted at the EIR. The carrying value of the senior secured term loan is $116.1 million and $115.5 million as of September 30, 2026 and December 31, 2025, respectively. First principal payment of $1.5 million was paid on September 30, 2026, with $7.8 million and $3.0 million due within 12 months classified as a current liability within the "Senior secured term loans, current portion” line item on the unaudited consolidated balance sheets as of September 30, 2026 and December 31, 2025, respectively.

Contractual payments due under our senior secured term loans, including exit fees are as follows (in thousands):

See Note 16, “Subsequent events” for further information.

7. Deferred royalty obligation and warrants

On August 25, 2021, the Company entered into a royalty purchase agreement with certain entities managed by HCR for up to $325.0 million. Under the terms of the agreement, the Company received gross proceeds of $225.0 million upon closing (the “First Investment Amount”) and received an additional $75.0 million during the year ended December 31, 2023 upon the first commercial sale of ZYNLONTA in the United Kingdom or any European Union country (the “Second Investment Amount”) and together with the First Investment Amount, the “Investment Amount”).

On February 18, 2026, the Company entered into an amendment (the “First HCR Amendment”) to the Purchase and Sale Agreement, dated August 25, 2021 (the “Original HCR Agreement” and, as amended by the HCR Amendment, the “Amended HCR Agreement”). Under the Original Agreement, upon the occurrence of a change of control event, the Company is obligated to pay HCR $750 million (or $675 million if HCR receives royalty payments exceeding a mid-nine-digit amount on or prior to March 31, 2029), less the amount of royalties previously paid to HCR. Under the Amended HCR Agreement, upon the occurrence of a change of control event, the Company is obligated to pay HCR $150 million (if the change of control event occurs on or before December 31, 2027) or $200 million (if the change of control event occurs on or after January 1, 2028), which amount is not reduced by the amount of royalties previously paid to HCR. In addition, following such change of control event, the royalty obligations under the Amended HCR Agreement will continue until the Royalty Cap (as defined in the Original HCR Agreement), unless the Company (or its successor in interest) buys out the remaining royalty obligations by paying HCR $525 million (if the buyout occurs on or prior to December 31, 2029) or $750 million (if the buyout occurs on or after January 1, 2030), less the amount of royalties previously paid to HCR and the change of control payment described above.

In connection with the First HCR Amendment, the Company issued to HCR warrants (the “HCR Warrants”) to purchase 9,834,776 common shares. The HCR Warrants are exercisable at any time after their original issuance until December 31, 2030. The exercise price per common share purchasable upon the exercise of the HCR Warrants is $3.81 per share, subject to customary adjustments. The HCR Warrants have certain limitations on exercise, including (i) any exercise must be for at least 50,000 common shares (or, if less, the remaining common shares available for purchase under the HCR Warrants) and (ii) cashless exercise is not available in certain circumstances as specified in the HCR Warrants. The HCR Warrants contain customary anti-dilution adjustments and will entitle holders to receive any dividends or other distributions paid on the underlying common shares prior to their expiration on an as-exercised basis. The HCR Warrants and any common shares issuable upon exercise of the warrants are not transferable on or prior to December 31, 2027, except, with respect to common shares issued upon exercise of the warrants, in connection with the consummation of certain fundamental transactions.

Accounting for the First HCR Amendment

The Company assessed the First HCR amendment for a debt extinguishment or modification in accordance with ASC-470-50. The fair value of the warrants issued was determined to be $20.8 million at the time of issuance. The First HCR amendment was accounted for as a debt modification as the present value of future cashflows of the modified agreement compared to that of the original agreement resulted in a less than 10% change. As a result, the Company did not incur any gain or loss relating to the modification. The fair value of the warrants is presented as a direct reduction to the carrying value of the debt. The Company will continue to account for the value of the debt at amortized cost.

The Company determined the fair value of the warrants at issuance on February 18, 2026 by using the Black-Scholes model with the following key assumptions:

The table below provides a rollforward of the Company’s debt obligation relating to the royalty purchase agreement.

Accounting for the HCR Warrants (First HCR Amendment)

The HCR Warrants are recognized as a warrant obligation and presented in the unaudited condensed consolidated balance sheet as a liability given the existence of a net settlement feature under which the holder may settle in cash equal to the par value, with the amount payable indexed to the CHF/USD exchange rate, and receive the underlying shares on a net basis. The warrant obligation was recorded at its initial fair value of $20.8 million at the time of issuance as described further above. Subsequent to issuance, the warrant obligation is remeasured to fair value at the end of each reporting period. Changes in the fair value (gains or losses) of the warrant obligation at the end of each period is recorded in the unaudited condensed consolidated statement of operations.

During the three and nine months ended September 30, 2026, the Company recognized expense of $1.2 million and income of $15.4 million, respectively, as a result of changes in the fair value of the warrant obligation. This amount was recorded to Other, net in the unaudited condensed consolidated statement of operations. The fair value of the warrant obligation as of September 30, 2026 was $5.4 million. See Note 12, "Other income (expense)" for further information.

The Company calculated the fair value of the HCR warrant obligation as of September 30, 2026, using the Black-Scholes model. Key inputs for the valuation of the warrant obligation were as follows:

See Note 16, “Subsequent events” for further information.

8. Pension and post-retirement benefit obligations

The Swiss employee pension plan is a defined benefit scheme that fully reinsures disability, death, and longevity risks while guaranteeing 100% of capital and interest through vested capital investment. The assets are invested by the pension plan of the collective foundation, to which many companies contribute, in a diversified portfolio that respects the requirements of the Swiss BVG.

Although, as is the case with many Swiss pension plans, the amount of ultimate pension benefit is not defined, certain legal obligations of the plan create constructive obligations on the employer to pay further contributions to fund an eventual deficit; this results in the plan nevertheless being accounted for as a defined benefit plan.

The net periodic benefit cost for the three and nine months ended September 30, 2026 and 2025 is as follows:

The components of net periodic benefit cost are included in operating expense on the unaudited condensed consolidated statements of operations.

9. Commitments and contingencies

Manufacturing Commitments

Some of our inventory components require long lead times to manufacture. Therefore, we make long-term investments in our supply chain in order to ensure we have enough drug product to meet current and future revenue forecasts. Third party manufacturing agreements include non-cancelable obligations related to the supply of ZYNLONTA. There have been no material changes related to our non-cancelable obligations under these arrangements as disclosed in our Annual Report on Form 10-K for the year ended December 31, 2025.

Contingent liabilities

From time to time, we may be involved in various legal matters generally incidental to our business. Although the results of litigation and claims cannot be predicted with certainty, after discussion with legal counsel, we are not aware of any matters for which the likelihood of a loss is probable and reasonably estimable and which could have a material impact on our consolidated financial condition, liquidity, or results of operations.

10. Revenue

The table below provides a disaggregation of revenues by type and customer location for the three and nine months ended September 30, 2026 and 2025:

(1)Europe, the Middle East and Africa

Product revenues, net

The table below provides a rollforward of the Company’s accruals related to the gross-to-net (“GTN”) sales adjustments for the three and nine months ended September 30, 2026:

The table below provides a rollforward of the Company’s accruals related to the gross-to-net (“GTN”) sales adjustments for the three and nine months ended September 30, 2025:

The table below provides the classification of the accruals related to the GTN sales adjustment included in the Company’s unaudited condensed consolidated balance sheets as of September 30, 2026 and December 31, 2025.

Customers from which we derive more than 10% of our total product revenues for the three and nine months ended September 30, 2026 and 2025 are as follows:

(1)AmerisourceBergen also operates under the name Cencora.

11. Restructuring, impairment and other related costs

On June 11, 2025, the Board of Directors approved the 2025 Restructuring to focus resources on ZYNLONTA® (loncastuximab tesirine-lpyl) expansion opportunities and the advancement of its PSMA-targeting ADC. The Company has discontinued early development efforts for the remaining preclinical programs in solid tumors. In connection with the 2025 Restructuring, the Company closed down its UK research and development facility, and has reduced its global workforce across functions by approximately 30%. The 2025 Restructuring was complete as of June 30, 2026.

On June 24, 2026, the Company announced a strategic reorganization to focus resources behind key value-driving initiatives in support of ZYNLONTA and has reduced the then-current global workforce by 17% (“2026 Restructuring”). The reduction was driven by the expected completion of the LOTIS-5 and LOTIS-7 trials this year, as well as operational efficiencies. The 2026 Restructuring was complete as of September 30, 2026.

In connection with the 2025 and 2026 Restructurings, the Company reported the following costs in restructuring, impairment and other related costs:

2026 Restructuring

Employees affected by the workforce reduction under the 2026 Restructuring are entitled to receive severance payments, continuing healthcare benefits and other employee-related costs. Costs associated with one-time termination benefits were recorded pursuant to ASC 420, while costs associated with ongoing benefit arrangements were recorded pursuant to ASC 712. As a result, the Company recorded $2.6 million to Restructuring, impairment and other related costs in the Company’s unaudited condensed consolidated statements of operations during the nine months ended September 30, 2026. The 2026 Restructuring was complete as of September 30, 2026.

See Note 17 on the Company’s Annual Report on Form 10‑K for the year ended December 31, 2025 for additional information on the 2025 Restructuring.

12. Other income (expense)

The components of interest expense for the three and nine months ended September 30, 2026 and 2025 are as follows:

The components of Other, net for the three and nine months ended September 30, 2026 and 2025 are as follows:

13. Share-based compensation

The Company has adopted various share-based compensation incentive plans. Under these plans the Company may at its discretion grant to the 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 2019 Equity Incentive Plan was adopted in November 2019 while the Conditional Share Capital Plan and the Inducement Plan were adopted in December 2023. The amounts of costs recognized for all awards for services received during the three and nine months ended September 30, 2026 were $4,145 and $12,266, with $55 and $200 capitalized to inventory, respectively. For the comparable prior-year periods, costs were $1,999 and $6,482, respectively, with no amounts capitalized to inventory.

2019 Equity Incentive Plan

In November 2019, the Company adopted the 2019 Equity Incentive Plan. Under the 2019 Equity Incentive Plan, 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 RSUs, share options, share appreciation rights, performance awards and other share-based awards. The Company has reserved 30,291,355 common shares for future issuance under the 2019 Equity Incentive Plan (including share-based equity awards granted to date less awards forfeited). On June 1, 2026, the Company issued 315,000 RSUs under the 2019 Equity Incentive Plan for the 2026 annual non-employee director equity award, which was approved by the Board of Directors. On June 30, 2026 the Company issued 629,205 RSUs under the 2019 Equity Incentive Plan for the one-time retention equity award, which was approved by the Compensation Committee and by the Board of Directors for the senior management team. No share options were issued in connection with either award. As of September 30, 2026, the Company has 9,663,922 common shares available for the future issuance of share-based equity awards.

As of September 30, 2026 and December 31, 2025, the cumulative amount recorded as a net increase to additional paid-in capital within equity on the unaudited condensed consolidated balance sheets in respect of the 2019 Equity Incentive Plan was $175,810 and $165,768, respectively. The amounts of costs recognized for all awards for services received during the three and nine months ended September 30, 2026 were $3,231 and $10,258, respectively, and $1,116 and $3,996 during the three and nine months ended September 30, 2025, respectively.

Conditional Share Capital Plan

In December 2023, the Company adopted the Conditional Share Capital Plan. Under the Conditional Share Capital Plan, 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 RSUs, share options, share appreciation rights, performance awards and other share-based awards. The Company has reserved 8,000,000 common shares for future issuance under this plan. On February 13, 2026 the Company issued 6,232,465 RSUs under the Conditional Share Capital Plan for the 2026 annual equity award, which was approved by the Compensation Committee and by the Board of Directors for the senior management team. On June 30, 2026 the Company issued 1,926,525 RSUs under the Conditional Share Capital Plan for the one-time retention equity award which was approved by the Compensation Committee and by the Board of Directors for the senior management team. No share options were issued in connection with either award. As of September 30, 2026, the Company has 534,402 common shares available for the future issuance of share-based equity awards.

As of September 30, 2026 and December 31, 2025, the cumulative amount recorded as a net increase to additional paid-in capital within equity on the unaudited condensed consolidated balance sheet in respect of the Conditional Share Capital Plan was $5,416 and $4,267. The amounts of costs for all awards recognized for services received during the three and nine months ended September 30, 2026 were $716 and $1,148, respectively, and $699 and $1,929 during the three and nine months ended September 30, 2025, respectively.

Inducement Plan

In December 2023, the Company adopted the Inducement Plan. Under the Inducement Plan, the Company may at its discretion grant to any employee who is eligible to receive an employment inducement grant in accordance with NYSE Listed Company Manual 303A.08. The maximum number of common shares in respect of which awards may be granted under the Inducement Plan is 2,000,000 common shares (including share-based equity awards granted to date, less awards forfeited), subject to adjustment in the event of certain corporate transactions or events if necessary to prevent dilution or enlargement of the benefits made available under the plan. Equity incentive awards under the Inducement Plan may be granted in the form of options, share appreciation rights, restricted shares, restricted share units, performance awards or other share-based awards but not “incentive stock options” for purposes of U.S. tax laws. As of September 30, 2026, the Company has 833,487 common shares available for the future issuance of share-based equity awards under this plan.

As of September 30, 2026 and December 31, 2025, the cumulative amount recorded as a net increase to additional paid-in capital within equity on the unaudited condensed consolidated balance sheet in respect of the Inducement Plan was $2,110 and $1,332. The amounts of costs for all awards recognized for services received during the three and nine months ended September 30, 2026 were $198 and $779, respectively, and $184 and $557 during the three and nine months ended September 30, 2025, respectively.

Share Options

Pursuant to the 2019 Equity Incentive Plan, the Conditional Share Capital Plan and Inducement Plan (the “Share-based Compensation Plans”), 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 isten years. Under the grant, the options may be settled only in common shares of the Company. Therefore, the grants of share options under the 2019 Equity Incentive Plan and Inducement Plan have been accounted for as equity-settled under U.S. GAAP. 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 statements of operations and a corresponding increase to additional paid-in capital within equity on the unaudited condensed consolidated balance sheets.

The costs recognized for services received during the three and nine months ended September 30, 2026 were $314 and $1,399, respectively, and $531 and $2,114 during the three and nine months ended September 30, 2025, respectively.

A summary of our stock option award activity for the nine months ended September 30, 2026 is as follows:

Awards outstanding as of September 30, 2026 have expiration dates through 2036. The weighted average grant date fair value of the awards granted during the nine months ended September 30, 2026 was $3.12. As of September 30, 2026, the unrecognized compensation cost related to 1,860,828 unvested share options expected to vest was $3.4 million. This unrecognized cost will be recognized over an estimated weighted-average amortization period of 1.66 years.

The exercise price of stock options granted is equal to the closing price of the common stock on the date of grant. The fair values of the options granted under the 2019 Equity Incentive Plan and the Inducement Plan were estimated on the date of the grant using the Black-Scholes option-pricing model. Expected volatility is historical volatility of our common stock. The award life for options granted was based on the time interval between the date of grant and the date during theten-year life after which, when making the grant, the Company expected on average that participants would exercise their options. The assumptions used were as follows:

RSUs

Pursuant to the Share-based Compensation Plans, 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 ofone tothree years commencing on the first anniversary of the date of grant. The RSUs may be settled only in common shares of the Company. Therefore, the grant of RSUs under both the 2019 Equity Incentive Plan and Conditional Share Capital Plan have been accounted for as equity-settled under U.S. GAAP. 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 statements of operations and a corresponding increase to additional paid-in capital within equity on the unaudited condensed consolidated balance sheets. The costs recognized for services received during the three and nine months ended September 30, 2026 were $3,831 and $10,786, respectively, and $1,468 and $4,368 during the three and nine months ended September 30, 2025, respectively. An amount ofnil and $985 was withheld for tax withholding obligations during the three and nine months ended September 30, 2026, respectively, and 250 for the three and nine months ended September 30, 2025.

The following table summarizes the RSU awards outstanding as of September 30, 2026:

(1)Includes 262,789 shares withheld to cover tax withholding obligations in connection with the vesting of RSUs previously granted.

The total fair value of RSU awards vested (as measured on the date of vesting) during the nine months ended September 30, 2026 was $6,778.

Employee Stock Purchase Plan

In June 2022, the Company adopted the 2022 Employee Stock Purchase Plan (“ESPP”), which allows eligible employees to purchase designated shares of the Company's common shares at a discount, over a series of offering periods through accumulated payroll deductions. The Company offers the ESPP to employees twice a year with each having asix-month offering period. The first offering period is generally from January 1st through June 30th and the second offering period is from July 1st through December 31st. The grant date is the first day of each offering period.

The costs recognized related to the ESPP during the three and nine months ended September 30, 2026 werenil and $81 respectively, andnil during the three and nine months ended September 30, 2025.

14. Loss per share

The basic loss per share is calculated by dividing the net loss attributable to shareholders by the weighted average number of shares in issue during the period, excluding common shares owned by the Company and held as treasury shares, as follows:

For the three and nine months ended September 30, 2026 and 2025, basic and diluted loss per share are calculated on the weighted average number of shares issued and outstanding, and also considers in the calculation the Company’s outstanding Pre-funded warrants, which were 27,680,776 and 23,897,532 as of September 30, 2026 and 2025, respectively. The calculation excludes shares to be issued under the Share-based Compensation Plans, the Company’s warrants issued in connection with the senior secured term loan facility and the Company’s HCR warrants and shares to be issued under the 2022 ESPP as the effect of including those shares would be anti-dilutive. See Note 6, “Senior secured term loan facility and warrants,” Note 7, “Deferred royalty obligation and warrants” and Note 13, “Share-based compensation,” for further information.

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:

15. Segment reporting

The Company is managed and operated asone reportable segment, which includes all global activities related to the development and commercialization of targeted ADC cancer therapies. The determination of a single reportable segment is consistent with the consolidated financial information regularly provided to the Company’s chief operating decision maker (“CODM”), which is its chief executive officer. The CODM uses loss from operations and consolidated net loss for purposes of assessing performance, making operating decisions, allocating resources and planning and forecasting for future periods. The CODM allocates resources and plans for the long-term growth of the Company based on the Company's available cash resources, forecasted cash flow, and expenditures on a consolidated basis, as well as an assessment of the probability of success of its research and development activities. Resource allocation and long-term growth decisions are informed by budgeted and forecasted expense information, along with actual expenses incurred to date. The measure of segment assets is reported on the consolidated balance sheets as total assets.

The following table is the summary of the segment profit or loss information, including the significant expense categories for the three and nine months ended September 30, 2026 and 2025, respectively:

(1)Excludes share-based compensation.

(2)Includes Other expense, net, and Income tax expense.

16. Subsequent events

October 2026 Private Placement

On October 7, 2026, the Company entered into securities purchase agreements for the sale of its equity securities to certain institutional investors. In the private placement, the Company sold 12,911,347 common shares at $1.42 per share, and pre-funded warrants (the “October 2026 Pre-Funded Warrants”) to purchase 48,088,653 common shares at $1.32 per pre-funded warrant, which is the price per common share in the private placement minus the exercise price of CHF 0.08 per pre-funded warrant (collectively, the “October 2026 Private Placement”). The private placement closed on October 22, 2026. Gross proceeds from the October 2026 Private Placement were $82.0 million, and, after giving effect to approximately $5.7 million of transaction costs related to the private placement, net proceeds were approximately $76.3 million.

The October 2026 Pre-Funded Warrants are exercisable, on a cash or cashless basis, at the option of the holder after the date of issuance until the tenth anniversary of their original issuance. At any time during the last 90 days of the term, the holder may exchange the October 2026 Pre-Funded Warrant for, and we will issue, a new pre-funded warrant for the number of common shares then remaining under the October 2026 Pre-Funded Warrant. The October 2026 Pre-Funded Warrants have certain limitations on exercise, including (i) any exercise must be for at least 50,000 common shares (or, if less, the remaining common shares available for purchase under the October 2026 Pre-Funded Warrants), (ii) a holder cannot exercise for any amount that would cause such holder’s beneficial ownership of our common shares to exceed 9.99% (or 19.99% with 61-days’ notice to us), and (iii) cashless exercise is not available in certain circumstances as specified in the October 2026 Pre-Funded Warrants. The warrants contain customary anti-dilution adjustments and will entitle holders to receive any dividends or other distributions paid on the underlying common shares prior to their expiration on an as-exercised basis.

The Company is currently in the process of evaluating the accounting treatment of the October 2026 Private Placement and pre-funded warrants.

Amendment to the Loan Agreement

On October 7, 2026, the Company, certain subsidiaries of the Company, the lenders party thereto and Blue Owl Opportunistic Lending Master Fund I, L.P., as administrative agent and collateral agent, entered into a second amendment (the “Loan Agreement Amendment”) to the Loan Agreement and Guaranty, dated August 15, 2022 (as amended from time to time, the “Loan Agreement”). Following the satisfaction of all closing conditions, including the prepayment of $70.0 million principal amount of term loans under the Loan Agreement (inclusive of the Company’s September 30, 2026 amortization payment plus related accrued interest, fees, and premiums), the Loan Agreement Amendment became effective. Immediately following the prepayment, the remaining principal amount of outstanding term loans was $50.0 million. The Loan Agreement Amendment eliminated subsequent scheduled principal amortization, leaving the remaining principal payable at maturity unless earlier accelerated; eliminated the minimum liquidity covenant; and set the minimum trailing four-quarter U.S. ZYNLONTA sales covenant at $65.0 million for the quarter ending December 31, 2026 and each quarter thereafter.

In connection with the Loan Agreement Amendment, the Company entered into amendments to the Lender Warrants to purchase an aggregate of 527,295 common shares, which were issued on August 15, 2022 in connection with the Loan Agreement. The amendments reduce the exercise price of the Lender Warrants from $8.30 per share to $1.00 per share. The amendments to the Lender Warrants became effective on October 22, 2026, upon the effectiveness of the Loan Agreement Amendment.

The Company is currently in the process of evaluating the accounting treatment for the Loan Agreement Amendment.

Amendment to the Royalty Purchase and Sale Agreement

On October 7, 2026, the Company entered into Amendment No. 2 (the “Second HCR Amendment”) to its Purchase and Sale Agreement, dated August 25, 2021 (as amended from time to time, the “HCR Agreement”), with certain entities managed by Healthcare Royalty Management, LLC (collectively, “HCR”). To date, HCR has provided $300 million of funding to the Company. The Second HCR Amendment eliminates the payment otherwise required solely upon a change of control and permits the Company (or its successor in interest) to exercise its option to buy out the remaining royalty obligations without a change of control by paying HCR $525 million (if the buyout occurs on or prior to December 31, 2029) or $750 million (if the buyout occurs on or after January 1, 2030), less the amount of royalties previously paid to HCR. If this option is not exercised, the royalty obligations under the HCR Agreement will continue until the Royalty Cap (as defined in the HCR Agreement). In addition, the Second HCR Amendment reduces the aggregate outstanding principal amount of third-party indebtedness of the Company and its subsidiaries are permitted to incur to $50.0 million. An uncured breach of this debt limitation covenant entitles HCR to elect to receive the non-performance payment equaling 1.5 times the difference between the $300 million aggregate purchase price and royalty payments and other qualifying credited amounts actually received by HCR, subject to a cure period. The

Second HCR Amendment also requires the Company, subject to shareholder approval and applicable legal and fiduciary duties limitations, to use its best efforts to become a Delaware corporation.

In addition, the Second HCR Amendment amends the HCR Warrants to purchase 9,834,776 common shares, which were issued on February 18, 2026 in connection with the First HCR Amendment, by reducing the exercise price of the HCR Warrants from $3.81 per share to $0.10 per share; by adding a provision that prohibits the exercise of the HCR Warrants if, upon giving effect to such exercise, the aggregate number of the Company’s common shares beneficially owned by the holder (together with its affiliates and certain attribution parties) would exceed 4.99% (or,61 days after a written notice from such holder, any other percentage not in excess of 9.99%) of the number of the Company’s common shares outstanding immediately after giving effect to the exercise, as such percentage ownership is determined in accordance with the terms of the Second HCR Amendment; and removing the contractual restrictions on transfers of the HCR Warrants and shares issuable upon exercise of the HCR Warrants before January 1, 2028. The Second HCR Amendment became effective on October 22, 2026, upon the concurrent completion of the October 2026 Private Placement and the effectiveness of the Loan Agreement Amendment.

The Company is currently in the process of evaluating the accounting treatment for the Second HCR Amendment.