Significant accounting policies (Policies)	9 Months Ended
Sep. 30, 2023
Accounting Policies, Changes in Accounting Estimates And Errors [Abstract]
Statement of Compliance	Statement of Compliance These unaudited condensed consolidated interim financial statements as of and for the three and 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.
Functional and reporting currency	Functional and reporting currency These unaudited condensed consolidated interim financial statements are presented in United States Dollars (“USD” or “$”), which is the Company’s functional currency and the Group’s reporting currency.
Use of estimates and judgements	Use of estimates and judgements The preparation of the unaudited condensed consolidated interim financial statements in conformity with IAS 34 requires management to make judgements, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets and liabilities, income and expense. Actual results may differ from these estimates. Estimates are based on management’s knowledge of current events and actions that the Company may undertake in the future. Estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period in which the estimate is revised if the revision affects only that period, or in the period of the revision and future periods if the revision affects both current and future periods. In preparing these unaudited condensed consolidated interim financial statements, the significant judgements made by management in applying the Group’s accounting policies and the key sources of estimation uncertainty included those that applied to the consolidated financial statements for the year ended December 31, 2022. There have been no material changes to the use of estimates and judgements other than those described in note 3, "Significant accounting policies."
Revenue Recognition	Revenue Recognition 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. 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.
New and amended IFRS standards	New and amended IFRS standards There are no new IFRS standards, amendments to standards or interpretations that are mandatory for the financial year beginning on January 1, 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.

Significant accounting policies (Policies)

9 Months Ended

Sep. 30, 2023

Accounting Policies, Changes in Accounting Estimates And Errors [Abstract]

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.

Functional and reporting currency

These unaudited condensed consolidated interim financial statements are presented in United States Dollars (“USD” or “$”), which is the Company’s functional currency and the Group’s reporting currency.

Use of estimates and judgements

The preparation of the unaudited condensed consolidated interim financial statements in conformity with IAS 34 requires management to make judgements, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets and liabilities, income and expense. Actual results may differ from these estimates.

Estimates are based on management’s knowledge of current events and actions that the Company may undertake in the future. Estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period in which the estimate is revised if the revision affects only that period, or in the period of the revision and future periods if the revision affects both current and future periods.

In preparing these unaudited condensed consolidated interim financial statements, the significant judgements made by management in applying the Group’s accounting policies and the key sources of estimation uncertainty included those that applied to the consolidated financial statements for the year ended December 31, 2022. There have been no material changes to the use of estimates and judgements other than those described in note 3, "Significant accounting policies."

Revenue Recognition

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.

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.

New and amended IFRS standards

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