Daiichi Sankyo and Merck withdraw US BLA for ifinatamab deruxtecan in ES‑SCLC

Regulatory action

Daiichi Sankyo and Merck have voluntarily withdrawn the Biologics License Application seeking accelerated approval in the US for ifinatamab deruxtecan (I‑DXd) in adult patients with extensive‑stage small cell lung cancer (ES‑SCLC) after disease progression on or after platinum‑based chemotherapy.

Reason for withdrawal

The withdrawal follows discussions with the US FDA, which determined that the data submitted to support accelerated approval — including results from the IDeate‑Lung01 Phase 2 study — do not satisfy the agency’s requirements for the proposed indication.

Ongoing development

Patient enrollment continues in the IDeate‑Lung02 Phase 3 trial, which is evaluating I‑DXd versus physician’s choice chemotherapy (amrubicin, lurbinectedin or topotecan) in patients with relapsed ES‑SCLC after one prior platinum‑based line and is near completion. Two additional Phase 3 studies are ongoing: IDeate‑Prostate01 in castration‑resistant prostate cancer and IDeate‑Esophageal01 in esophageal squamous cell carcinoma.

Drug profile and Phase 2 details

Ifinatamab deruxtecan is an investigational B7‑H3 directed antibody‑drug conjugate using Daiichi Sankyo’s DXd payload technology. IDeate‑Lung01 was a global Phase 2, randomized, open‑label, two‑part trial that enrolled 187 patients across Asia, Europe and North America; dose optimization compared 8 mg/kg versus 12 mg/kg every three weeks, with expansion at 12 mg/kg. The primary endpoint was objective response rate by blinded independent central review per RECIST v1.1; secondary endpoints included duration of response, progression‑free survival, overall survival and safety.

Regulatory designations

I‑DXd has been granted orphan drug designation for SCLC by the US FDA, European Commission, Japan MHLW and Taiwan FDA, and an FDA orphan designation for esophageal cancer.