Daiichi Sankyo and Merck Withdraw Lung Cancer Drug Application

Daiichi Sankyo and Merck have withdrawn their application for accelerated approval of ifinatamab deruxtecan in the US. The decision follows discussions with the FDA, which found that data from the IDeate-Lung01 Phase 2 trial did not meet requirements for accelerated approval.

The application targeted treatment of adult patients with extensive-stage small cell lung cancer who had disease progression on or after platinum-based chemotherapy. Ifinatamab deruxtecan is an investigational B7-H3 directed antibody-drug conjugate that has received orphan drug designation from the FDA and other regulatory authorities.

Patient enrollment continues in the IDeate-Lung02 Phase 3 trial, which evaluates the efficacy and safety of ifinatamab deruxtecan versus chemotherapy options. The companies are conducting two additional Phase 3 trials with ifinatamab deruxtecan in advanced or metastatic disease.

Approximately 27,000 new cases of small cell lung cancer were diagnosed in the US in 2025, accounting for about 12% of all lung cancer cases. Daiichi Sankyo's head of therapeutic area oncology development, Abderrahmane Laadem, said enrollment into the IDeate-Lung02 Phase 3 trial is near completion and they look forward to assessing the potential for a future filing with the FDA based on those results.