Daiichi Sankyo and MSD Withdraw Ifinatamab Deruxtecan FDA Filing

Daiichi Sankyo and MSD have voluntarily withdrawn their U.S. Biologics License Application (BLA) for ifinatamab deruxtecan in adults with extensive-stage small cell lung cancer (ES-SCLC) whose disease has progressed after platinum-based chemotherapy.

The companies said the decision followed discussions with the U.S. Food and Drug Administration (FDA), which indicated that the available data did not meet the requirements for accelerated approval. The application was supported in part by results from the Phase 2 IDeate-Lung01 trial.

The FDA’s accelerated approval pathway can allow medicines for serious diseases to reach patients earlier based on surrogate measures that are considered reasonably likely to predict clinical benefit. In this case, the companies said the current dataset was not sufficient to support approval under the pathway.

Despite the withdrawal, development of ifinatamab deruxtecan is continuing. Patient enrollment remains underway in the Phase 3 IDeate-Lung02 trial, which is evaluating the drug against physician’s choice of chemotherapy in patients with relapsed ES-SCLC.

The trial is studying patients whose disease has progressed after one prior line of platinum-based chemotherapy. Treatment options in the control group include amrubicin, lurbinectedin or topotecan.

Ifinatamab deruxtecan is a B7-H3-directed antibody-drug conjugate (ADC) developed using Daiichi Sankyo’s DXd technology. The companies are investigating the treatment as a potential new option for patients with difficult-to-treat cancers.

Daiichi Sankyo said enrollment in IDeate-Lung02 is nearing completion. The results from the Phase 3 study could provide data for a potential future regulatory filing in the U.S. and other markets.

The companies are also evaluating ifinatamab deruxtecan in other cancers. Two additional Phase 3 trials are underway: IDeate-Prostate01 in patients with castration-resistant prostate cancer and IDeate-Esophageal01 in patients with esophageal squamous cell carcinoma.

The withdrawal of the current BLA does not end the clinical development program. Daiichi Sankyo and MSD said they will continue evaluating ifinatamab deruxtecan in small cell lung cancer and other advanced or metastatic cancers.