Merck and Daiichi Sankyo Withdraw I-DXd BLA in ES-SCLC Citing Insufficient Data

The biologics license application (BLA) for ifinatamab deruxtecan (I-DXd) in extensive-stage small cell lung cancer (ES-SCLC) has been voluntarily withdrawn by Merck and Daiichi Sankyo. This decision follows discussions with the FDA, which found that the supporting data from the phase 2 IDeate-Lung01 trial do not meet the requirements for accelerated approval. The company plans to examine a potential future filing based on results from the ongoing phase 3 IDeate-Lung02 trial.

According to Marjorie Green, MD, senior vice president and head of oncology at Merck Research Laboratories, the companies are 'disappointed that the current dataset are not supportive of an approval at this time.' The BLA was accepted by the FDA in April 2026 and granted priority review. I-DXd showed a confirmed objective response rate (ORR) of 48.2% in patients with ES-SCLC, but the median progression-free survival (PFS) was only 4.9 months.

The safety profile of I-DXd included any-grade treatment-emergent adverse effects in 98.5% of patients, grade 3 TEAEs in 62.0%, and serious TEAEs in 39.4%. The most common any-grade TEAEs were nausea (48.2%), anemia (45.3%), decreased appetite (38.7%), and neutropenia (38.0%).