Ifinatamab Deruxtecan Shows 48.2% Response in ES-SCLC Phase 2 Trial by Daiichi Sankyo and Merck
- Ifinatamab deruxtecan showed a 48.2% objective response rate in 137 ES-SCLC patients.
- The trial reported a median duration of response of 5.3 months and overall survival of 10.3 months.
- Breakthrough Therapy Designation was granted by the FDA in August 2025.
- Safety profile consistent with Phase 1, with 36.5% experiencing grade 3 or higher adverse events.
Trial Results
Ifinatamab deruxtecan demonstrated a 48.2% objective response rate in 137 patients with previously treated extensive-stage small cell lung cancer (ES-SCLC). The trial reported a median duration of response of 5.3 months and a disease control rate of 87.6%.
Subgroup Analysis
In a subset of 32 patients receiving the drug as a second-line treatment, a 56.3% response rate was observed. For 105 patients in a third-line setting, the response rate was 45.7%. An intracranial response rate of 46.2% was noted in patients with brain metastases.
Regulatory Status
The U.S. FDA granted Breakthrough Therapy Designation to ifinatamab deruxtecan in August 2025 for ES-SCLC patients with disease progression after platinum-based chemotherapy.
Safety Profile
The safety profile was consistent with Phase 1 results, with 36.5% of patients experiencing grade 3 or higher treatment-related adverse events. Common adverse events included neutropenia, lymphopenia, and anemia. Seventeen patients had confirmed treatment-related interstitial lung disease or pneumonitis.
Source: Merck