Taiho Oncology Inc, the US subsidiary of Japan's Taiho Pharmaceutical Co Ltd, and US biopharmaceutical company Cullinan Therapeutics Inc (Nasdaq: CGEM) announced on Sunday the publication of positive results from the REZILIENT1 trial in the peer-reviewed Journal of Clinical Oncology (JCO).

REZILIENT1 is a Phase 1/2, global, multicentre study of zipalertinib (development code: CLN-081/TAS6417) in patients with non-small cell lung cancer (NSCLC) harbouring epidermal growth factor receptor (EGFR) exon 20 insertion mutations (ex20ins) who have received prior therapy. Results from the trial will be presented in a simultaneous oral presentation at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract #8503).

According to the companies, zipalertinib demonstrated clinically meaningful efficacy in the primary efficacy population (n=176), including 51 patients who had received prior amivantamab. The confirmed objective response rate (ORR) was 35.2% overall, and median duration of response (mDOR) and progression-free survival were 8.8 months and 9.4 months, respectively. In patients treated after prior platinum-based chemotherapy only (n=125), ORR was 40% with mDOR of 8.8 months. The safety profile of zipalertinib was manageable and consistent with previously reported data.

Further exploratory subgroup analyses revealed that patients who had received prior amivantamab without other ex20ins-targeted therapy showed a confirmed ORR of 30% and mDOR of 14.7 months. Patients with brain metastases showed a confirmed ORR of 30.9% and a mDOR of 8.3 months.

Taiho Oncology is currently recruiting patients in the Phase 3 REZILIENT3 trial.

Zipalertinib is being developed by Taiho Oncology Inc and its parent company, Taiho Pharmaceutical Co Ltd in collaboration with Cullinan Therapeutics Inc in the United States.