Cullinan Therapeutics Shares Fall 6.3% After Phase 3 Zipalertinib Trial Results

Cullinan Therapeutics (NASDAQ:CGEM) shares fell 6.3% on Monday after the company and its partners reported Phase 3 results for zipalertinib in patients with a form of non-small cell lung cancer.

Cullinan, Taiho Oncology and Taiho Pharmaceutical said the REZILIENT3 trial met its primary endpoint, with zipalertinib plus chemotherapy extending median progression-free survival by 6.0 months compared with chemotherapy alone.

The results were presented at the World Conference on Lung Cancer in Seoul, South Korea.

Median Progression-Free Survival Reaches 14.5 Months

The Phase 3 trial enrolled 279 patients with advanced non-small cell lung cancer carrying EGFR exon 20 insertion mutations who had not previously received treatment for advanced disease.

Patients receiving zipalertinib at 100 mg twice daily in combination with chemotherapy had median progression-free survival of 14.5 months, compared with 8.5 months for patients receiving chemotherapy alone. The hazard ratio was 0.50.

The objective response rate was 65.0% in the zipalertinib combination group and 40.3% in the chemotherapy-only group.

At an interim analysis of overall survival with 30% event maturity, the hazard ratio for death was 0.72 for the combination compared with chemotherapy alone. Overall survival follow-up is continuing.

Companies Report Safety Findings

The companies said the adverse-event profile for zipalertinib plus chemotherapy was generally consistent with the known safety profiles of the individual treatments.

Grade 3 or higher adverse events were reported in 87.1% of patients receiving the combination, compared with 54.4% of patients treated with chemotherapy alone. The companies described the higher-grade adverse events as primarily manageable haematological events.

The REZILIENT3 data were presented during a Presidential Symposium at the conference. Cullinan and its partners said they plan to discuss the results with health authorities regarding potential availability of zipalertinib to patients.

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