On November 20, 2025 Taiho Oncology, Inc., Taiho Pharmaceutical Co., Ltd., and Cullinan Therapeutics, Inc. (Nasdaq: CGEM) reported the companies have initiated the rolling submission of a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) seeking accelerated approval of zipalertinib, an oral epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, for the treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) with EGFR exon 20 insertion (ex20ins) mutations who have previously received platinum-based systemic chemotherapy.

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Zipalertinib previously received Breakthrough Therapy Designation in 2021, which with FDA agreement, allows submission of portions of the application as they are completed. The companies anticipate completion of the NDA submission in the first quarter of 2026 with an associated request for priority review.

The NDA submission is based on the primary efficacy data from the REZILIENT1 trial, a Phase 1/2 clinical trial of zipalertinib (development code: CLN-081/TAS6417) monotherapy in patients with NSCLC harboring EGFR ex20ins mutations who have received prior therapy.

Positive results from the REZILIENT1 trial were presented at the 2025 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting and were simultaneously published in the Journal of Clinical Oncology.

About REZILIENT1
REZILIENT1 (Researching Zipalertinib In EGFR Non-Small Cell Lung Cancer Tumors) is a Phase 1/2 clinical trial (NCT04036682) to evaluate efficacy and safety of zipalertinib in adult patients with locally advanced or metastatic NSCLC harboring EGFR ex20ins mutations who have received prior therapy. Patients were treated with oral zipalertinib 100 mg twice daily. The primary endpoints were objective response rate (ORR) and duration of response (DOR) as assessed by blinded independent central review (ICR) per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Adverse events were characterized and graded according to the NCI-Common Terminology Criteria for Adverse Events (CTCAE v5.0).

About Zipalertinib
Zipalertinib (development code: CLN-081/TAS6417) is an orally available small molecule designed to target activating mutations in EGFR. The molecule was selected because of its ability to inhibit EGFR variants with exon 20 insertion mutations, while sparing wild-type EGFR. Zipalertinib is designed as a next generation, irreversible EGFR inhibitor for the treatment of a genetically defined subset of patients with non-small cell lung cancer. Zipalertinib has received Breakthrough Therapy Designation from the FDA. Zipalertinib is investigational and has not been approved by any health authority.

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

About EGFR Exon 20 Insertion Mutations
NSCLC is a common form of lung cancer and up to 4% of all cases globally have EGFR exon 20 insertions, which makes them the third most common EGFR mutation subtype.1 In the United States, approximately 16% of patients with NSCLC harbor EGFR mutations,2 with insertions at exon 20 accounting for up to 12% of these mutations.

(Press release, Taiho, NOV 20, 2025, View Source [SID1234660855])