Taiho completes FDA NDA submission for zipalertinib plus chemotherapy in first-line EGFR exon 20 insertion-positive NSCLC, supported by Phase 3 REZILIENT3 results showing a six-month PFS improvement.
Written By: Umesh Hanumante, M.Pharm (RA)
Reviewed By: Pharmacally Editorial Team
Taiho Oncology has completed a New Drug Application (NDA) submission to the US Food and Drug Administration (FDA) for zipalertinib in combination with platinum-based chemotherapy for previously untreated, locally advanced or metastatic non-small cell lung cancer (NSCLC) harbouring epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations.
Announced on November 12, 2026, the submission follows the positive Phase 3 REZILIENT3 trial and was made under the FDA’s Real-Time Oncology Review (RTOR) programme. The completed application will undergo FDA review, with a Prescription Drug User Fee Act (PDUFA) target action date to be assigned if the application is accepted.
REZILIENT3 Demonstrates a Six-Month PFS Improvement
The NDA is supported by REZILIENT3 (NCT05973773), which met its primary endpoint at an interim analysis, demonstrating a statistically significant improvement in progression-free survival (PFS) with zipalertinib plus chemotherapy compared with chemotherapy alone.
Median PFS, assessed by blinded independent central review, was 14.5 months with the combination versus 8.5 months with chemotherapy alone (hazard ratio [HR], 0.50; 95% CI, 0.34–0.73; p=0.00015). This represents a 50% reduction in the risk of disease progression or death.
The combination also improved other measures of antitumour activity. The objective response rate (ORR) was 65.0% compared with 40.3% in the chemotherapy-alone group, while median duration of response was 14.2 months versus 9.9 months, respectively.
However, the overall survival (OS) findings remain immature. At an interim analysis with approximately 30% maturity, the HR for death was 0.72 (95% CI, 0.42–1.23). Further follow-up will be required to establish whether the PFS improvement translates into an overall survival benefit.
Safety Profile and Treatment Considerations
The combination demonstrated greater treatment-related toxicity than chemotherapy alone. Grade 3 or higher adverse events occurred in 87.1% of patients receiving zipalertinib plus chemotherapy, compared with 54.4% in the control group. The difference was primarily driven by haematological adverse events.
Grade 3 or higher EGFR-related toxicities in the combination group included rash (10.7%) and diarrhoea (1.4%). No new safety signals were reported.
These findings indicate that the efficacy improvement needs to be considered alongside the higher incidence of severe adverse events when assessing the regimen’s potential role in first-line treatment.
FDA Review and Commercial Implications
The RTOR programme allows sponsors to submit clinical data ahead of the complete NDA, enabling the FDA to begin reviewing key efficacy and safety information earlier in the submission process. However, completion of the application does not establish FDA acceptance or approval.
The regulatory development also has commercial implications for Cullinan Therapeutics, Taiho Oncology’s US development partner. Cullinan is eligible to receive milestone payments of $30 million upon US regulatory approval in the second-line setting and $100 million upon approval in the first-line setting.
Zipalertinib, also known as CLN-081 or TAS6417, is an oral, irreversible, next-generation EGFR inhibitor designed to target activating EGFR mutations, including exon 20 insertions. The investigational drug has not been approved by any health authority.
First-Line Treatment Opportunity
EGFR exon 20 insertion mutations account for up to 4% of NSCLC cases globally, representing a molecularly defined patient population with distinct treatment considerations.
The completion of the NDA submission moves the zipalertinib combination programme into the next stage of regulatory evaluation. REZILIENT3 provides evidence of improved disease control and response rates over chemotherapy alone. Nevertheless, the immature survival data and higher incidence of severe adverse events remain important considerations as the FDA evaluates the application.
The regulatory outcome will determine whether these Phase 3 findings can translate into a new first-line treatment option for patients with EGFR exon 20 insertion-positive advanced NSCLC.
References
New Drug Application Submission Completed for Zipalertinib Plus Chemotherapy in First-Line EGFR Exon 20 Insertion Mutation Non-Small Cell Lung Cancer, Cullinan Therapeutics, November 12, 2026.
REZILIENT3 (REsearching ZIpaLertinib In EGFR Non-small Cell Lung Cancer Tumors) (REZILIENT3), ClinicalTrials.gov ID NCT05973773
About the Writer
Umesh Hanumante (M.Pharm) (LinkedIn) is a pharmacy professional and healthcare writer with a background in Regulatory Affairs, pharmaceutical innovation, and clinical research. He has around two years of industry experience as an Executive PMT at Troikaa Pharmaceuticals Ltd and qualified GPAT 2024. His areas of interest include regulatory compliance, dossier preparation, clinical trials, emerging therapies, and advancements in the global pharmaceutical and healthcare sector.