Cullinan Therapeutics, Inc.

Item 7.01 Regulation FD Disclosure. On October 1, 2026, Cullinan Therapeutics, Inc. (the "Company") issued a press release announcing the initiation of a new drug application ("NDA") submission to the United States Food and Drug Administration (the "FDA") for zipalertinib in combination with platinum-based chemotherapy for the treatment of patients with previously untreated, locally advanced or metastatic non-small cell lung cancer ("NSCLC") harboring epidermal growth factor receptor ("EGFR") exon 20 insertion ("ex20ins") mutations under the FDA's Real-Time Oncology Review Program ("RTOR"). A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference. The information in this Current Report on Form 8-K furnished pursuant to Item 7.01, including Exhibit 99.1 attached hereto, shall not be deemed to be "filed" for the purposes of Section 18 of the Exchange Act, or otherwise subject to the liabilities of that section and will not be incorporated by reference into any filing by the Company under the Securities Act or the Exchange Act, unless specifically identified as being incorporated therein by reference.

Item 8.01 Other Events. On October 1, 2026, the Company announced the initiation of a NDA submission to the FDA for zipalertinib in combination with platinum-based chemotherapy for the treatment of patients with previously untreated, locally advanced or metastatic NSCLC harboring EGFR ex20ins mutations under the FDA’s RTOR program. The RTOR program allows sponsors to submit clinical data in advance of the complete application to facilitate earlier review of efficacy and safety results. Completion of the Company's NDA submission is expected by year-end 2026. The NDA submission is based on data from the Phase 3 REZILIENT3 trial, which met its primary endpoint, demonstrating a statistically significant and clinically meaningful improvement in median progression-free survival for zipalertinib plus chemotherapy compared to chemotherapy alone. These results were recently presented at the International Association for the Study of Lung Cancer’s 2026 World Conference on Lung Cancer during a Presidential Symposium. Zipalertinib holds FDA Breakthrough Therapy designation for the treatment of patients with locally advanced or metastatic EGFR ex20ins NSCLC who have previously received platinum-based chemotherapy. An NDA seeking accelerated approval for zipalertinib monotherapy in this indication remains under FDA review, with a Prescription Drug User Fee Act target action date of February 27, 2027. The Company is eligible to receive (i) a $30.0 million payment from Taiho upon U.S. regulatory approval of zipalertinib for the treatment of patients with locally advanced or metastatic EGFR ex20ins NSCLC who have previously received platinum-based systemic chemotherapy, and (ii) up to a $100.0 million payment from Taiho upon U.S. regulatory approval of zipalertinib for the first-line treatment for adult patients with locally advanced or metastatic EGFR ex20ins NSCLC.