Current Report · Items 7.01, 8.01, 9.01 · 8-K

Cullinan Therapeutics, Inc.

CGEMNASDAQEQUITYCurrent

Regulation FD Disclosure · Other Events

Filed Sep 24, 2026Accepted Sep 24, 2026, 7:15 AM EDTCIK 1789972Accession 0001193125-26-400144

Company context

Cullinan Therapeutics, Inc. (Nasdaq: CGEM) is a biopharmaceutical company developing potential first- or best-in-class, disease-modifying T cell engagers for autoimmune diseases and cancer. Cullinan pursues promising therapeutic targets while leveraging core expertise in T cell engagers, which are established in oncology and are now advancing into autoimmune diseases. With a clinical-stage pipeline built on a rigorous scientific approach and purposeful innovation, Cullinan is advancing its mission to deliver new standards of care for patients. Learn more about Cullinan at https://cullinantherapeutics.com/, and follow Cullinan on LinkedIn and X.

Current securities

CGEMNASDAQ · EQUITY · Current

Recent company filings

Disclosure sections

Items 7.01, 8.01, 9.01

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Item 7.01Item 7.01 - Regulation FD Disclosure

Item 7.01 Regulation FD Disclosure. On September 24, 2026, Cullinan Therapeutics, Inc. (the "Company") issued a press release outlining anticipated milestones for the fourth quarter of 2026. 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 8.01Item 8.01 - Other Events

Item 8.01 Other Events. On September 24, 2026, the Company outlined its plans to share the following immunology and oncology pipeline updates in the fourth quarter of 2026. Immunology CLN-978 • The Company plans to share both multi-dose and single target dose regimen data from each of its ongoing Phase 1 clinical trials of CLN-978 in patients with (i) treatment-refractory moderate to severe systemic lupus erythematosus ("SLE"), (ii) difficult-to-treat rheumatoid arthritis ("RA") and (iii) treatment-refractory moderate to severe Sjögren's disease in December. Velinotamig • The Company plans to share multi-dose regimen data from the ongoing Phase 1 dose escalation portion of the clinical trial of velinotamig in patients with SLE being conducted by Chongqing Genrix Biopharmaceutical Co., Ltd. in China in a poster session at American College of Rheumatology Convergence 2026 in November. Oncology CLN-049 • The Company plans to share updated data from the dose escalation portion of its ongoing Phase 1 trial of CLN-049 in patients with relapsed/refractory acute myeloid leukemia in December.

Filed exhibits (1)

EX-99.1 (by filename) cgem-ex99_1.htm

Exhibit 99.1 Cullinan Therapeutics Highlights Fourth Quarter 2026 Milestones Across Immunology and Oncology T Cell Engager Portfolio Velinotamig (BCMA TCE) multi-dose regimen data in SLE at ACR Convergence 2026 in November CLN-978 (CD19 TCE) multi-dose regimen data in SLE, RA and Sjögren’s disease in December CLN-049 (FLT3 TCE) updated data from the Phase 1 dose escalation study in December CAMBRIDGE, Mass. September 24, 2026 (GLOBE NEWSWIRE) -- Cullinan Therapeutics, Inc. (Nasdaq: CGEM; “Cullinan”), a clinical-stage biopharmaceutical company accelerating potential first- or best-in-class, disease-modifying T cell engagers in autoimmune diseases and cancer, today outlined fourth quarter 2026 milestones across its immunology and oncology pipeline. “We look forward to providing several updates across our T cell engager programs in the fourth quarter of 2026. Starting with autoimmune diseases, for CLN-978 we look forward to sharing the most comprehensive clinical data set to date for a CD19 T cell engager across all indications, with multi-dose regimen data reported concurrently for SLE, RA, and now Sjögren’s disease also. For velinotamig, we will provide multi-dose regimen data…

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