and Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act") or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Other Events. CLN-978 On June 10, 2026, the Company shared updated clinical data from its Phase 1 OUTRACE clinical trials for CLN-978 in patients with treatment-refractory RA (“OUTRACE RA”) and in patients with treatment-refractory moderate to severe SLE (“OUTRACE SLE”). As of May 20, 2026, new multi-dose data in the Phase 1 OUTRACE RA clinical trial demonstrate the robust efficacy profile of CLN-978 observed in two heavily pre-treated, poly-refractory patients, including a DAS28-ESR remissio…

Other Events. On June 6, 2026, the Company shared initial clinical data from its Phase 1 OUTRACE clinical trials for CLN-978 in patients with treatment-refractory RA ("OUTRACE RA") and in patients with treatment-refractory moderate to severe SLE ("OUTRACE SLE"). As of May 15, 2026, 29 patients had been evaluated across various dose levels in the OUTRACE SLE and RA clinical trials. SLE (n=18) RA (n=11) Dose levels investigated Safety PD* Efficacy Safety PD* Efficacy Cohort 1 (D1: 10 μg) 3 3 3…

Other Events. On May 18, 2026, the Company announced initial clinical data from its Phase 1 OUTRACE Program for CLN-978 in patients with treatment-refractory RA and in patients with treatment-refractory moderate to severe SLE. As of a January 14, 2026 cutoff date, 14 patients were dosed across the RA (cohorts 1-3, n=5) and SLE (cohorts 1-3, n=9) clinical trials. All day 1 step up doses were 10 micrograms (“mcg”) and day 8 target doses were either 20 mcg (cohort 2) or 30 mcg (cohort 3). Follow…

and Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act") or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

and Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act") or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Other Events. On January 8, 2026, the Company provided an update on the anticipated program milestones for 2026 as set out below. Immunology CLN-978 • In the Company's Phase 1 OUTRACE study in patients with active, difficult-to-treat rheumatoid arthritis, dose escalation is ongoing, and patients are currently being enrolled in the 30-microgram dose cohort. The 10- and 20-microgram dose cohorts are complete with no dose-limiting toxicities observed. In the second quarter of 2026, the Company p…

Results of Operations and Financial Condition. As of December 31, 2025, Cullinan Therapeutics, Inc.'s (the "Company's") unaudited cash, cash equivalents, short- and long-term investments, and interest receivable were $439.0 million. Consistent with prior guidance, the Company expects its cash resources to provide runway into 2029 based on its current operating plan. The Company has not yet completed its quarter-end financial close process for the quarter ended December 31, 2025. The Company's…

Termination of a Material Definitive Agreement. On November 18, 2025, in connection with its decision not to pursue further development of CLN-617, Cullinan Amber Corp. (the "Company"), a subsidiary of Cullinan Therapeutics, Inc. notified Massachusetts Institute of Technology ("MIT") of its decision to terminate the Exclusive Patent License Agreement, dated December 20, 2019 between the Company and MIT, as amended from time to time (the "License Agreement"), effective as of February 18, 2026.…

and Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act") or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Other Events. As of September 30, 2025, the Company's cash, cash equivalents, short- and long-term investments, and interest receivable were $475.5 million. The Company expects its cash resources to provide runway into 2029 under its new operating plan. Forward Looking Statements This Current Report on Form 8-K contains forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995. Any statements in this Current Report on Form 8-K that are not hist…

and Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act") or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Director — Anne-Marie Martin, Ph.D.: Dr. Anne-Marie Martin resigned as a director and from the Nominating Committee.

Entry into a Material Definitive Agreement. On June 4, 2025, Cullinan Therapeutics, Inc. (the “Company”) and Chongqing Genrix Biopharmaceutical Co., Ltd. (“Genrix”) entered into a License Agreement (the “License Agreement”), pursuant to which Genrix granted to the Company a global (ex-greater China), exclusive license to develop and commercialize velinotamig, a BCMAxCD3 bispecific T cell engager, in all fields of use. Under the terms of the License Agreement, the Company is obligated to pay G…

and Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act") or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

and Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act") or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Other Events. The REZILIENT1 trial, a Phase 1/2 clinical trial of zipalertinib monotherapy in patients with non-small cell lung cancer harboring the epidermal growth exon 20 insertion mutations who have received prior therapy, met its primary endpoint of overall response rate. The safety profile was generally consistent with previous data presentations. These results are based on the Phase 2b part of this study. The full results from the REZILIENT1 trial will be submitted for presentation at…

and Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act") or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Other Events. On October 16, 2024, the Company announced that the FDA had cleared the Company’s IND application for CLN-978 in SLE. With the IND clearance, the Company may proceed with its global Phase 1 clinical trial in the U.S. to assess CLN-978 in patients with moderate to severe SLE. The trial will enroll patients with a systemic lupus erythematosus disease activity index score of eight or greater and who have had an inadequate response to at least two treatments, including one immunosup…

and Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act") or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Class I director and Audit Committee member — David Meek: The company appointed a new director with extensive experience in the biotechnology and pharmaceutical industries.

and Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Chief Financial Officer — Mary Kay Fenton: The company hired a new Chief Financial Officer.

Entry into a Material Definitive Agreement. Stock Purchase Agreement On April 15, 2024, Cullinan Therapeutics, Inc. (formerly known as Cullinan Oncology, Inc.) (the “ Company ”) entered into a Stock Purchase Agreement (the “ Purchase Agreement ”) for a private placement (the “ Private Placement ”) with certain institutional accredited investors named therein (each, a “ Purchaser ” and collectively, the “ Purchasers ”). Pursuant to the Purchase Agreement, the Company agreed to sell to the Purc…

Other Events. On April 16, 2024, the Company announced its strategic expansion into autoimmune diseases, including the development plan of CLN-978, and the initial clinical observations from CLN-978 in its Phase 1 clinical trial in patients with B-NHL and its Name Change. The Company plans to submit an investigational new drug application to study CLN-978 in patients with systemic lupus erythematosus in the third quarter of 2024. The Company has discontinued enrollment in its B-NHL study to f…