CAMBRIDGE, Mass. — 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 announced positive feedback from the U.S. Food and Drug Administration (FDA) following an End-of-Phase 1 (EOP1) meeting for CLN-049, a FLT3xCD3 T cell engager being evaluated in patients with acute myeloid leukemia (AML).
The EOP1 meeting focused on the planned Phase 2 development strategy for CLN-049. Based on discussions with the FDA, Cullinan will initiate a potentially registrational Phase 2 study of CLN-049 in patients with relapsed/refractory AML in the third quarter of 2026. The study design agreed with the FDA incorporates a short dose-optimization phase with seamless progression to a single-arm cohort at the recommended Phase 2 dose.
“Patients with AML continue to face poor outcomes and have limited treatment options, underscoring the need for new therapeutic approaches,” said Jeffrey Jones, MD, MBA, Chief Medical Officer, Cullinan Therapeutics. “The FDA’s feedback reinforces our confidence in the development strategy for CLN-049 and provides a clear path forward for potential regulatory approval. We look forward to continuing to advance the CLN-049 program and exploring its potential across AML patient populations.”
As presented at the 2025 American Society of Hematology (ASH) Annual Meeting, CLN-049 demonstrated promising clinical activity and a favorable safety profile in patients with relapsed/refractory AML. The Company plans to share an update from the dose escalation portion of this study in Q4 2026.
Following the positive feedback from the FDA, the Company plans to initiate a potentially registrational Phase 2 study in patients with relapsed/refractory AML in Q3 2026. The Company will also initiate a Phase 1/2 study evaluating the combination of CLN-049, venetoclax, and azacitidine in patients with previously untreated AML (NCT07722767).
About CLN-049
CLN-049 is a novel, investigational FLT3xCD3 bispecific T cell engager. CLN-049 is designed to target FLT3-expressing leukemia cells, offering a new immunotherapeutic approach for treating acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). CLN-049 binds to both mutated and non-mutated FLT3, allowing targeted action regardless of FLT3 mutational status, making the investigational treatment widely applicable to a broad population.
CLN-049 is being studied in a Phase 1, open-label, multicenter, first-in-human, multiple ascending dose study evaluating safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and preliminary efficacy of intravenously (IV) administered CLN-049 in patients with relapsed/refractory AML or MDS (NCT05143996) and in a parallel Phase 1, open-label, dose escalation and dose expansion study for the treatment of patients with AML with measurable residual disease (MRD) (EUCT 2023-506572-27-00).
CLN-049 has received Orphan Drug designation and Fast Track designation from the U.S. FDA for the treatment of relapsed/refractory AML.
About Acute Myeloid Leukemia
Acute myeloid leukemia (AML) is a cancer of the blood and bone marrow, and the most common form of acute leukemia in adults.1 It is characterized by the rapid growth of abnormal white blood cells that crowd out healthy cells, leading to infections, fatigue, and bleeding.2 Each year in the U.S., approximately 23,000 people are diagnosed with AML, and about half as many lives are lost to the disease.3 Globally, AML affects an estimated 145,000 people annually, with approximately 130,000 deaths.4
Despite recent advances, outcomes for patients with AML remain poor, particularly for those with relapsed or refractory disease, where five-year survival is 10% or less.5 Patients with high-risk genetic features, such as complex karyotype or TP53 mutations, face especially limited options.6,7 Intensive treatments like chemotherapy and stem cell transplantation may be inaccessible for many older patients due to severe side effects.7 Currently, there are no approved immunotherapies for AML, underscoring the urgent need for novel therapeutic approaches that can improve outcomes for patients and their families facing this life-threatening disease.
About Cullinan Therapeutics
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.
Contacts
Investors
Nick Smith
+1 401.241.3516
[email protected]
Media
Rose Weldon
+1 215.801.7644
[email protected]
References
- American Association for Cancer Research. (2025). Acute Myeloid Leukemia. https://www.aacr.org/patients-caregivers/cancer/acute-myeloid-leukemia/
- Leptidis, J., et al. (2014). Fatal cardiac tamponade as the first manifestation of acute myeloid leukemia. Am J Emerg Med 32(10). https://doi.org/10.1016/j.ajem.2014.02.045
- National Cancer Institute. (2025). Cancer Stat Facts: Leukemia — Acute Myeloid Leukemia (AML). https://seer.cancer.gov/statfacts/html/amyl.html
- Zhou, Y., et al. (2024). Global, regional, and national burden of acute myeloid leukemia, 1990–2021: A systematic analysis for the Global Burden of Disease Study 2021. Biomarker Research, 12(101). https://doi.org/10.1186/s40364-024-00649-y
- Moore, CG., et al. (2025). Treatment of Relapsed/Refractory AML—Novel Treatment Options Including Immunotherapy. Am J Hematol. (100)2. https://doi.org/10.1002/ajh.27584
- Shahzad, M., et al. (2024). What have we learned about TP53-mutated acute myeloid leukemia?. Blood Cancer J. 14(202). https://doi.org/10.1038/s41408-024-01186-5
- Kantarjian, H., et al. (2021). Acute myeloid leukemia: current progress and future directions. Blood Cancer J. 11(2). https://doi.org/10.1038/s41408-021-00425-3