CAMBRIDGE, Mass. — Cullinan Therapeutics, Inc. (Nasdaq: CGEM), a clinical-stage biopharmaceutical company accelerating potential first- or best-in-class, high-impact therapies in autoimmune diseases and cancer, today announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation to CLN-049, a novel, investigational FLT3xCD3 T cell engager, for the treatment of relapsed/refractory (R/R) acute myeloid leukemia (AML).
“FDA Orphan Drug Designation for CLN-049 emphasizes both the urgent need for new therapies for people living with relapsed or refractory acute myeloid leukemia – including patients with TP53-mutated AML who currently face a particularly poor prognosis – and the potential of this FLT3-directed T cell engager to expand treatment options across the broadest population of AML patients,” said Jeffrey Jones, MD, MBA, Chief Medical Officer, Cullinan Therapeutics. “Coupled with promising results from our ongoing Phase 1 program, this designation by the FDA reinforces a shared goal to rapidly advance novel therapies for patients living with AML.”
About Orphan Drug Designation
The U.S. FDA’s Orphan Drug Designation provides orphan status to drugs and biologics intended to prevent, diagnose, or treat rare diseases or conditions that affect fewer than 200,000 people in the United States. Orphan Drug Designation qualifies sponsors for certain development incentives, including tax credits for qualified clinical trials, exemption from certain FDA user fees, and the potential for seven years of market exclusivity in the United States following marketing approval.
About CLN-049
CLN-049 is a novel, investigational FLT3xCD3 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, enabling 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 (PD), 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 Fast Track designation from the U.S. Food and Drug Administration 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.1,2 It is characterized by the rapid growth of abnormal white blood cells that crowd out healthy cells, leading to infections, fatigue, and bleeding.3 Each year in the U.S., approximately 22,000 people are diagnosed with AML, and about half as many lives are lost to the disease.4 Globally, AML affects an estimated 144,000 people annually, with approximately 130,000 deaths.5
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.4,6 Patients with high-risk genetic features, such as complex karyotype or TP53 mutations, face especially limited options.7,8 Intensive treatments like chemotherapy and stem cell transplantation may be inaccessible for many older patients due to severe side effects.8 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; “Cullinan”) is a biopharmaceutical company developing potential first- or best-in-class, high-impact therapies 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.
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References
- American Association for Cancer Research. (2025). Acute Myeloid Leukemia. https://www.aacr.org/patients-caregivers/cancer/acute-myeloid-leukemia/
- National Cancer Institute. (2025). Acute Myeloid Leukemia Treatment (PDQ®)–Patient Version. https://www.cancer.gov/types/leukemia/patient/adult-aml-treatment-pdq
- 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