CAMBRIDGE, Mass., July 28, 2026
Cullinan Therapeutics announced positive feedback from the U.S. Food and Drug Administration (FDA) following its End-of-Phase 1 (EOP1) meeting for CLN-049, the company’s investigational FLT3xCD3 T cell engager being developed for acute myeloid leukemia (AML). Based on discussions with the FDA, the company will initiate a potentially registrational Phase 2 clinical trial in patients with relapsed or refractory AML during the third quarter of 2026. The agreed study design includes a short dose-optimization phase followed by a seamless transition into a single-arm Phase 2 cohort using the recommended Phase 2 dose. The regulatory feedback provides a clear development pathway that could support a future regulatory approval if the study demonstrates favorable efficacy and safety.
Clinical Data Supports Continued Development of CLN-049
The advancement of CLN-049 is supported by encouraging Phase 1 clinical results previously presented at the 2025 American Society of Hematology (ASH) Annual Meeting. In patients with relapsed/refractory AML, the investigational therapy demonstrated promising clinical activity together with a favorable safety profile, reinforcing its potential as a novel immunotherapy for a disease with significant unmet medical need. Cullinan Therapeutics plans to provide an additional update from the ongoing dose-escalation portion of the Phase 1 study during Q4 2026. Chief Medical Officer Dr. Jeffrey Jones stated that the FDA’s positive feedback strengthens confidence in the development strategy and supports continued efforts to bring a new therapeutic option to patients with limited treatment choices.
Bispecific T Cell Engager Targets Broad AML Population
CLN-049 is a novel investigational bispecific antibody engineered to bind both FLT3 on leukemia cells and CD3 on T cells, enabling the immune system to selectively attack FLT3-expressing cancer cells. Unlike therapies limited to specific genetic mutations, CLN-049 is designed to target both mutated and non-mutated FLT3, potentially making it suitable for a broader population of patients with AML and myelodysplastic syndrome (MDS). In addition to the registrational Phase 2 trial in relapsed or refractory AML, Cullinan Therapeutics also plans to launch a Phase 1/2 combination study evaluating CLN-049 alongside venetoclax and azacitidine in patients with previously untreated AML, expanding the program into earlier treatment settings.
Advertisement
Program Addresses Significant Unmet Need in AML
Acute myeloid leukemia remains one of the most aggressive blood cancers, with approximately 23,000 new cases diagnosed annually in the United States and poor long-term outcomes, particularly among patients with relapsed or refractory disease, where five-year survival rates remain at or below 10%. Older patients and those with high-risk genetic abnormalities often have limited treatment options because intensive chemotherapy and stem cell transplantation may not be suitable. Currently, no immunotherapies are approved specifically for AML, highlighting the importance of innovative approaches such as CLN-049. The investigational therapy has already received both FDA Fast Track Designation and Orphan Drug Designation for relapsed or refractory AML, supporting its accelerated development as Cullinan Therapeutics advances its mission to develop first- or best-in-class T cell engager therapies for patients with cancer and autoimmune diseases.
Source: Cullinan Therapeutics, press release
