Bexmarilimab Shows Promise in Tough-to-Treat HR MDS; Phase 3 Planned
Bexmarilimab and azacitidine showed continued tolerability and a high overall response rate in relapsed/refractory higher-risk myelodysplastic syndromes in a phase 2 study.
Primary myelofibrosis cells in blood flow: © LASZLO - stock.adobe.com
Topline results from the phase 2 BEXMAB study (NCT05428969) investigating bexmarilimab (FP-1305), an investigational immunotherapy, and azacitidine showed continued tolerability and a high overall response rate (ORR) in patients with relapsed/refractory (R/R) higher-risk myelodysplastic syndromes (HR MDS).1
Full data from the trial have been submitted to the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting. Additionally, a phase 3 trial evaluating the combination is planned, pending feedback from an FDA end-of-phase 2 meeting.
“This is one of the strongest data set ever seen in an all-comer population of treatment resistant HR MDS”, says Juho Jalkanen, MD, chief executive officer of Faron Pharmaceuticals, in a press release. “There is a significant unmet need in the treatment of HR MDS, as drug development in HR MDS and macrophage reprogramming has proven to be extremely challenging, with a lot of previous failures. What really makes bexmarilimab stand out in this field is its good safety profile combined with very high efficacy especially in last line HR MDS. This gives us conviction that bexmarilimab is the long-awaited drug to overcome treatment resistance.”
In March 2025, the FDA granted bexmarilimab orphan drug designation for this intent-to-treat population.2
About the BEXMAB Study
Bexmarilimab is an anti-Clever1 monoclonal antibody that has the potential to provide permanent immune stimulation by targeting myeloid function.3 Data from the dose-escalation and dose-optimization portions of BEXMAB were published in Blood in November 2024 and showed an ORR Of 79% (n = 11), including 1 complete response (CR), 7 marrow CRs, 1 partial response, and 2 hematological improvements.4 Additionally, 2 responses of stable disease and 1 of progressive disease were observed, and 2 patients proceeded to allogeneic stem cell transplantation. The median overall survival estimate among the 14 patients enrolled was 13.4 months.
Regarding safety, a total of 113 treatment-emergent adverse events (AEs) were reported with 74 (65%) being grade 1 to 2. Serious AEs were reported in 7 patients, with febrile neutropenia as the most common. Four AEs in 3 patients were reported and considered to be related to bexmarilimab, which included fever, infusion-related reaction, intermittent nausea, and peripheral edema. All bexmarilimab-related reactions were grade 1.
