Registrational Trial for Bexmarilimab in Frontline HR-MDS to Initiate

Following a positive and productive meeting with the US FDA, a registrational phase 2/3 study for bexmarilimab in treatment-naïve patients with higher-risk myelodysplastic syndromes (HR-MDS) will begin.¹ This decision marks a direct path toward accelerated approval, reflecting the FDA's endorsement of the drug's potential in an area of significant unmet clinical need.

The FDA's guidance is a critical milestone, particularly its acceptance of a primary endpoint based on the most recent International Working Group (IWG) 2023 criteria for complete response (CR) and CR equivalent. This updated standard is considered more comprehensive and patient-centric than previous versions. The trial will also include overall survival (OS) as a co-primary efficacy end point, a crucial measure in a disease with a poor prognosis. The study's design will incorporate a dose optimization run-in period before transitioning into the registrational stage, ensuring a robust and well-defined treatment regimen.

“We are extremely encouraged by the collaborative and highly productive dialogue with the FDA, which provided a clear and actionable path for the clinical development of bexmarilimab in frontline HR-MDS, an area of profound unmet medical need,” said Juho Jalkanen, MD, CEO of Faron Pharmaceuticals, in a press release.

Myelodysplastic syndromes are a group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis and a high risk of progression to acute myeloid leukemia (AML). HR-MDS, in particular, carries a poor prognosis, with current treatment options offering limited efficacy and durability.

The BEXMAB study (NCT05428969), an ongoing phase 1/2 trial of bexmarilimab, has already shown promising signals, particularly in patients with relapsed/refractory MDS who have failed hypomethylating agents (HMAs). Updated data released earlier this month showed an increased CR rate in patients with frontline or treatment-naive HR-MDS.² Further, the CR rate increased to 43% (n = 9/21) according to investigator-assessed response per IWG 2006 criteria compared with the original 28% from an earlier data cut.

About the BEXMAB Study

BEXMAB is a phase 1/2 study evaluating bexmarilimab combined with standard-of-care therapy in patients with MDS, chronic myelomonocytic leukemia, or acute myeloid leukemia.³ The study enrolled patients across 10 sites in the US, Finland, and the United Kingdom, and patients received bexmarilimab with azacitidine and/or venetoclax (Venclexta).

The study’s primary end point was incidence of dose-limiting toxicities, incidence of adverse events, CR rate, overall response rate, CR with incomplete blood recovery, and measurable residual disease status. Secondary end points included progression-free survival, overall survival, anti-bexmarilimab antibody positivity, and serum concentrations of bexmarilimab.

To be eligible for study enrollment, patients were required to have adequate leukocyte counts, renal function, and hepatic function. Those with an ECOG status greater than 2 or an active autoimmune disorder or who had received an allogeneic transplantation within 6 months were not eligible for participation.

About Bexmarilimab

Bexmarilimab is an investigational immunotherapy that aims to overcome resistance to existing treatments and optimize clinical outcomes.¹ This is done by targeting myeloid cell function and igniting the immune system. binding to Clever-1, an immunosuppressive receptor that is seen on macrophages, leading to tumor growth and metastases. When the Clever-1 receptor is targeted, bexmarilimab changes the tumor microenvironment, reprogramming macrophages from an immunosuppressive to an immunostimulatory state.

In March 2025, the FDA granted the agent orphan drug designation for the treatment of patients with MDS.⁴

REFERENCES:

1. Inside Information: Faron to advance bexmarilimab into a registrational Phase 2/3 study in treatment-naïve (frontline) HR-MDS after positive meeting with the FDA. News release. Faron Pharmaceuticals. August 18, 2025. Accessed August 19, 2025. https://tinyurl.com/2s393uuh

2. Inside Information: Faron to present updated BEXMAB data in frontline HR-MDS to FDA; complete remission rate substantially increased to 43%. News release. Faron Pharmaceuticals. August 6, 2025. Accessed August 19, 2025. https://tinyurl.com/mt6usmph

3. A Study to Assess Safety, Tolerability and Preliminary Efficacy of Bexmarilimab in Combination With Standard of Care in Patients With Hematological Malignancies (BEXMAB). ClinicalTrials.gov. Updated May 31, 2025. Accessed August 7, 2025. https://clinicaltrials.gov/study/NCT05428969

4. Inside information: FDA grants orphan drug designation for bexmarilimab in MDS. News release. Faron Pharmaceuticals. March 3, 2025. Accessed August 19, 2025. https://tinyurl.com/4356vnnc