Boston Pharmaceuticals announced positive topline results from its Phase 2 study of efimosfermin alfa (BOS-580), a long-acting FGF21 analogue, in patients with stage F2/F3 fibrosis due to metabolic dysfunction-associated steatohepatitis (MASH). The study demonstrated significant improvements in fibrosis and MASH resolution, along with favorable cardiometabolic benefits.
The Phase 2 randomized, double-blind, placebo-controlled study (N=84) assessed the efficacy and safety of once-monthly subcutaneous injections of efimosfermin 300 mg over 24 weeks. The results, presented at The Liver Meeting of the American Association for the Study of Liver Diseases (AASLD), highlight the potential of efimosfermin as a treatment for MASH.
Key Findings from the Phase 2 Trial
- Fibrosis Improvement: 45.2% of patients treated with efimosfermin achieved at least a 1-stage improvement in fibrosis without worsening of MASH, compared to 20.6% in the placebo group (p=0.038).
- MASH Resolution: 67.7% of efimosfermin-treated patients experienced MASH resolution without worsening of fibrosis, versus 29.4% in the placebo group (p=0.002).
- Cardiometabolic Benefits: The study observed rapid and significant improvements in liver fat reduction and glycemic control, particularly in MASH patients with obesity and type 2 diabetes.
"These new data demonstrate that efimosfermin may rapidly and significantly reduce disease progression in people diagnosed with moderate-to-advanced-stage liver disease, is well-tolerated and offers the convenience of monthly dosing – all factors that are important to this patient population," said Mazen Noureddin, M.D., M.H.Sc., lead investigator and professor of medicine at Houston Methodist Hospital.
Additional Benefits and Future Plans
Participants treated with efimosfermin also showed rapid improvements in fibrosis biomarkers and reductions in non-invasive markers of liver injury and liver fat. The treatment was well-tolerated, with low discontinuation rates due to adverse events and a low incidence of gastrointestinal side effects and injection site reactions.
"These data indicate that efimosfermin may effectively target the three main components of hepatic disease, thereby producing a meaningful impact on fibrosis improvement, which is a critical and often under-treated aspect of managing MASH," stated Margaret Koziel, M.D., Chief Medical Officer at Boston Pharmaceuticals.
Boston Pharmaceuticals is continuing the clinical development program with an open-label extension study to assess the long-term safety and efficacy of efimosfermin. The company anticipates advancing the clinical program to late-stage development in 2025.
