• BOS-580 treatment over 12 weeks led to significant changes in the circulating lipidome, reduced MASEF scores and improved MASEF risk classification in patients with phenotypic MASH

CAMBRIDGE, MA, USA I June 05, 2024 I Boston Pharmaceuticals, a clinical-stage biopharmaceutical company developing differentiated molecules addressing serious liver diseases, today announced new Phase 2a data demonstrating the positive impact of BOS-580, an investigational, long-acting fibroblast growth factor 21 (FGF21) analogue, on the circulating lipidome and changes in the metabolomics advanced steatohepatitis fibrosis (MASEF) score in patients with phenotypic metabolic dysfunction-associated steatohepatitis (MASH). The data will be presented at the European Association for the Study of the Liver (EASL) Congress 2024, held from June 5-8 in Milan, Italy.

“Our analysis demonstrated that the circulating lipidome in phenotypic MASH patients is distinct compared to that seen in obese but otherwise healthy adults. Treatment of these patients with BOS-580 over 12 weeks substantially improved patient lipid profiles and reduced MASEF scores, a novel composite biomarker to identify at-risk MASH patients,” said Sophie Kornowski, CEO of Boston Pharmaceuticals. “These data continue to highlight BOS-580’s potential as a powerful once-monthly treatment for MASH. They also support the relevance and potential use of diagnostic and predictive biomarkers in MASH for patient assessment and management. We look forward to sharing biopsy results from our ongoing study in patients with stage F2/F3 fibrosis due to MASH later this year.”

Improvements in Circulating Lipidome and MASEF Scores in Phenotypic MASH Treated with BOS-580
Changes observed in the lipidome in MASH patients suggest that dysregulation in lipid metabolism may be fundamental to the disease’s development, contributing to oxidative stress, inflammation and cell death. Understanding the role of lipid metabolism in healthy and disease states has the potential to drive the discovery of potential biomarkers for diagnosis and new therapeutic targets. The MASEF score is a metabolomics-driven score that offers a noninvasive way to identify patients with at-risk MASH who could benefit from medical therapies and intervention, making it a promising diagnostic tool.1

In this analysis, researchers evaluated variations in the comprehensive profile of lipids present in the bloodstream after 12 weeks of treatment with BOS-580 in patients with phenotypic MASH who were enrolled in Part A of a randomized, double-blind, placebo-controlled Phase 2a study (N=102). Results show:

  • BOS-580 treatment led to extensive changes in the circulating lipidome, including decreased levels of saturated fatty acids and triglycerides; notably, these samples also had significantly lower levels of lipotoxic molecules such as diglycerides and ceramides, suggesting that the potential beneficial effects of BOS-580 may be mediated in part by reducing lipotoxic molecules in MASH patients.
  • Eighty-eight percent of patients treated with BOS-580 achieved reductions in their composite MASEF scores, compared to 33% in the placebo group.
  • Treatment with BOS-580 also improved MASEF risk classification by decreasing the number of patients identified to be at-risk for MASH from 20% at baseline to 2% at 12 weeks, compared to an increase from 17% at baseline to 20% at 12 weeks in the placebo group.

Details of Boston Pharmaceuticals’ presentation at EASL are as follows:

Title: BOS-580, a long-acting FGF21 analogue, treatment shows beneficial changes in the circulating lipidome and improves MASEF score in patients with phenotypic metabolic dysfunction-associated steatohepatitis in a Phase 2a randomized, placebo-controlled, 12-week study (Poster Presentation)
Abstract Number: 621
Poster Number: WED-220
Session Date, Time: June 5, 8:30 am CEST
Presenter: Gerard Bain, Boston Pharmaceuticals

For more information about BOS-580 and Boston Pharmaceuticals’ pipeline of highly engineered targeted therapies for patients with serious liver diseases, visit Booth #O1 at EASL Congress 2024.

About Boston Pharmaceuticals
Boston Pharmaceuticals is a clinical stage biopharmaceutical company that leverages an experienced and committed drug development team to advance a portfolio of highly differentiated therapies that may address important unmet medical needs in serious liver diseases, with MASH as the focus of its lead asset. The Company has significant expansion opportunities through its portfolio of promising drug development candidates that were acquired through partnerships with proven, innovative biotechnology and pharmaceutical companies. Boston Pharmaceuticals applies rigorous decision making to advance programs to deliver differentiated medicines to patients in need of new options, while creating value for all parties involved in the journey.

For more information, please visit www.bostonpharmaceuticals.com and follow us on LinkedIn.

About B-Flexion
Boston Pharmaceuticals is a portfolio company of B-Flexion, a private entrepreneurial investment firm that partners with sophisticated capital to deliver exceptional value over the generations, while also contributing positively to society. Chaired by Ernesto Bertarelli and with offices across Europe and the United States, B-Flexion seeds, acquires and builds investment partnerships, principally in the fields of Private Equity, Venture & Growth Capital, Real Assets, Hedge Funds, Credit, and Public Securities. As well as these partnerships, B-Flexion makes principal investments in operating businesses in transformative industries with a focus on Healthcare, Planet, Consumer and Technology.

For more information, please visit www.bflexion.com.


  1. Noureddin M, Truong E, Mayo R, et al. Serum identification of at-risk MASH: The metabolomics-advanced steatohepatitis fibrosis score (MASEF). Hepatology. 2024;79(1):135-148. doi:10.1097/HEP.0000000000000542.

SOURCE: Boston Pharmaceuticals