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Highlights

  • GSK to acquire Boston Pharmaceuticals’ lead candidate, efimosfermin, for $1.2 billion upfront, with up to $800 million in milestone payments.
  • Efimosfermin shows strong potential to reverse liver fibrosis in metabolic dysfunction-associated steatohepatitis (MASH), a form of steatotic liver disease (SLD).
  • Acquisition significantly strengthens GSK’s hepatology pipeline with potential for a first launch by 2029.

In a strategic move to bolster its liver disease portfolio, GSK plc (LSE:GSK) has announced the acquisition of efimosfermin alfa, a promising investigational treatment for steatotic liver disease (SLD), from Boston Pharmaceuticals. The deal, valued at $2 billion, includes an upfront payment of $1.2 billion, along with performance-based milestones totaling up to $800 million.

Efimosfermin is a Phase III-ready specialty medicine that has shown compelling efficacy in treating metabolic dysfunction-associated steatohepatitis (MASH), a progressive and serious form of SLD. The drug, a novel fibroblast growth factor 21 (FGF21) analog, is designed for once-monthly subcutaneous dosing and targets liver fibrosis directly. Results from a recent Phase II trial demonstrated that efimosfermin can significantly reverse liver fibrosis in patients with moderate-to-advanced MASH (F2 or F3 stages), with a manageable safety profile.

SLD, including MASH and alcohol-related liver disease (ALD), affects nearly 5% of the global population and remains an area of high unmet medical need due to limited treatment options. Combined, MASH and ALD are leading causes of liver transplants in the United States, posing a significant burden on healthcare systems. Experts estimate that effective antifibrotic therapies like efimosfermin could help the U.S. alone save between $40 to $100 billion in healthcare costs over the next 20 years.

GSK’s acquisition is closely aligned with its R&D strategy focused on immune-driven diseases and precision medicine. By adding efimosfermin to its pipeline, GSK aims to address both steatotic and viral drivers of liver disease. The company also sees potential to combine efimosfermin with GSK’990, its investigational siRNA therapy, to further enhance treatment outcomes in SLD patients.

“Efimosfermin’s unique profile offers the potential for a new standard-of-care in liver fibrosis management,” said GSK in a statement. The drug’s benefits may extend beyond liver health, showing positive effects on triglyceride levels and glycaemic control—key concerns for patients dealing with cardiometabolic co-morbidities often linked to MASH.

Full Phase II data, presented at the American Association for the Study of Liver Diseases (AASLD) Meeting in November 2024.