GSK is set to acquire efimosfermin alfa from Boston Pharmaceuticals in a deal valued at up to $2bn, aimed at addressing the significant unmet medical needs associated with steatotic liver disease (SLD).
The acquisition involves an upfront payment of $1.2bn, with potential additional payments reaching $800m based on success milestones. It is expected to strengthen GSK’s pipeline in hepatology by focusing on both viral and steatotic drivers of fibrotic liver diseases.
Boston Pharmaceuticals board chair Elias Zerhouni said: “We are delighted that GSK, a global leader, recognised efimosfermin’s potential to address a growing global public health concern and unmet medical need.
“Together, we look forward to efimosfermin’s ongoing journey to become a best-in-class treatment for patients with SLD.”
Efimosfermin, a fibroblast growth factor 21 (FGF21) analogue, is in Phase III clinical trials for metabolic dysfunction-associated steatohepatitis (MASH) and alcohol-related liver disease (ALD).
The drug candidate aims to target metabolic and fibrotic liver diseases, showing potential for treating advanced SLD stages. GSK’s acquisition aligns with its research focus on immune system-related science and fibrosis.
The company aims to develop improved precision interventions for reversing disease progression, leveraging its genetic research and phenotyping insights.
Steatotic liver disease is prevalent, affecting about 5% of the global population and presenting limited treatment options. MASH and ALD are primary causes of liver transplants in the US, contributing to significant healthcare costs.
Efimosfermin’s role in potentially reducing liver fibrosis could lead to substantial savings for the US healthcare system by decreasing end-stage liver disease expenses.
Phase II trial results for efimosfermin demonstrated significant fibrosis reversal and prevention of progression in patients with moderate-to-advanced MASH.
The findings suggest benefits that could extend beyond current therapeutic approaches, including improved triglyceride levels and glycaemic control for patients with cardiometabolic conditions.
Efimosfermin’s properties, such as low immunogenicity and extended half-life, support a monthly dosing regimen enhancing patient convenience.
GSK chief scientific officer Tony Wood said: “The FGF21 class has shown some of the most exciting data in MASH including first-in-disease evidence of cirrhosis reversal, and efimosfermin has the potential to define a new standard-of-care with its monthly dosing and tolerability profile.
“Efimosfermin will significantly expand our hepatology pipeline and provide us the opportunity to develop a new potential best-in-class medicine with first launch expected in 2029. It complements GSK‘990, also in development for ALD and MASH, offering GSK options to develop both monotherapy and potential combinations to improve patient outcomes.”
The transaction requires regulatory approval under the Hart-Scott-Rodino Act in the US.
GSK will acquire BP Asset IX, a Boston Pharmaceuticals subsidiary, securing rights to efimosfermin and agreeing to tiered royalties owed to Novartis Pharma.
Evercore Partners International is serving as GSK’s financial adviser for the deal, with legal representation by Cleary Gottlieb Steen & Hamilton. Boston Pharmaceuticals is advised by Centerview Partners, with legal counsel from Sullivan & Cromwell.
