GSK to buy liver disease drug from Boston Pharmaceuticals for up to $2 billion

GSK will buy efimosfermin, a liver disease drug in late-stage trials, for up to $2 billion from U.S. biotechnology firm Boston Pharmaceuticals, the British drugmaker said on Wednesday.

Efimosfermin, a monthly subcutaneous injection, is a phase III ready medicine expected to be launched in 2029 to treat steatotic liver disease (SLD). It is also currently in clinical development for the treatment of MASH, a form of liver disease, characterised by inflammation and damage caused by build up of fat.

GSK will pay up to $2 billion cash, comprising an upfront payment of $1.2 billion and up to $800 million in success-based milestone payments.


Under the terms of the agreement, GSK will buy BP Asset IX, Inc., a subsidiary of Boston Pharmaceuticals, to access efimosfermin.

GSK is further planning to develop the drug for potential treatment of alcohol-related liver disease (ALD).

SLD affects about 5% of the global population, ALD affects about 26 million patients around the world.

GSK has been actively advancing therapies for liver disease. In a presentation in December 2024, it had said GSK'990, an experimental drug in phase I trials had shown it can reduce markers indicating liver damage, suggesting potential to slow or halt disease progression.

GSK said on Wednesday it will also pay milestone payments and tiered royalties to Novartis Pharma for efimosfermin, without giving details.