GSK PLC (LSE:GSK, NYSE:GSK) has agreed to acquire Canadian biotech 35Pharma for $950 million in cash, securing a clinical-stage drug for pulmonary hypertension that its new owner believes can improve on the safety profile of existing therapies in a market forecast to reach $18 billion by 2032.
The asset at the centre of the deal is HS235, an activin signalling inhibitor that has completed phase I healthy volunteer trials and is preparing to enter studies in two forms of the disease: pulmonary arterial hypertension and pulmonary hypertension due to heart failure with preserved ejection fraction.
Activin signalling inhibitors are expected to account for half of all PH therapy revenues within six years, making the class one of the more strategically contested areas of respiratory medicine.
What makes HS235 different
The drug's design addresses a problem that has complicated existing treatments in the same class.
Current activin inhibitors bind to BMP9 and BMP10, proteins associated with bleeding and broken blood vessels, side effects that are particularly problematic given that a significant proportion of PH patients already take anticoagulants.
HS235 is engineered with enhanced selectivity to reduce that binding, potentially making it safer to use in the patients most in need of treatment.
There is a secondary angle that GSK's chief scientific officer Tony Wood was careful to highlight.
Early clinical data suggest HS235 produces metabolic effects, including fat-selective weight loss, preservation of lean muscle mass and improved insulin sensitivity.
Given the high prevalence of obesity and insulin resistance in the PH population, those properties could expand the drug's clinical and commercial reach beyond its core indication.
The strategic fit
PH is a progressive, life-shortening condition affecting around 82 million people worldwide, with a five-year survival rate of roughly 50%. Despite that scale, treatment options remain limited, and the US addressable population for the two indications HS235 is targeting is approximately 100,000 patients.
For GSK, the acquisition slots into its respiratory, immunology and inflammation portfolio and extends a broader push into diseases with metabolic, vascular and fibrotic drivers.
Wood described HS235 as offering development opportunities across conditions affecting the lung, liver and kidney, suggesting GSK sees the drug's mechanism as a platform rather than a single indication.
The deal is subject to regulatory clearance in the US and Canada.