GSK to Acquire 35Pharma for $950 Million to Expand Pulmonary Hypertension Portfolio

On February 25, 2026, GSK entered into an agreement to purchase all shares of 35Pharma Inc., a Canadian clinical-stage biopharmaceutical company, for $950 million in cash. The transaction is intended to strengthen GSK’s presence in treatments for pulmonary arterial hypertension and related conditions.

The acquisition will give GSK control over HS235, 35Pharma’s lead investigational medicine. HS235 targets the activin receptor signalling pathway and is currently in early clinical development for pulmonary arterial hypertension and other cardiopulmonary diseases.

HS235 has completed its initial Phase I trials in healthy volunteers. Upcoming studies are planned for patients with pulmonary arterial hypertension and pulmonary hypertension due to heart failure with preserved ejection fraction.

What the numbers show

• $950 million is the agreed cash consideration for the acquisition
• Merck’s Winrevair, a similar drug, generated over $1.4 billion in sales last year
• The global market for pulmonary hypertension therapies is projected to reach $18 billion by 2032

GSK stated that HS235’s mechanism may offer reduced bleeding risk and metabolic benefits, including fat-selective weight loss, preservation of lean mass, and improved insulin sensitivity, compared to existing therapies. The company indicated that HS235 is expected to enter patient studies soon, with potential availability in the early 2030s if development continues as planned.

The acquisition is subject to customary closing conditions. These include regulatory clearances under the Hart-Scott-Rodino Act in the United States, the Competition Act in Canada, and a filing under the Investment Canada Act.

Merck’s Winrevair, another activin signalling inhibitor for pulmonary hypertension, generated over $1.4 billion in sales last year. HS235 is seen as a potential competitor in this class of therapies.

This transaction follows GSK’s earlier acquisition of Rapt Therapeutics for $2.2 billion in 2026, marking the second major acquisition under CEO Luke Miels. GSK’s shares rose modestly after the announcement of the 35Pharma deal.

The company described the acquisition as part of its strategy to expand its Respiratory, Immunology and Inflammation portfolio with scientifically validated mid-stage assets. Activin signalling inhibitors are expected to represent about half of the projected $18 billion global market for pulmonary hypertension therapies by 2032.

* This article is based on publicly available information at the time of writing.