35Pharma, Inc.

GSK said Wednesday it will acquire a 100% equity stake in Canadian clinical-stage biotech 35Pharma for $950 million in cash, securing rights to the latter's lead asset — an activin signalling inhibitor (ASI) being developed for pulmonary hypertension (PH)."We're delighted to add HS235 to our pipeline, a potential best-in-class medicine with a differentiated profile to reduce risk of bleeding and provide potential metabolic benefits clinically relevant to PH patients," said Tony Wood, chief scientific officer at GSK.The UK pharma, which markets the endothelin receptor antagonist Volibris (ambrisentan) for pulmonary arterial hypertension (PAH) outside the US, anticipates the global PH therapeutics market to reach $18 billion by 2032 — with ASIs likely to capture approximately half of that figure. The current ASI landscape is dominated by Merck & Co.'s Winrevair (sotatercept), the sole drug in its class approved for PAH in the US and EU, which racked up $1.4 billion in revenue last year (see — Spotlight On: Merck & Co.'s fastest selling drugs in 2025).HS235, which complements GSK's respiratory, immunology and inflammation portfolio, has completed early-stage testing in PAH, with studies in PH due to heart failure with preserved ejection fraction slated to begin soon. The molecule is designed for enhanced selectivity in the activin receptor pathway, thereby limiting binding with BMP9/10 ligands linked to bleeding and telangiectasia — a potential advantage for patients with PH on anticoagulants or antiplatelets.Early clinical data also indicated fat-selective weight loss, lean mass preservation and improved insulin sensitivity with HS235, alongside favourable changes in inflammation and adipokine profiles.

GSK said on Wednesday that it is buying 35Pharma for $950 million, picking up the Canadian biotech’s pulmonary hypertension drug program — and potentially dipping its toes into investigating weight loss drugs that avoid muscle loss. At the heart of the deal is a drug called HS235, which has completed studies in healthy subjects and is about to enter clinical trials. The upcoming trials will focus on pulmonary arterial hypertension ( PAH ) and pulmonary hypertension due to heart failure with preserved ejection fraction ( PH-HFpEF ). On its website, 35Pharma describes HS235 as a multispecific “decoy trap” for activin and growth differentiation factors, which can contribute to PH. In this way, it zeroes in on what’s called the activin receptor signaling pathway, and its “enhanced selectivity” could reduce bleeding and broken blood vessels as side effects. These are sometimes seen with current PH therapies, GSK said. One of the most high-profile drugs in PAH is Merck’s Winrevair , which comes with a bleeding risk warning . Another company trying to compete in this space is Gossamer Bio, but the chances of approval for its drug seralutinib look poor following a Phase 3 failure on Monday. GSK has clearly stated it is not looking to enter the crowded race for obesity drugs. But the UK pharma said Wednesday that the underlying mechanism of HS235 has “broad metabolic benefits,” suggesting that it can test the waters with its new purchase. Those benefits include weight loss with preservation of lean mass, as well as improved insulin sensitivity, which GSK notes is an issue among PH patients. While it was not mentioned in the Wednesday announcement, 35Pharma also has an asset called HS370 in preclinical testing for heart failure and obesity. HS235 also completed a Phase 1 trial in overweight and obese patients. In obesity, an increasingly crowded field dominated by Eli Lilly, certain companies — like Regeneron , Scholar Rock and Biohaven — are looking to capture a market segment by studying muscle-sparing weight loss drugs. GSK chief scientific officer Tony Wood said in a press release that 35Pharma offers opportunities within its respiratory, immunology, and inflammation portfolio “to achieve broader coverage across the metabolic, inflammatory, vascular and fibrotic drivers of multiple chronic diseases that affect the lung, liver and kidney.” At his first earnings call in February, GSK’s new CEO Luke Miels said the company will be active in dealmaking to help meet its 2031 sales target and address the upcoming patent cliff in its HIV franchise. Earlier this week, GSK said it is licensing Frontier Biotechnologies’ siRNAs for unnamed immunological diseases. 35Pharma last raised funds in November 2024 through a $53 million Series C led by Frazier Life Sciences.

In a deal worth $950m, GSK has agreed to acquire 35Pharma, a private, clinical-stage biopharmaceutical company based in Canada that specialises in the development of novel protein-based therapeutics. The acquisition includes HS235, a potential best-in-class investigational medicine for pulmonary arterial hypertension (PAH) and pulmonary hypertension due to heart failure with preserved ejection fraction (PH-HFpEF). HS235 has completed phase 1 healthy volunteer clinical trials, with studies due to start in PAH and PH-HFpEF. PH is a progressive, life-shortening disease marked by high blood pressure in the lungs. Early symptoms are breathlessness, fatigue and chest pain leading to heart failure as the disease progresses. It affects approximately 82 million people worldwide across multiple disease forms, yet treatment options remain limited and the five‑year survival rate is only around 50%. By 2032, the global market for PH therapies is forecast to reach $18bn. Tony Wood, Chief Scientific Officer at GSK, said: “Pulmonary hypertension affects millions of people worldwide, yet patients are underserved. We’re delighted to add HS235 to our pipeline, a potential best-in-class medicine with a differentiated profile to reduce risk of bleeding and provide potential metabolic benefits clinically relevant to PH patients. “HS235’s potential protective effects on vascular function, alongside potential benefits on fat-derived markers of metabolism and inflammation, also offer new development opportunities within our RI&I portfolio to achieve broader coverage across the metabolic, inflammatory, vascular and fibrotic drivers of multiple chronic diseases that affect the lung, liver and kidney.” Ilia Tikhomirov, CEO at 35Pharma, said: “In recent years, we witnessed a revolution in our understanding of pulmonary hypertension and how this life-threatening disease could be reversed. “We are pleased to be joining forces with GSK, a leader in respiratory and inflammatory drivers of disease, who shares our vision of HS235’s potential to transform the treatment of this debilitating condition.”