GSK in Agreement to Acquire 35Pharma for Nearly $1B

On February 25, 2026, GSK announced an agreement to acquire 35Pharma Inc. for $950 million, signaling a strategic expansion into the specialized cardiopulmonary market, specifically targeting conditions with high mortality and limited therapeutic options.¹ The focus of this transaction is HS235, a protein-based therapeutic designed as an activin signaling inhibitor. This molecule targets the activin receptor signaling pathway, a validated therapeutic target for pulmonary hypertension (PH), a condition affecting approximately 82 million people globally with a five-year survival rate of only 50%. The global market for these therapies is projected to reach $18 billion by 2032, with activin signaling inhibitors expected to represent half of that value.

How Does the Design of HS235 Address Existing Clinical and Manufacturing Challenges?

A primary challenge in developing treatments for PH is managing the risk of adverse events, such as bleeding and telangiectasia, often caused by off-target binding to bone morphogenetic protein 9 (BMP9) and bone morphogenetic protein 10 (BMP10).¹ HS235 is engineered with enhanced selectivity to reduce binding to BMP9 and BMP10, which is particularly relevant for the significant patient population requiring concurrent anticoagulant or antiplatelet therapies. By improving the safety profile through molecular engineering, developers can potentially address a broader patient base while mitigating risks associated with existing ligands. Tony Wood, chief scientific officer, GSK, said in a press release,¹ “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.”

What Are the Developmental Prospects for HS235 Beyond Vascular Function?

The clinical development of HS235 has progressed through phase I trials in healthy volunteers, with upcoming studies planned for pulmonary arterial hypertension and PH due to heart failure with preserved ejection fraction.¹ These trials will take place in specialized academic centers in which PH programs are integrated into larger respiratory and critical care units. Beyond its vascular benefits, the underlying mechanism of the drug offers unique metabolic advantages, including fat-selective weight loss and improved insulin sensitivity. These secondary benefits are significant for the PH population, in which obesity and insulin resistance are prevalent comorbidities. Ilia Tikhomirov, CEO, 35Pharma, said in a press release,¹ “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.” The integration of this asset into the respiratory, immunology, and inflammation portfolio provides scalable opportunities to treat chronic diseases affecting the lung, liver, and kidney by addressing metabolic and inflammatory drivers. Completion of the acquisition is subject to standard regulatory clearances in the US and Canada.

How Else Is GSK Advancing Its Drug Portfolio?

GSK recently announced the results of a study involving over 2.5 million adults that indicated Arexvy, a recombinant respiratory syncytial virus (RSV) vaccine, was 75.6% effective in preventing related hospitalizations involving severe COPD and asthma flare-ups.² The data showed a 63.1% reduction in major adverse cardiovascular events during hospitalization. Significant reductions in severe flare-ups were also observed for patients with chronic obstructive pulmonary disease and asthma. On these findings. Christian Felter, global medical lead, RSV, GSK, said in a press release,² “These data underscore the value of our RSV vaccine in its observed association with helping to prevent RSV-related hospitalization and reducing the risk of acute events of certain chronic conditions associated with this potentially serious disease.” Ultimately, integrating these advancements into a single portfolio allows for broader clinical coverage across the vascular, metabolic, and inflammatory drivers that define modern pharmaceutical strategy.

References

1. GSK. GSK enters agreement to acquire 35Pharma Inc. London (UK): GSK plc; 2026. Available at: https://www.gsk.com/en-gb/media/press-releases/gsk-enters-agreement-to-acquire-35pharma-inc/. Accessed February 25, 2026.
2. GSK. GSK’s Arexvy associated with reductions in certain RSV-related risks including heart attack, stroke and severe flare-ups of COPD and asthma, real world study shows. London (UK): GSK plc; 2026. Available at: https://www.gsk.com/en-gb/media/press-releases/gsk-s-arexvy-associated-with-reductions-in-certain-rsv-related-risks-including-heart-attack-stroke-and-severe-flare-ups-of-copd-and-asthma-real-world-study-shows/. Accessed February 25, 2026.