GSK Agrees to Acquire 35Pharma for $950 Million to Boost Pulmonary Hypertension Pipeline

Treatments are limited and outcomes are poor, with around 50% survival at five years. That backdrop explains the market growth outlook: by 2032, PH therapies are forecast to reach $18 billion, with activin signalling inhibitors expected to account for 50% of that. HS235 slots directly into this trend.

Strategic fit: strengthening GSK’s RI&I pipeline

GSK flags HS235 as a strong fit for its Respiratory, Immunology and Inflammation (RI&I) portfolio, highlighting potential protective effects on vascular function and fat-derived markers of metabolism and inflammation. The company also sees scope to extend this biology across chronic diseases that affect the lung, liver and kidney.

In other words, this is not just about one PH asset. It is about an emerging platform of products with protective metabolic and vascular benefits, which could be leveraged across multiple organ systems if clinical data cooperates.

Deal terms, approvals and what’s disclosed

The transaction is straightforward: GSK will acquire 100% of 35Pharma for $950 million in cash at closing. No earn-outs, milestones, or royalty structures are mentioned – not disclosed. The deal is subject to customary conditions, including regulatory clearance under the Hart-Scott-Rodino Act in the US, the Competition Act in Canada, and a filing under the Investment Canada Act.

Timelines to close are not disclosed. Specific development milestones, trial designs, and expected readouts are also not disclosed beyond the note that PAH and PH-HFpEF studies will start imminently.

Key numbers at a glance

Purchase price	$950 million (cash at closing)
Lead asset	HS235 (activin signalling inhibitor)
Clinical stage	Completed phase I in healthy volunteers; PAH and PH-HFpEF studies to start imminently
Global PH prevalence	Approximately 82 million people
US addressable PAH + PH-HFpEF population	Approximately 100,000 people
5-year survival in PH	Around 50%
PH market forecast (2032)	$18 billion; activin inhibitors expected to be ~50%
Regulatory conditions	HSR (US), Competition Act (Canada), Investment Canada Act filing

Management’s take

GSK’s Chief Scientific Officer, Tony Wood, calls HS235 a potential best-in-class medicine with a differentiated profile to reduce bleeding risk and deliver metabolic benefits relevant to PH. He also points to broader opportunities across RI&I to address metabolic, inflammatory, vascular and fibrotic drivers of chronic disease.

35Pharma’s CEO, Ilia Tikhomirov, frames the deal within a shift in PH understanding, suggesting the disease could be reversed, and endorses GSK as a capable owner to advance HS235.

Investor view: what looks good and what to watch

Positives

• Strong strategic fit: HS235 complements GSK’s RI&I ambitions with a vascular-metabolic angle.
• Design advantage: enhanced selectivity aims to reduce bleeding risk – a practical, patient-relevant differentiator.
• Large, growing market: PH therapies forecast at $18 billion by 2032, with activin inhibitors expected to take 50% share.
• Pipeline breadth potential: GSK highlights scope across lung, liver and kidney diseases, not just PH.

Watch-outs

• Early stage: HS235 has completed phase I in healthy volunteers; efficacy and safety in PH patients remain to be proven.
• Regulatory path: deal closing is subject to US and Canadian approvals, and clinical timelines are not disclosed.
• Data depth: metabolic benefits are supported by early clinical signals; confirmatory patient data will be key.
• Financial detail: beyond the $950 million cash price, there is no disclosure on earnings impact or development costs.

Why this matters for GSK shareholders

This is a pipeline-building acquisition in a high-need, high-value category. If HS235’s bleeding risk profile and metabolic benefits are borne out in patients, it could underpin a meaningful position in PH where activin inhibitors are expected to dominate. The flip side is development risk: we are pre-proof-of-concept in the target populations.

In short, GSK is paying up for optionality in a biology it knows well within RI&I. The near term is about execution – starting studies promptly, generating clean safety and efficacy data, and charting a path to pivotal trials.

What to watch next

• Start of patient studies in PAH and PH-HFpEF – the company says these will begin imminently.
• Any initial safety and biomarker updates that speak to bleeding risk and metabolic effects – not disclosed yet.
• Regulatory clearances for closing under HSR, the Competition Act and the Investment Canada Act.
• Clarity on development plans within GSK’s broader RI&I strategy, including potential indications beyond PH – not disclosed.

Caution: GSK includes the usual forward-looking statement reminder. As ever with clinical-stage assets, actual outcomes may differ materially from projections.