GSK has agreed to acquire Canadian drugmaker 35Pharma for up to US$950m, gaining an experimental treatment for pulmonary arterial hypertension.
The drug, HS235, has completed Phase 1 testing in healthy volunteers. GSK said it plans to move the treatment into studies targeting pulmonary arterial hypertension or another form of pulmonary hypertension linked to heart failure.
Pulmonary arterial hypertension is a condition in which high blood pressure develops in the arteries connecting the heart and lungs, placing strain on the heart.
HS235 works by blocking activin signalling, a biological pathway linked to abnormal cell growth that can thicken blood vessel walls and restrict blood flow.
This class of medicines has already shown commercial potential. Merck won approval in 2024 for Winrevair, another activin signalling inhibitor used to treat pulmonary arterial hypertension. The drug generated more than US$1.4bn in sales last year, and Merck is seeking to expand its use.
GSK said HS235 could also have additional cardiovascular and metabolic benefits and may carry a lower risk of bleeding, which is a limitation of some current pulmonary hypertension treatments.
The acquisition follows a broader push by GSK’s new chief executive officer Luke Miels to strengthen the company’s drug development pipeline after taking over from Emma Walmsley earlier this year.
The 35Pharma deal comes shortly after GSK announced a US$2.2bn takeover of allergy drug developer Rapt Therapeutics.
Miels is seeking to address investor concerns about the company’s performance during Walmsley’s tenure. GSK’s outlook has improved since last year, helped by regulatory approvals for medicines treating multiple myeloma, a blood cancer, and asthma.
The company is also optimistic about an experimental hepatitis treatment that recently succeeded in two Phase 3 trials.
GSK’s share price, which was largely unchanged between February 2021 and February 2025, has risen strongly over the past year. The stock climbed about 56 per cent after the company released strong earnings results on 4 February.
Speaking to investors that day, Miels said he sees a clear route to improving shareholder value. A key part of that strategy is expanding the company’s pipeline through targeted acquisitions.
“To accelerate the pipeline we need to have more scientific courage and be more agile to capitalize on opportunities when we see them,” Miels said.
GSK cited industry forecasts suggesting the pulmonary hypertension market could reach US$18bn by 2032. About half of that revenue is expected to come from activin signalling inhibitors such as HS235.
The company also suggested the drug could have additional effects, including possible weight loss while maintaining lean body mass and improvements in insulin sensitivity.
