Over the span of five months, biotechnology startup Aiolos Bio launched, raised initial funding from venture investors and negotiated a $1 billion buyout by GSK.

The acquisition, announced by GSK on Tuesday, marks a rapid return on investment for Aiolos’ blue-chip backers, which included Atlas Venture and Bain Capital Life Sciences. They could receive up to $400 million more if certain regulatory milestones are met.

Based in San Francisco and London, Aiolos was founded last year around an experimental antibody for treating asthma that the company licensed in August from China’s Jiangsu Hengrui Pharmaceuticals. The biologic drug, dubbed AIO-001, shares a target with Amgen and AstraZeneca’s approved medicine Tezspire, but Aiolos claims its version could be given less frequently.

AIO-001’s potential drew substantial venture capital interest and in late October Aiolos completed a $245 million Series A — one of the largest last year. With its GSK deal, the startup has now quadrupled their investment in just 11 weeks.

“By uniting with GSK … we’re confident that we can rapidly advance this therapy in the hopes of significantly reducing the treatment burden for patients,” said Aiolos CEO Khurem Farooq, who was previously head of Gyroscope Therapeutics, an eye drug startup bought by Novartis in 2021.

The buyout of Aiolos is the fourth biotech acquisition this week — activity that coincides with the annual J.P. Morgan Healthcare Conference, which is typically viewed as a forum for M&A negotiations and announcements. Along with GSK, Johnson & Johnson, Merck & Co. and Novartis have unveiled deals. 

“We have a proud heritage and deep development expertise in respiratory medicines,” said GSK’s Chief Scientific Officer Tony Wood, in a statement. “Adding AIO-001, a potentially best-in-class medicine targeting the TSLP pathway, could expand the reach of our current respiratory biologics portfolio.”

TSLP is a protein thought to play a role in driving the inflammation that can cause asthma attacks. Tezspire, approved by the Food and Drug Administration in late 2021, was the first drug of its type. Aiolos says its treatment could be taken as infrequently as twice per year, compared to Tezspire’s once-monthly dosing.

But Aiolos — and soon GSK — will have another competitor in Upstream Bio, a 18-month-old startup that’s well advanced in clinical testing of its own TSLP-targeting drug for asthma. In June, the company raised $200 million in Series B funding.

AIO-001 was developed and advanced though early clinical testing by Jiangsu Hengrui, which retains rights to the drugs in Greater China. GSK would owe milestones and royalties to the company if it completes its purchase of Aiolos.

GSK already sells a number of medicines for asthma, including Nucala, an antibody targeting a protein called IL-5, and the Ellipta line of inhalers. It has recently come under scrutiny for discontinuing its branded Flovent inhaler in favor of an authorized generic that might not be as widely covered by insurance.