British pharmaceutical company GSK has agreed to acquire Aiolos Bio, a clinical-stage biopharmaceutical company focused on respiratory and inflammatory conditions, for $1.4bn.

Under the terms of the agreement, the British drugmaker will make a $1bn upfront payment and up to $400m in certain success-based regulatory milestone payments.

The transaction is subject to customary conditions, including relevant regulatory approvals under the Hart-Scott-Rodino Act in the US.

Through the acquisition, GSK will get access to Aiolos’ potential long-acting anti-thymic stromal lymphopoietin (TSLP) monoclonal antibody, AIO-001.

AIO-001 works by binding to the human thymic stromal lymphopoietin (TSLP) ligand to inhibit TSLP signalling, which plays a central role in driving inflammation, including asthma.

The drug is ready to enter Phase 2 clinical development for the treatment of adults with asthma, with the potential for additional indications, including chronic rhinosinusitis with nasal polyps.

Aiolos secured an exclusive license to AIO-001 outside of Greater China, from Chinese pharmaceutical company Jiangsu Hengrui Pharmaceuticals.

GSK chief scientific officer Tony Wood said: “We have a proud heritage and deep development expertise in respiratory medicines, especially addressing diseases driven by IL-5 with high levels of eosinophils or high T2 inflammation.

“Adding AIO-001, a potentially best-in-class medicine targeting the TSLP pathway, could expand the reach of our current respiratory biologics portfolio, including to the 40% of severe asthma patients with low T2 inflammation where treatment options are still needed.”

TSLP is a clinically validated target in the treatment of asthma, regardless of biomarker status, and is a key driver of the inflammatory response in major allergic and inflammatory diseases.

In the early studies, AIO-001 initially showed safety, tolerability, pharmacokinetics, and biological activity in healthy volunteers and asthma patients.

Based on its enhanced potency and half-life extension technology, the drug can be administered every six months and could redefine the standard of care.

With AIO-001, GSK could provide a biologic treatment option to millions of patients living with asthma regardless of biomarker status, including those with low T2 inflammation.

Aiolos Bio CEO Khurem Farooq said: “We believe that this transaction speaks to the high potential of our long-acting anti-TSLP monoclonal antibody, AIO-001.

“By uniting with GSK, a leader with decades of experience developing respiratory therapies and a shared commitment to improving patient lives, we’re confident that we can rapidly advance this therapy in the hopes of significantly reducing the treatment burden for patients.”