Altavant Sciences has signed a definitive agreement to acquire private drug development firm Onspira Therapeutics.

Specific financial details of the transaction are yet to be divulged by either company. However, Onspira’s shareholders received an upfront payment, eligible for milestone payments and royalties on net sales.

The acquisition, already closed, provides Altavant with rights over OSP-101, a novel inhaled interleukin-1 receptor antagonist (IL-1Ra) to treat bronchiolitis obliterans syndrome (BOS).

The OSP-101 already received orphan drug designation from the US Food and Drug Administration (FDA).

BOS is a progressive inflammatory condition that blocks normal airflow in the lungs.

The non-infectious complication is usually found among people who previously underwent lung transplantation and hematopoietic stem cell transplantation.

BOS can also be caused by autoimmune diseases and exposure to certain chemicals.

Altavant CEO William T Symonds said: “Adding OSP-101 to our pipeline creates significant value for Altavant, while also furthering our mission to develop drugs for patients with very serious and rare lung diseases.

“Although a majority of lung transplant recipients develop this life-threatening condition, there are no treatments approved specifically for BOS and the current therapies have limited efficacy.”

CoOnspira Therapeutics CEO Brian Lortie said: “We have been impressed by the talented and experienced professionals at Altavant, and we are confident that they are the right team to develop OSP-101 for the treatment of post-lung transplant BOS.

“This is an important programme to bring forward for the benefit of lung transplant patients, and we believe Altavant is well-positioned to achieve this goal.”

The Onspira Therapeutics acquisition comes several months after Altavant Sciences itself became part of Sumitomo Dainippon group following a $3bn deal.