Gossamer Bio and Chiesi Farmaceutici (the Chiesi Group) have announced a worldwide partnership and licence agreement to develop and market seralutinib for pulmonary hypertension.

The partnership will leverage the strengths of both companies to enhance efforts in treating pulmonary arterial hypertension (PAH) and to expedite the product development for pulmonary hypertension associated with interstitial lung disease (PH-ILD).

Chiesi will offer its global expertise in respiratory and rare disease treatment, as well as inhaled drug development and commercialisation while Gossamer will contribute PAH and PH-ILD development and commercialisation teams.

Seralutinib is administered via a dry powder inhaler.

The collaboration follows the positive outcome of the Phase II TORREY clinical trial in PAH patients, prompting Gossamer to launch the Phase III PROSERA study in 2023.

The companies will begin an international Phase III registration study of seralutinib in PH-ILD by mid-2025 and are considering additional indications.

Gossamer will head worldwide seralutinib development for PAH and PH-ILD indications.

Development expenditures will be shared, other than for the PROSERA study, which remains Gossamer's financial responsibility.

Commercial profits and losses incurred in the US will be divided equally between the companies, with Gossamer handling commercialisation and sales booking for PAH and PH-ILD.

Gossamer Bio and Chiesi will contribute equally to the product’s commercial efforts.

Chiesi will handle the US commercialisation works for any additional indications and exclusively commercialise seralutinib outside the US.

In return, the company will make royalty payments to Gossamer on net product sales.

The agreement stipulates a $160m development reimbursement to Gossamer from Chiesi, along with potential regulatory and sales-based milestone payments of $146m and $180m respectively.

Gossamer co-founder, chairman and CEO Faheem Hasnain stated: “This partnership with Chiesi allows us to meaningfully deepen and rapidly accelerate our investment in seralutinib as a potential treatment for PAH, PH-ILD and other indications of high unmet medical need.

“We are particularly thrilled that this collaboration enables seralutinib to move directly into a Phase III trial in PH-ILD, an indication with a paucity of available treatments, and a disease which we believe seralutinib is specifically designed to address.”