Gossamer Bio and Chiesi Group Announce Global Partnership for Seralutinib Development and Commercialization

Gossamer Bio, Inc., a biopharmaceutical company operating in the clinical stage, has announced a new global collaboration and license agreement with Chiesi Farmaceutici S.p.A. The partnership is aimed at advancing the development and commercialization of seralutinib, a treatment targeting pulmonary hypertension, specifically in pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease (PH-ILD).

Under the agreement, Gossamer will receive a $160 million development reimbursement and could potentially gain up to $146 million in regulatory milestones and $180 million in sales milestones. The deal also includes a 50/50 profit share in the US markets for commercialization activities concerning PAH and PH-ILD. Moreover, the development costs will be shared globally, except for the Phase 3 PROSERA study, which Gossamer will finance entirely. Chiesi will handle exclusive commercialization rights outside the US, providing Gossamer with mid-to-high teens royalties on net sales.

The collaboration leverages Chiesi’s global expertise in respiratory and rare disease drug development and commercialization, along with Gossamer’s specialized teams in PAH and PH-ILD. This partnership aims to enhance the reach of seralutinib, making it available to a broader patient population suffering from pulmonary hypertension worldwide. Both companies plan to initiate a Phase 3 trial of seralutinib in PH-ILD by mid-2025.

According to Faheem Hasnain, Co-Founder, Chairman, and CEO of Gossamer, this collaboration significantly boosts their investment in seralutinib, particularly for treating PAH and PH-ILD. Giuseppe Accogli, Group CEO of Chiesi, echoed this sentiment, emphasizing the potential of seralutinib as a transformative therapy for these conditions and their shared vision of leveraging innovation to improve global health.

PAH impacts an estimated 30,000 to 50,000 people in the US, with similar figures in Europe. Current PAH treatments mainly consist of vasodilators and do not significantly alter the disease’s progression, contributing to a median five-year survival rate of about 57%. PH-ILD, although less frequently diagnosed, affects approximately 60,000 to 100,000 patients in the US. The condition has a lower median five-year survival rate of roughly 23%, with only one approved therapy available in the US and none outside it.

Seralutinib is designed as an inhaled therapy targeting PDGFRα/β, CSF1R, and c-KIT and is delivered via dry powder inhaler. Following promising results from the Phase 2 TORREY study in PAH patients, Gossamer began the Phase 3 PROSERA study in 2023. The upcoming global Phase 3 registrational study in PH-ILD reflects the companies’ commitment to exploring additional high-need indications for seralutinib.

In the US, Gossamer will lead the commercialization of seralutinib for PAH and PH-ILD, with both companies sharing commercial profits and efforts equally. Chiesi will handle US commercialization for additional indications. Outside the US, Chiesi will have exclusive rights to commercialize seralutinib and will provide Gossamer with royalties based on net sales.

This strategic partnership not only accelerates the development timeline but also broadens the geographical reach of seralutinib, potentially transforming the treatment landscape for pulmonary hypertension and addressing significant unmet medical needs.