Gossamer Bio and Chiesi Group announce transformative global collaboration to develop and commercialize seralutinib in pah, ph-ild & other indication

This global collaboration combines the strengths of both Chiesi and Gossamer to support ongoing work in pulmonary arterial hypertension (PAH) and to accelerate development in pulmonary hypertension associated with interstitial lung disease (PH-ILD), enabling the expansion of the seralutinib franchise to reach more patients with pulmonary hypertension world-wide. Patients will benefit from both Chiesi’s expertise in global respiratory, rare disease, and inhaled drug development and commercialization and Gossamer’s world-class PAH and PH-ILD development and commercialization teams.

Seralutinib is an inhaled PDGFR alpha/beta, CSF1R, and c-KIT inhibitor designed to be delivered via dry powder inhaler for the potential treatment of pulmonary hypertension. Following the positive readout of the Phase II TORREY Study in patients with PAH, Gossamer initiated the Phase III PROSERA Study in 2023.

Gossamer and Chiesi plan to initiate a global Phase III registrational study in PH-ILD in mid-2025 and to evaluate seralutinib in additional indications of high unmet need.

Under the terms of the agreement, Gossamer will continue to lead global development of seralutinib in PAH and PH-ILD, and the companies will evenly split development costs, except with respect to the PROSERA Study, for which Gossamer will remain financially responsible. In the US, the companies will evenly share commercial profits and losses. Gossamer will lead commercialization and book sales for PAH and PH-ILD in the US, with both companies contributing 50 percent of commercial efforts. Chiesi will lead US commercialization in additional indications. Chiesi will have the exclusive right to commercialize seralutinib outside of the US and will pay Gossamer an escalating mid-to-high teens royalty on net sales. Chiesi will pay Gossamer $160 million as a development reimbursement. Additionally, Gossamer will be eligible to receive up to $146 million in regulatory milestones and $180 million in sales milestones.