Chiesi and Gossamer Bio Announce Transformative Global Collaboration to Develop and Commercialize Seralutinib in Pulmonary Arterial Hypertension and Other Respiratory Indications

• Strategic collaboration to leverage Chiesi's legacy of respiratory leadership and Gossamer Bio's development expertise in pulmonary hypertension.
• Gossamer to receive $160 million development reimbursement payment and eligible to receive up to $146 million in regulatory and $180 million in sales milestones.
• 50/50 commercial profit split in US and global development cost sharing arrangement.
• Chiesi obtains exclusive ex-US development, manufacturing, and commercial rights, with Gossamer to receive mid-to-high teens royalties on net sales.
• Gossamer and Chiesi plan to initiate in mid-2025 a Phase 3 trial of seralutinib in PH-ILD in addition to the ongoing Phase 3 trial in PAH

SAN DIEGO and PARMA, Italy, May 6, 2024 /PRNewswire/ -- Chiesi Farmaceutici S.p.A ("Chiesi Group"), an international, research-focused biopharmaceutical group, and Gossamer Bio, Inc. ("Gossamer") (Nasdaq: GOSS), a clinical-stage biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of pulmonary hypertension, today announced that they have entered into a global collaboration and license agreement to develop and commercialize seralutinib.

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), with the aim of expanding 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 a potential paradigm shifting therapy in PAH and PH-ILD, and we could not be more excited to partner with Gossamer to develop and bring this therapy to patients world-wide," said Giuseppe Accogli, CEO of Chiesi Group. "Gossamer shares Chiesi's commitment in using innovation to promote the health and well-being of people around the world and we are proud to add this collaboration as a key pillar to our next phase of growth."

"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," said Faheem Hasnain, Co-Founder, Chairman and CEO of Gossamer. "We are particularly thrilled that this collaboration enables seralutinib to move directly into a Phase 3 trial in PH-ILD, an indication with a paucity of available treatments, and a disease which we believe seralutinib is specifically designed to address."

Seralutinib is an inhaled PDGFRα/β, 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 2 TORREY Study in patients with PAH, Gossamer initiated the Phase 3 PROSERA Study in 2023. Gossamer and Chiesi plan to initiate a global Phase 3 registrational study in PH-ILD in mid-2025 and to evaluate seralutinib in additional indications of high unmet medical 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 US commercialization, including contributing 50 percent of commercial activities and booking of sales for PAH and PH-ILD. Chiesi will lead US commercialization for 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 outside of the US.

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.

Chiesi is devoted to advancing research, exploration, and advancement of groundbreaking treatments in the field of respiratory diseases, which holds a paramount position in our organization's strategic agenda. This collaboration introduces a significant and valuable addition to Chiesi's research and development portfolio, aligning perfectly with our strategy to bring innovative treatments to patients with unmet needs and support the healthcare community through transformative solutions.

About Chiesi Group
Chiesi is research-oriented international biopharmaceutical group that develops and markets innovative therapeutic solutions in respiratory health, rare diseases, and specialty care. The company's mission is to improve people's quality of life and act responsibly towards both the community and the environment.

By changing its legal status to a Benefit Corporation in Italy, the US, and France, Chiesi's commitment to create shared value for society as a whole is legally binding and central to company-wide decision-making. As a certified B Corp since 2019, we're part of a global community of businesses that meet high standards of social and environmental impact. The company aims to reach Net-Zero greenhouse gases (GHG) emissions by 2035.

With over 85 years of experience, Chiesi is headquartered in Parma (Italy), with 31 affiliates worldwide, and counts more than 7,000 employees. The Group's research and development centre in Parma works alongside 6 other important R&D hubs in France, the US, Canada, China, the UK, and Sweden.

For further information please visit www.chiesi.com 

About Gossamer Bio
Gossamer Bio is a clinical-stage biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of pulmonary arterial hypertension. Its goal is to be an industry leader in, and to enhance the lives of patients living with, pulmonary hypertension.