Gossamer Bio has lined up a partner to foot the development and commercialization bill for its make-or-break late-stage drug, expanding Phase 3 plans and paving the way for its launch outside the US.
Italian pharma Chiesi will pay Gossamer $160 million to kick off the collaboration. In addition to that initial payment — dubbed a “development reimbursement” — Chiesi will also split future costs for the candidate, seralutinib, and commit a total of $226 million in regulatory and sales milestones.
The deal is sizable for Gossamer, which has seen its market cap plummet to under $170 million over the past year and a half following mixed Phase 2 data — despite holding close to $300 million in cash, cash equivalents and marketable securities at the end of 2023. Partnering with Chiesi allows the San Diego biotech to “meaningfully deepen and rapidly accelerate our investment in seralutinib,” CEO Faheem Hasnain said in a statement.
Hasnain maintains seralutinib, an inhaled tyrosine kinase inhibitor, has big potential in targeting pathways of inflammation, proliferation and fibrosis. The seasoned biotech exec went all in on the candidate last May, axing the rest of the pipeline in a reorg.
Gossamer began a Phase 3 study of seralutinib in pulmonary arterial hypertension (PAH) late last year. With Chiesi now on board, it plans to start a new Phase 3 study in pulmonary hypertension associated with interstitial lung disease (PH-ILD) in mid-2025. They will also explore the drug’s use in other diseases.
Under the partnership, Gossamer will continue to lead development in PAH and PH-ILD, for which Chiesi will shoulder half of the cost except in the study that Gossamer already started. If seralutinib gets approved, the two companies will share commercial profits and losses in the US. Outside the US, Chiesi gets the exclusive right to commercialize and is on the hook for royalties.
PAH is believed to affect around 30,000 to 50,000 people in the US, according to Gossamer, and the prevalence should be similar in Europe. But the treatment landscape is shifting: In March, Merck won approval for Winrevair, the PAH therapy central to its $11.5 billion acquisition of Acceleron.
PH-ILD, on the other hand, is estimated to affect 60,000 to 100,000 patients in the US, with “a paucity of available treatments,” Hasnain said.