Chiesi buys into Gossamer's Winrevair rival, betting almost $500M

Italian pharma Chiesi is betting almost $500 million on Gossamer Bio's pulmonary arterial hypertension (PAH) candidate. 

The two will partner on global commercialization efforts for seralutinib, according to an announcement Monday, with Gossamer receiving $160 million in R&D reimbursements and $326 million biobucks up for grabs. Gossamer is currently enrolling a phase 3 seralutinib study for patients with PAH, the same indication that Merck recently won FDA approval for with Winrevair.

Gossamer will continue to spearhead development efforts and pay for the ongoing phase 3 study, with both companies sharing future trial costs. The smaller biotech will also lead U.S. commercialization efforts for PAH and pulmonary hypertension associated with interstitial lung disease (PH-ILD), though both companies will share costs. Chiesi will lead U.S. commercial efforts for any additional indications. 

Gossamer CEO Faheem Hasnain said the partnership allows the company to rapidly accelerate R&D investments for its sole asset, including a phase 3 trial launch in PH-ILD, an indication with few available treatments, Hasnain said in the release. 

More companies are looking to crack into the PAH market following the approval of Merck’s Winrevair earlier this year. The New Jersey pharma secured the asset—then sotatercept—after buying Accleron Pharma for $11.5 billion in September 2021. 

Not for nothing, Gossamer recently hired former top Merck lieutenant Bob Smith to spearhead commercial work. He previously led pre-approval commercial work for Winrevair and did similar work at Actelion before that biotech was bought by Johnson & Johnson. 

The fresh investment from Chiesi is much-needed good news for Gossamer, with seralutinib representing a last-gasp at commercial success. The biotech laid off 25% of staff a year ago to conserve as much capital for further development of the inhaled drug, despite not fully acing a previous phase 2 study.