Despite a Phase 3 miss, Gossamer Bio is full steam ahead for its lung disease asset, pointing to previous “review issues” at the FDA as one of the reasons to continue development.
Gossamer Bio is tripling down on its pulmonary hypertension candidate after a late-stage failure, regaining rights from Chiesi and sharing plans for an upcoming FDA submission.
In February, Gossamer’s inhaled tyrosine kinase inhibitor seralutinib failed to significantly improve functional performance in a Phase 3 pulmonary arterial hypertension (PAH) study, sending the California biotech’s stock spiraling.
Now, Gossamer has shared a flurry of updates around the program, including September FDA submission plans that would set up the company for a regulatory decision by August of next year.
“Our conviction in the program has never been stronger,” Gossamer CEO Faheem Hasnain said on a Monday investor call.
FDA minutes from a June pre-NDA Type B meeting have unearthed new insights about the agency’s position regarding Gossamer’s Phase 3 trial, called PROSERA.
“Based on the meeting minutes, the FDA characterized the degree of statistical significance and the magnitude of the treatment effect observed in PROSERA as review issues rather than filing issues,” Gossamer said.
Based on that, Gossamer plans on filing a a new drug application based off PROSERA, plus data from a Phase 2 trial called TORREY and other analyses. In the study, patients demonstrated a placebo-adjusted improvement of 13.3 meters in a six-minute walk distance test at 24 weeks, with a p-value of 0.0320. This missed the prespecified statistically significance threshold of 0.025.
There was no specific discussion about p-value with the agency in the pre-meeting, Chief Development Officer Caryn Peterson said on the call, though CFO Bryan Giraudo pointed to the FDA’s recent statements indicating that a p-value of 0.05 is acceptable for trials in orphan or rare diseases.
“Clearly, there has been a shift when it comes to situations like ours,” Giraudo said.
Efficacy and safety considerations would be covered by the FDA during an official review of the application.
“Key remaining questions are whether FDA ultimately approves seralutinib given the PROSERA data, and, if approved, how it fits commercially within the evolving PAH treatment paradigm given what we see as a relatively modest treatment effect,” Guggenheim analysts wrote in a Monday morning note.
Seralutinib collaborator Chiesi has also cut ties, according to Gossamer’s Monday press release, which framed the decision as a mutual agreement between the two companies.
“Our friends at Chiesi are going through a bit of a reorganization of their own business,” Giraudo said on the call, citing the Italian company’s renewed focus on ultrarare diseases. Chiesi has not responded to BioSpace’s request for comment as of publication.
Gossamer is reacquiring global development and commercial rights for seralutinib, with Chiesi paying a one-time $5 million fee to settle all obligations, according to the release.
Initially inked in 2024, the 50/50 U.S. profit share partnership had granted Italy-based Chiesi the exclusive right to commercialize seralutinib outside of the U.S. Under the new agreement, Chiesi could collect capped royalties on worldwide net sales of seralutinib, plus payments if certain regulatory and commercial milestones are met.
“Our intention is to proceed as an independent company,” CEO Hasnain said, adding that Gossamer doesn’t currently need to establish another partnership.
As of June 30, the biotech only had about $57 million in cash, cash equivalents and marketable securities on hand. The company is planning a reverse stock split this quarter or right after the quarter ends, a move that is often made to avoid delisting.
Gossamer’s stock rose 25% on today’s news, up from 13 cents to 16 cents per share this morning.
“Our stockholders have approved the capital structure actions designed to reduce near-term debt and better position the company for the work ahead,” Hasnain said on the call.
“After years of disciplined execution, we are now closer than ever to bringing forward what we believe can be a first-in-class, important new medicine for PAH patients who need better options,” the CEO concluded in a prepared statement. “There has never been a more exciting time in Gossamer’s history, and we look forward to the milestones ahead.”
