Gossamer Bio Stock Surges 25% on Clear FDA Path for Seralutinib

Gossamer Bio (NASDAQ: GOSS) shares surged by 25% on Monday after the company announced a clear regulatory pathway for its pulmonary arterial hypertension (PAH) drug, seralutinib, and the reacquisition of the treatment's full worldwide rights. The update provides investors with a concrete timeline for a potential key asset and consolidates its future revenue potential within the company.

FDA Outlines Path to Submission

Following a Pre-New Drug Application (NDA) Type B meeting with the U.S. Food and Drug Administration (FDA) in mid-June, Gossamer Bio received official minutes outlining a viable path forward. The company announced it now plans to submit its NDA for seralutinib for the treatment of PAH in September.

According to Gossamer, the FDA characterized questions regarding the statistical significance and treatment effect observed in the Phase 3 PROSERA study as "review issues" rather than "filing issues." This distinction is critical for investors, as it suggests the agency is likely to accept the application for a full review, clearing a major procedural hurdle. If the NDA is accepted, an FDA approval decision could be made in the third quarter of 2027.

Reacquisition of Seralutinib Rights

In a parallel strategic move, Gossamer announced it has regained full worldwide development and commercial rights for seralutinib from its partner, Chiesi, following the termination of their collaboration agreement. This dissolves a previous U.S. 50/50 profit-sharing arrangement and returns all ex-U.S. rights to Gossamer, giving it full control over the drug's potential commercial success.

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Under the termination agreement, Chiesi will make a one-time $5 million payment to Gossamer. In exchange for forgoing its collaboration rights, Chiesi is entitled to a capped royalty on worldwide net sales and payments upon achieving certain regulatory and commercial milestones. Gossamer made no upfront cash payment to reacquire the rights.

Corporate and Financial Health

The positive regulatory news comes as Gossamer takes steps to shore up its balance sheet. At a special meeting on July 14, stockholders approved an exchange of its 5.00% Convertible Senior Notes due 2027, which the company stated reduced its aggregate principal debt by approximately $115.9 million.

The company reported cash, cash equivalents, and marketable securities of approximately $57 million as of June 30. Stockholders also authorized the board to effect a reverse stock split, a common tool used by companies to manage their stock structure ahead of major catalysts.