Gossamer Bio filings document a clinical-stage biopharmaceutical issuer centered on seralutinib for PAH and PH-ILD. Form 8-K reports cover operating and financial results, Phase 3 PROSERA clinical disclosures, material agreements, unregistered equity issuances, resource-allocation actions, and Nasdaq listing-compliance notices involving its common stock.
Proxy materials describe board governance, shareholder voting matters, executive compensation, equity awards, and incentive-plan administration. The filing record also documents capital-structure matters and formal disclosures connected to a late-stage pulmonary hypertension development company.
Gossamer Bio, Inc. (GOSS) announced that it submitted its first New Drug Application in September 2026 for seralutinib to treat pulmonary arterial hypertension. The application is supported by the Phase 3 PROSERA Study as one adequate and well-controlled clinical investigation, together with confirmatory evidence from the Phase 2 TORREY Study and supportive analyses.
At a June 2026 pre-NDA meeting, the FDA characterized the statistical significance and magnitude of the treatment effect observed in PROSERA as review issues rather than filing issues. The FDA will decide whether to accept the application for filing after its initial review; Gossamer anticipates that could occur later this year. The FDA would assess the acceptability of the application’s individual elements, including efficacy and safety evidence, during substantive review.
Gossamer Bio, Inc. (GOSS) reported that director Gregory Austin Ciongoli holds a Pre-Funded Warrant giving the right to acquire 250 shares of Series A-1 non-voting convertible preferred stock, exercisable at $0.0001 per share on a direct basis. The warrant has no expiration date and is exercisable immediately, but, prior to Stockholder Approval under applicable Nasdaq rules for the related private placement, it is exercisable only for Series A-1 non-voting convertible preferred stock. After Stockholder Approval, it will be exercisable only for shares of Gossamer Bio common stock, with each Series A-1 share automatically converting into a number of common shares equal to $1,000 divided by $11.20, subject to beneficial ownership limitations.
Gossamer Bio, Inc. (GOSS) is asking stockholders at an October 27, 2026 virtual special meeting to approve, under Nasdaq Listing Rules 5635(c) and 5635(d), the issuance of common stock underlying a large private placement involving pre-funded warrants, FDA approval warrants and three series of convertible preferred stock. The Initial Closing on August 24, 2026 raised approximately $25.0 million, and a Second Closing, contingent on 2026 NDA acceptance for seralutinib in pulmonary arterial hypertension, is expected to raise a further approximately $125.0 million before expenses, with additional upside tied to FDA approval warrants.
If approved, up to about 20,086,929 shares of common stock could ultimately be issuable upon warrant exercise and preferred conversion, exceeding 20% of the 6,116,391 shares outstanding as of September 14, 2026 and materially diluting existing holders. Before approval, the instruments are limited to preferred stock and carry a 4x liquidation preference; after approval they convert into common stock and lose that separate preference. The company also recently effected a 1-for-80 reverse stock split on September 10, 2026, and all share figures are presented on a post-split basis.
Gossamer Bio, Inc. (GOSS) reported that its Board appointed Gregory A. Ciongoli as a Class III director, effective September 16, 2026, with a term running until the 2027 annual meeting of stockholders. He will also serve on the Audit Committee and has been determined to be an independent director under Nasdaq Global Select Market rules.
Under the non-employee director compensation program, he will receive an annual cash retainer of $40,000 for Board service and $7,500 for Audit Committee service, plus equity compensation to be determined at a future date. Ciongoli is Founder and Managing Partner of Adiumentum Capital Management and previously was a Partner at the Baupost Group, and he sits on several other biopharmaceutical boards.
The company notes that Ciongoli was a purchaser in Gossamer’s 2026 private placement, holding or agreeing to purchase pre-funded and FDA approval warrants tied to preferred stock that are exercisable, following stockholder approval, for approximately 22,337, 111,687, and 66,845 shares of common stock, respectively. These figures reflect Gossamer’s 1-for-80 reverse stock split effectuated on September 10, 2026.
Gossamer Bio, Inc. (GOSS) has implemented a 1-for-80 reverse stock split of its common stock, effective at 11:59 p.m. Eastern Time on September 10, 2026, along with a proportionate reduction in authorized share counts. Every 80 pre-split shares have been reclassified into 1 post-split share, with fractional positions rounded up to the nearest whole share.
The number of authorized common shares was reduced from 4,000,000,000 to 50,000,000, and total authorized capital stock from 4,070,000,000 to 120,000,000. Conversion rates and exercise prices on convertible notes, warrants, prefunded warrants, and equity awards were proportionately adjusted, and plan reserves were reduced. The stock is expected to trade on a split-adjusted basis on Nasdaq under “GOSS” on September 11, 2026, and the reverse split is intended to help regain compliance with Nasdaq’s $1.00 minimum bid price requirement by the October 5, 2026 compliance date.
Gossamer Bio, Inc. (GOSS) is implementing a 1-for-80 reverse stock split of its common stock, together with a proportionate reduction in authorized shares of common and total capital stock. The reverse split and authorized share reduction are expected to become effective on September 10, 2026 at 11:59 p.m. Eastern Time, with split-adjusted trading on the Nasdaq Global Select Market beginning September 11, 2026 under the same ticker GOSS and a new CUSIP. The reverse split is intended to help the company regain compliance with Nasdaq’s minimum bid price requirement, while leaving each stockholder’s percentage ownership and voting power essentially unchanged apart from minor rounding adjustments for fractional shares.
Gossamer Bio, Inc. (GOSS), a Delaware biotechnology corporation, filed a new notice of an exempt securities offering under Regulation D, Rule 506(b).
The offering involves options, warrants or other rights to acquire securities and the securities issuable upon exercise. The company reports that $25,000,000 of securities have been sold and that $125,000,000 remain available to be sold. The date of first sale is listed as August 20, 2026. Leerink Partners LLC and Cantor Fitzgerald & Co. are identified in the sales compensation section, and stated finders’ fees are $0.
Gossamer Bio, Inc. (GOSS) is calling a virtual special stockholder meeting to approve, under Nasdaq Listing Rules 5635(c) and 5635(d), a large potential issuance of Common Stock tied to an August 20, 2026 private placement. The financing includes Initial Closing pre-funded warrants already sold for aggregate gross proceeds of $25.0 million, plus a Second Closing tied to FDA acceptance of Gossamer’s NDA for seralutinib in pulmonary arterial hypertension that is expected to provide an additional $125.0 million of gross proceeds, excluding any FDA Approval Warrant exercises.
If stockholders approve Proposal 1, multiple series of convertible Preferred Stock, Pre-Funded Warrants and FDA Approval Warrants could convert or be exercised into up to an aggregate of approximately 1,606,953,812 shares of Common Stock, compared with 488,846,722 shares outstanding as of August 25, 2026, significantly diluting existing holders and creating substantial resale overhang. Approval would also remove a separate liquidation preference on the Preferred Stock and allow automatic conversion into Common Stock, while failure to approve would leave the Preferred Stock outstanding with its liquidation preference, restrict Gossamer’s ability to issue additional equity and could cause the Second Closing commitments to terminate after December 31, 2026.
Gossamer Bio, Inc. (GOSS) reports that its Board of Directors approved an amendment and restatement of the company’s bylaws, effective September 3, 2026. The Amended and Restated Bylaws reduce the stockholder meeting quorum requirement from holders of a majority to holders of one third (1/3) in voting power of the company’s capital stock issued and outstanding and entitled to vote, present in person, by remote communication if applicable, or represented by proxy, unless a higher threshold is required by law, the certificate of incorporation, or the bylaws.
Gossamer Bio, Inc. (GOSS) reported that executive officer Christian Waage, EVP, Tech Ops and Admin, received a grant of stock options covering 2,900,026 shares of common stock at an exercise price of $0.175 per share. The options expire on 2036-08-23 and vest based on future milestones and service conditions tied to FDA approval of seralutinib or, if approval is delayed, over time following the second anniversary of the grant date.