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. filed a Post-Effective Amendment No. 1 to its Form S-3 to register up to $200.0 million of securities in the aggregate, including common stock, preferred stock, debt securities, warrants and units. The amendment states it is being filed because the company expects it will no longer be a "well-known seasoned issuer." The prospectus permits offers "from time to time after the effective date" and requires a prospectus supplement for terms and amounts of each offering. The filing also discloses the company’s Nasdaq symbol (GOSS) and a March 16, 2026 last reported sale price of $0.456 per share.
683 Capital Management, LLC and related reporting persons reported beneficial ownership in Gossamer Bio. As of March 2, 2026, the reporting persons beneficially owned 8,000,000 shares of common stock plus warrants exercisable for 4,331,304 shares, totaling 12,331,304 shares, or 5.23% of common stock on the basis described in the filing. The filing states the 4,331,304 warrants are currently exercisable and that voting and dispositive power over these securities is shared among the reporting persons.
The percentage uses an outstanding share base of 231,456,247 common shares as of October 31, 2025, plus the 4,331,304 exercisable-warrant shares, per the disclosure.
Gossamer Bio, Inc. received an amended Schedule 13D from New Enterprise Associates–affiliated entities led by Growth Equity Opportunities 18 VGE, LLC, updating their ownership in the company’s common stock.
On February 23, 2026, GEO completed open‑market public sales totaling 17,093,034 shares of Gossamer Bio common stock at a weighted average price of $0.3906 per share, with trade prices ranging from $0.3320 to $0.6363 per share.
After these transactions, as of February 23, 2026 GEO is the record owner of 1,000,000 shares and may be deemed to beneficially hold an additional 3,065,134 shares underlying GEO warrants, for total GEO‑related beneficial ownership of 4,065,134 shares, or 1.7% of Gossamer Bio’s outstanding common stock. That percentage is based on 234,521,381 shares, including 231,456,247 shares outstanding as of October 31, 2025 plus the GEO warrants. Voting and dispositive power over these shares is reported as shared among GEO, affiliated NEA entities, and several individual managers, each of whom disclaims beneficial ownership beyond shares held of record.
Gossamer Bio reported topline Phase 3 PROSERA results for seralutinib in pulmonary arterial hypertension. The trial did not meet its primary endpoint, with a Hodges‑Lehmann placebo‑adjusted improvement in six‑minute walk distance of 13.3 meters at Week 24 and a p‑value of 0.0320 versus a prespecified α of 0.025.
All four key secondary endpoints, including NT‑proBNP reduction, clinical improvement, time‑to‑clinical worsening and REVEAL Lite 2 risk score, numerically favored seralutinib, with especially strong effects in prespecified intermediate‑ and high‑risk patients and in connective tissue disease–associated PAH. Seralutinib was generally well tolerated, though liver enzyme elevations and cough were more frequent than with placebo.
The company plans to meet with the U.S. FDA to discuss a potential development path and is pausing enrollment in the SERANATA Phase 3 study while it assesses PROSERA, including regional differences in placebo response and forthcoming CT functional respiratory imaging substudy data.
Gossamer Bio, Inc. received an updated large-holder disclosure from Octagon Capital. Octagon Capital Advisors LP, Octagon Investments Master Fund LP, and Ting Jia jointly report beneficial ownership of 15,141,425 Gossamer Bio common shares, representing 6.5% of the outstanding stock.
This stake includes 13,915,371 common shares held by the Master Fund and warrants to purchase up to 1,226,054 additional shares at an exercise price of $2.04 per share, expiring on July 24, 2028. The ownership percentage is based on 231,456,247 shares outstanding as of October 31, 2025, plus the warrant shares.
The reporting persons state that the securities were acquired and are held in the ordinary course of business, and not for the purpose of changing or influencing control of Gossamer Bio.
Gossamer Bio, Inc. has filed an automatic shelf registration statement on Form S-3 as a well-known seasoned issuer. This filing allows the company to offer common stock, preferred stock, debt securities, warrants and units in one or more future offerings using prospectus supplements.
Any specific terms, prices and uses of proceeds will be detailed in later supplements. Gossamer Bio is a late-stage clinical biopharmaceutical company focused on developing seralutinib for pulmonary hypertension, including PAH and PH-ILD. Its common stock trades on the Nasdaq Global Select Market under the symbol GOSS, with a reported price of $2.64 per share on January 27, 2026.
Gossamer Bio, Inc. received an amended Schedule 13G filing showing that BlackRock, Inc. beneficially owns 15,065,708 shares of its common stock as of 12/31/2025. This position represents 6.5% of Gossamer Bio’s outstanding common shares.
BlackRock reports sole voting power over 14,859,077 shares and sole dispositive power over 15,065,708 shares, with no shared voting or dispositive power. The filing explains that these securities are held by certain BlackRock business units and that various underlying persons have rights to dividends or sale proceeds, but no individual holds more than five percent of the total outstanding shares.
BlackRock certifies that the shares were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control of Gossamer Bio.
Gossamer Bio (GOSS) furnished a Form 8-K announcing it issued a press release reporting financial results for the quarter ended September 30, 2025. The press release is included as Exhibit 99.1.
The company noted that the information in this item, including Exhibit 99.1, is being furnished and not filed under the Exchange Act and is not subject to Section 18 liabilities, nor incorporated by reference except as specifically stated. The report was signed by Bryan Giraudo, Chief Financial Officer and Chief Operating Officer.
Gossamer Bio (GOSS) reported Q3 2025 results, showing higher collaboration revenue but wider losses. Revenue was $13.3 million for the quarter, up from $9.5 million a year ago, driven by revenue from contracts with collaborators. For the nine months, revenue was $34.7 million versus $105.3 million last year, when results included $88.8 million of license revenue.
The company posted a Q3 net loss of $48.2 million (basic/diluted loss per share $0.21), compared with a $30.8 million loss a year earlier, as research and development expenses rose to $45.5 million. Year to date, operating cash flow was negative $123.0 million.
As of September 30, 2025, cash and cash equivalents were $8.9 million and marketable securities were $171.3 million. Total assets were $208.8 million against total liabilities of $291.2 million, resulting in a stockholders’ equity (deficit) of $(82.3) million. Long‑term convertible senior notes had a net carrying amount of $198.3 million. The company reports that Chiesi accounted for 100% of revenue during the nine‑month period under the collaboration agreement.
Robert Paul Smith Jr., identified as an Officer (Chief Commercial Officer) of Gossamer Bio, Inc. (GOSS), reported a securities acquisition on 10/01/2025. The filing shows an award of 162,500 performance stock units issued at $0 that will vest in full upon the earlier of (i) approval of a new drug application for seralutinib or (ii) a change in control, in either case on or before the fourth anniversary of the grant, and subject to his continuous service to the company. The filing also discloses 25,000 shares held indirectly by a family trust. The Form 4 was submitted by one reporting person and signed by an attorney-in-fact on 10/02/2025.