Form 8-K
8-K — Gossamer Bio, Inc.
Accession: 0001728117-26-000101
Filed: 2026-09-16
Period: 2026-09-16
CIK: 0001728117
SIC: 2834 (PHARMACEUTICAL PREPARATIONS)
Item: Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers
Item: Financial Statements and Exhibits
Documents
8-K — goss-20260916.htm (Primary)
EX-99.1 (ex991pr-newdirector.htm)
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8-K
8-K (Primary)
Filename: goss-20260916.htm · Sequence: 1
goss-20260916
0001728117FALSE00017281172026-09-162026-09-16
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): September 16, 2026
GOSSAMER BIO, INC.
(Exact name of Registrant as Specified in Its Charter)
Delaware 001-38796 47-5461709
(State or Other Jurisdiction
of Incorporation) (Commission File Number) (IRS Employer
Identification No.)
3115 Merryfield Row, Suite 120
San Diego, California 92121
(Address of Principal Executive Offices) (Zip Code)
(858) 684-1300
(Registrant’s Telephone Number, Including Area Code)
N/A
(Former Name or Former Address, if Changed Since Last Report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))
Securities registered pursuant to Section 12(b) of the Act:
Title of each class Trading
Symbol(s) Name of each exchange on which registered
Common Stock, $0.0001 par value per share GOSS Nasdaq Global Select Market
Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).
Emerging growth company ☐
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐
Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.
On September 16, 2026, upon the recommendation of the Nominating and Corporate Governance Committee, pursuant to the amended and restated bylaws of Gossamer Bio, Inc. (the “Company”), the Board of Directors (the “Board”) of the Company appointed Gregory A. Ciongoli to serve as a Class III director, effective September 16, 2026, with an initial term expiring at the Company’s 2027 annual meeting of stockholders. The Board also appointed Mr. Ciongoli as a member of the Audit Committee.
Mr. Ciongoli, age 51, has served as the Founder and Managing Partner of Adiumentum Capital Management, a Boston-based investment firm, since April 2024. Prior to Adiumentum, he was a Partner at the Baupost Group from 2007 to 2024, where he worked on a broad range of public and private equity investments. Mr. Ciongoli has served on the boards of directors of REGENXBIO Inc. since August 2026, Zymeworks, Inc. since August 2025 and Atara Biotherapeutics, Inc. since September 2024, having served as chair of the Board of Atara since September 2025. Mr. Ciongoli is also actively involved in a number of local not-for-profit organizations. Mr. Ciongoli graduated from Princeton University with an A.B. and received his M.B.A. from Harvard Business School.
Pursuant to the Company’s non-employee director compensation program, Mr. Ciongoli (i) will receive an annual cash retainer of $40,000 for service on the Board and (ii) an annual cash retainer of $7,500 for service on the Audit Committee. In addition, Mr. Ciongoli will be entitled to equity compensation specified in the Company’s non-employee director compensation program, although the Board determined that a standard initial award to Mr. Ciongoli will be made at a future date, and in a future amount, to be determined by the Board. Mr. Ciongoli has also entered into the Company’s standard form of Indemnification Agreement, the form of which was filed as Exhibit 10.14 to the Company's Form S-1, filed with the SEC on December 21, 2018, and incorporated herein by reference.
There is no arrangement or understanding between Mr. Ciongoli and any other person pursuant to which Mr. Ciongoli was appointed as a director. The Board has determined that Mr. Ciongoli is an independent director in accordance with the listing requirements of the Nasdaq Global Select Market.
As previously announced, on August 24, 2026, the Company held the initial closing of a private placement transaction (the “2026 PIPE”), pursuant to which Mr. Ciongoli was a purchaser under that certain Securities Purchase Agreement, dated August 20, 2026, by and among the Company and the purchasers named therein. Mr. Ciongoli (i) purchased initial closing pre-funded warrants exercisable for (a) prior to obtaining stockholder approval, up to 250 shares of Series A-1 preferred stock or (b) following the receipt of stockholder approval, approximately 22,337 shares of common stock, (ii) has agreed to purchase second closing pre-funded warrants exercisable for (a) prior to obtaining stockholder approval, up to 1,250 shares of Series A-2 preferred stock or (b) following the receipt of stockholder approval, approximately 111,687 shares of common stock (assuming a purchase price per second closing pre-funded warrant of $11.192; provided that such number will be increased if the purchase price per second closing pre-funded warrant is less than $11.192) and (iii) has agreed to purchase FDA approval warrants exercisable for (a) prior to obtaining stockholder approval, up to 1,000 shares of Series A-3 preferred stock or (b) following the receipt of stockholder approval, approximately 66,845 shares of common stock (or in lieu thereof, FDA approval warrant pre-funded warrants). The numbers set forth above take into account the Company’s 1-for-80 reverse stock split effectuated on September 10, 2026.
The description of the 2026 PIPE and the securities issued or issuable in connection therewith in Item 1.01 of the Current Report on Form 8-K filed by the Company with the Securities and Exchange Commission on August 21, 2026 is incorporated herein by reference.
On September 16, 2026, the Company issued a press release announcing Mr. Ciongoli’s appointment to the Board. A copy of the press release is attached hereto as Exhibit 99.1 and incorporated herein by this reference.
Item 9.01 Financial Statements and Exhibits.
(d) Exhibits
Exhibit No Description
99.1
Press Release dated September 16, 2026.
104 Cover Page Interactive Data File (embedded within the Inline XBRL document)
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.
GOSSAMER BIO, INC.
Date: September 16, 2026
By: /s/ Christian Waage
Christian Waage
Executive Vice President and General Counsel
EX-99.1
EX-99.1
Filename: ex991pr-newdirector.htm · Sequence: 2
Document
Exhibit 99.1
Gossamer Bio Appoints Greg Ciongoli to Board of Directors
SAN DIEGO — (BUSINESS WIRE) — September 16, 2026 — Gossamer Bio, Inc. (Nasdaq: GOSS), a clinical-stage biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease (PH-ILD), today announced that Greg Ciongoli has been appointed to the Company's Board of Directors, effective September 16, 2026. Mr. Ciongoli will also serve as a member of the Audit Committee.
Mr. Ciongoli has served as the Founder and Managing Partner of Adiumentum Capital Management, a Boston-based investment firm, since April 2024. Prior to Adiumentum, he was a Partner at the Baupost Group, where he worked on a broad range of public and private equity investments. Mr. Ciongoli also serves on the boards of directors of REGENXBIO Inc., Zymeworks, Inc. and Atara Biotherapeutics, Inc. He is actively involved in a number of local not-for-profit organizations. Mr. Ciongoli graduated from Princeton University with an A.B. and received his M.B.A. from Harvard Business School.
“We are pleased to welcome Greg to our Board,” said Faheem Hasnain, Chairman, Co-Founder and Chief Executive Officer of Gossamer Bio. “His deep investment experience and perspective on value creation will be an asset as we advance seralutinib toward a potential FDA approval and work to bring a new treatment option to patients with pulmonary hypertension.”
“I am excited to join the Gossamer Bio Board at such an important time for the Company,” said Mr. Ciongoli. “Seralutinib represents a compelling opportunity to address a serious unmet need, and I look forward to supporting the team as it advances the program.”
About Gossamer Bio
Gossamer Bio is a biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease. Its goal is to be an industry leader in, and to enhance the lives of patients living with, pulmonary hypertension.
Forward-Looking Statements
Gossamer cautions you that statements contained in this press release regarding matters that are not historical facts are forward-looking statements. These statements are based on the Company's current beliefs and expectations. Such statements include, but are not limited to, statements regarding advancing seralutinib toward a potential FDA approval and working to bring a new treatment option to patients with pulmonary hypertension. The inclusion of forward-looking statements should not be regarded as a representation by Gossamer that any of its plans will be achieved. Actual results may differ from those set forth in this press release due to the risks and uncertainties inherent in Gossamer's business, and other risks described in the Company's prior press releases and the Company's filings with the Securities and Exchange Commission (SEC), including under the heading “Risk Factors” in the Company's annual report on Form 10-K and any subsequent filings with the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and Gossamer
undertakes no obligation to update such statements. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.
For Investors and Media:
Bryan Giraudo, Chief Financial Officer & Chief Operating Officer
Gossamer Bio Investor Relations
ir@gossamerbio.com
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