Gossamer Bio Announces Second Quarter 2019 Financial Results - Immuno-oncology candidate, GB1275, advances to clinic for selected solid tumor types - - Five active clinical trials across four clinical programs, with data

Gossamer Bio Announces Second Quarter 2019 Financial Results

- Immuno-oncology candidate, GB1275, advances to clinic for selected solid tumor types -

- Five active clinical trials across four clinical programs, with data readouts for all four programs expected in 2020 -

- Company to host conference call today at 4:30 p.m. ET -

SAN DIEGO, Calif., Aug. 8, 2019 - Gossamer Bio, Inc. (Nasdaq: GOSS), a clinical-stage biopharmaceutical company focused on discovering, acquiring, developing and commercializing therapeutics in the disease areas of immunology, inflammation and oncology, today announced its financial results for the quarter ended June 30, 2019 and provided a corporate update.

"Over the last several months, we have made significant progress advancing our diversified development portfolio, with five clinical trials now active," said Sheila Gujrathi, M.D., Co-Founder and Chief Executive Officer of Gossamer. "We are poised for a steady cadence of data readouts throughout 2020. Supported by a strong balance sheet and our experienced and growing team, we are well positioned to advance toward our goal of becoming an industry leader in immunology, inflammation and oncology."

GB001: Oral DP2 Antagonist for Asthma and Allergic Disease

GB002: Inhaled PDGFR Inhibitor for Pulmonary Arterial Hypertension (PAH)

GB004: Oral HIF-1 Stabilizer for Inflammatory Bowel Disease

GB1275: Oral CD11b Modulator for Oncology Indications

Financial Results for Quarter Ended June 30, 2019

Conference Call and Webcast

Gossamer's management team will host a conference call and live audio webcast at 4:30 p.m. ET today, Thursday, Aug. 8, 2019, to discuss its second quarter 2019 financial results and provide a corporate update.

The live audio webcast may be accessed through the Events/Presentations page in the Investors section of the Company's website at www.gossamerbio.com. Alternatively, the conference call may be accessed through the following:

Conference ID: 1393207

Domestic Dial-in Number: (866) 221-1654

International Dial-in Number: (470) 495-9466

Live Webcast: https://edge.media-server.com/mmc/p/o3xj5mjx

A replay of the audio webcast will be available for 30 days on the Investors section of the Company's website, www.gossamerbio.com.

Gossamer Bio is a clinical-stage biopharmaceutical company focused on discovering, acquiring, developing and commercializing therapeutics in the disease areas of immunology, inflammation and oncology. Its goal is to be an industry leader in each of these therapeutic areas and to enhance and extend the lives of patients suffering from such diseases.

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 forward-looking statements include, but are not limited to, statements regarding the anticipated timing of initiation and enrollment of clinical trials for our product candidates; plans to rapidly advance our product candidates; expectations on the timing of data readouts from our clinical studies; the potential clinical benefits of our product candidates; the indications we intend to pursue and our related business strategies; the expected timeframe for funding our operating plan with current cash, cash equivalents and marketable securities; and access to the Company's senior debt facility. 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, including, without limitation: potential delays in the commencement, enrollment and completion of clinical trials; the Company's dependence on third parties in connection with product manufacturing, research and preclinical and clinical testing; the success of Gossamer's clinical trials and preclinical studies for its product candidates; regulatory developments in the United States and foreign countries; unexpected adverse side effects or inadequate efficacy of the Company's product candidates that may limit their development, regulatory approval and/or commercialization, or may result in recalls or product liability claims; Gossamer's ability to obtain and maintain intellectual property protection for its product candidates; Gossamer's ability to comply with its obligations in the agreements under which it licenses intellectual property rights from third parties; the risk that the funding under the new senior debt facility may not be completed on the timeframe Gossamer expects, or at all, including as a result of Gossamer's failure to meet the conditions required for such funding or failure to comply with the affirmative and negative covenants under the credit facility; 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 to reflect events that occur or circumstances that exist after the date hereof. 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.

Gossamer Bio Statement of Operations

Condensed Consolidated Statement of Operations

(in thousands, except share and per share amounts)

Condensed Consolidated Balance Sheet