GRTX

Galera Therapeutics, Inc. (Nasdaq: GRTX), a clinical-stage biopharmaceutical company focused on developing and commercializing a pipeline of novel, proprietary therapeutics that have the potential to transform radiotherapy in cancer, today announced that tumor outcomes data from its Phase 3 ROMAN trial of avasopasem for severe oral mucositis (SOM) and final data from its Phase 2 AESOP trial of avasopasem for chemoradiotherapy-induced esophagitis will be highlighted in two presentations at the upcoming 2022 American Society for Radiation Oncology (ASTRO) Annual Meeting, taking place October 23-26, 2022 in San Antonio, Texas. Additionally, poster presentations will highlight the Phase 2 EUSOM trial of avasopasem for SOM in Europe and the ongoing GRECO-1 trial of rucosopasem for non-small cell lung cancer.

Presentation Details

Title: Tumor Outcomes for ROMAN: Phase 3 Trial of Avasopasem Manganese (GC4419) for Severe Oral Mucositis (SOM) in Patients Receiving Chemoradiotherapy (CRT) for Locally Advanced Head and Neck Cancer (LAHNC)Abstract Number: 280Presenter: Carryn M. Anderson, M.D., University of Iowa Hospitals & Clinics Session Title: H&N 3 - Toxicity Mitigation and HPV-Unrelated Head and Neck Cancer - Life Beyond De-IntensificationSession Date and Time: Wednesday, October 26, 2022 | 12:40 p.m. CDTSession Location: Henry B. Gonzalez Convention Center, Room 214

Title: AESOP: Phase 2 Open-Label Trial of Avasopasem Manganese (GC4419) for Reduction of Esophagitis in Patients Receiving Chemoradiotherapy for Nonmetastatic Lung CancerAbstract Number: 1124Presenter: Bryan G. Allen, M.D., Ph.D., University of Iowa Hospitals & Clinics Session Title: Lung 3 - Optimizing Radiation Dose, Volume, and Concomitant Systemic AgentsSession Date and Time: Wednesday, October 26, 2022 | 10:50 a.m. CDTSession Location: Henry B. Gonzalez Convention Center, Room 303

Poster Q&A Details

Title: GRECO-1: Phase 1/2 Study of Stereotactic Body Radiation Therapy (SBRT) with or without Rucosopasem (GC4711) for Early Stage, Peripheral or Centrally Located Non-Small Cell Lung Cancer (NSCLC)Abstract Number: 2841Presenter: Puneeth Iyengar, M.D., Ph.D., UT Southwestern Medical CenterSession Title: Poster Q&A 01 - Lung Cancer and DEIHSession Date and Time: Sunday, October 23, 2022 | 4:45 p.m. CDTSession Location: Henry B. Gonzalez Convention Center, Exhibit Hall 1

Title: EUSOM: Phase 2 Trial of Avasopasem Manganese (GC4419) for Oral Mucositis in Patients Receiving Chemoradiotherapy for Locally Advanced, Nonmetastatic Head and Neck CancerAbstract Number: 2687Presenter: Jordi Giralt, M.D., Ph.D., Vall d'Hebron University HospitalSession Title: Poster Q&A 09 - Head & Neck Cancer and Health Services ResearchSession Date and Time: Wednesday, October 26, 2022 | 10:30 a.m. CDTSession Location: Henry B. Gonzalez Convention Center, Exhibit Hall 1

The titles of the abstracts are currently available in the ASTRO digital program, with the full abstracts available on Friday, October 21, 2022, at 5 p.m. CDT.

About Galera Therapeutics

Galera Therapeutics, Inc. is a clinical-stage biopharmaceutical company focused on developing and commercializing a pipeline of novel, proprietary therapeutic candidates that have the potential to transform radiotherapy in cancer. Galera’s selective dismutase mimetic product candidate avasopasem manganese (GC4419, also referred to as avasopasem) is being evaluated for radiotherapy-induced toxicities. The Company’s second product candidate, rucosopasem manganese (GC4711, also referred to as rucosopasem), is in clinical-stage development to augment the anti-cancer efficacy of stereotactic body radiation therapy in patients with non-small cell lung cancer and locally advanced pancreatic cancer. Galera is headquartered in Malvern, PA. For more information, please visit www.galeratx.com.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including without limitation statements regarding: the expectations surrounding the continued advancement of Galera’s product pipeline; the potential safety and efficacy of Galera’s product candidates and their regulatory and clinical development; the Company’s ability to achieve its goal of transforming radiotherapy in cancer treatment with its selective dismutase mimetics; and the potential of rucosopasem to augment the anti-cancer efficacy of SBRT in patients with NSCLC and LAPC. These forward-looking statements are based on management’s current expectations. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause Galera’s actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including, but not limited to, the following: Galera’s limited operating history; anticipating continued losses for the foreseeable future; needing substantial funding and the ability to raise capital; Galera’s dependence on avasopasem manganese (GC4419); uncertainties inherent in the conduct of clinical trials; difficulties or delays enrolling patients in clinical trials; the FDA’s acceptance of data from clinical trials outside the United States; undesirable side effects from Galera’s product candidates; risks relating to the regulatory approval process; failure to capitalize on more profitable product candidates or indications; ability to receive or maintain Breakthrough Therapy Designation or Fast Track Designation for product candidates; failure to obtain regulatory approval of product candidates in the United States or other jurisdictions; ongoing regulatory obligations and continued regulatory review; risks related to commercialization; risks related to competition; ability to retain key employees and manage growth; risks related to intellectual property; inability to maintain collaborations or the failure of these collaborations; Galera’s reliance on third parties; the possibility of system failures or security breaches; liability related to the privacy of health information obtained from clinical trials and product liability lawsuits; unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives; environmental, health and safety laws and regulations; the impact of the COVID-19 pandemic on Galera’s business and operations, including preclinical studies and clinical trials, and general economic conditions; risks related to ownership of Galera’s common stock; the possibility of Galera’s common stock being delisted from The Nasdaq Global Market; and significant costs as a result of operating as a public company. These and other important factors discussed under the caption “Risk Factors” in Galera’s Annual Report on Form 10-K for the year ended December 31, 2021 filed with the U.S. Securities and Exchange Commission (SEC) and Galera’s other filings with the SEC could cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. Any forward-looking statements speak only as of the date of this press release and are based on information available to Galera as of the date of this release, and Galera assumes no obligation to, and does not intend to, update any forward-looking statements, whether as a result of new information, future events or otherwise.

Investor Contacts:Christopher DegnanGalera Therapeutics, Inc.610-725-1500cdegnan@galeratx.com

William WindhamSolebury Strategic Communications646-378-2946wwindham@soleburystrat.com

Media Contact:Zara LockshinSolebury Strategic Communications330-417-6250zlockshin@soleburystrat.com