Management team strengthened as company advances lead product candidate

Biopharmaceutical executive, physician and scientist brings diverse expertise and oncology experience

Research Triangle Park, NC, May 20, 2014 – G1 Therapeutics, Inc., a privately held pharmaceutical company that focuses on the discovery and development of novel small molecules for use in cancer therapy and biodefense applications, today announced the appointment of Mark Velleca, M.D., Ph.D. as chief executive officer, effective immediately. Previously, Dr. Velleca was instrumental in founding, building, and leading CGI Pharmaceuticals up through its acquisition by Gilead Sciences in 2010. He most recently served as executive vice president at The Leukemia & Lymphoma Society (LLS).

“We are delighted to welcome Mark to G1 as our CEO,” said Seth Rudnick, M.D., chairman of G1’s board of directors. “The combination of Mark’s well-established relationships with the oncology community and his background as a board-certified physician, scientist and industry executive make him an ideal leader for G1 as we prepare to advance our lead product candidate for chemotherapy-induced myelosuppression to IND status this summer and explore additional oncology opportunities for our novel kinase inhibitors.”

Dr. Velleca said, “I’m honored and excited to be joining G1 at such a pivotal time for the company. With its novel CDK4/6 platform, G1 has the potential to fulfill significant unmet needs for cancer patients. I look forward to working closely with G1’s talented and seasoned team, including its founders, board, investors, and scientists, to successfully grow the company and advance its pipeline of innovative therapeutics.”

Dr. Velleca joined LLS in 2012 as chief policy and advocacy officer and was responsible for the strategy and implementation of its legislative and regulatory policy initiatives. Prior to LLS, Dr. Velleca was a founder and served as senior vice president of CGI Pharmaceuticals, where he guided the company from its inception through its establishment as a drug discovery company that brought multiple drug candidates into clinical trials. When CGI was acquired by Gilead Sciences in 2010, Dr. Velleca served as a senior advisor to Gilead. He helped the company build its oncology pipeline through prioritization of internal programs, academic partnerships, in-licensing, technology deals and acquisitions. Earlier in his career, Dr. Velleca was an attending physician at Yale New Haven Hospital and on the faculty of Yale University School of Medicine.

Dr. Velleca earned a B.S. in biology Cum Laude from Yale University and an M.D. and Ph.D. in
neuroscience from Washington University in St. Louis. He has served on the board of directors of
BioMarker Strategies, a Johns Hopkins-founded oncology diagnostics company, as well as the scientific
advisory board of Intellikine, a drug discovery company focused on oncology and autoimmune disease
therapeutics that was acquired by Takeda in 2011.

About G1 Therapeutics, Inc.

G1 Therapeutics, Inc. is a privately held pharmaceutical company based in Research Triangle Park, NC that focuses on the discovery and development of novel small molecules for use in cancer therapy and biodefense applications. These molecules are being developed for targeting specific proteins associated with cell proliferation and growth and have demonstrated robust anti-tumor activity in animal models.  Such therapies may be useful to protect the bone marrow and other organs, including the kidney and lung, from toxic insult. In October 2013, the company raised $12.5 million in a Series A financing that will enable it to advance its lead clinical candidate into clinical trials for the treatment of chemotherapy-induced myelosuppression. Visit www.g1therapeutics.com for more information.