July 9, 2018

G1 Therapeutics Expands Executive Leadership Team with Appointment of John Demaree as Chief Commercial Officer and Stillman Hanson as General Counsel

July 09, 2018 — RESEARCH TRIANGLE PARK, N.C. (GLOBE NEWSWIRE) — G1 Therapeutics, Inc. (Nasdaq:GTHX), a clinical-stage oncology company, today announced appointments for two newly created executive leadership roles to support the company’s continued growth. John Demaree joins the company as Chief Commercial Officer and Stillman Hanson has been named General Counsel.

“We are excited to welcome John and Stillman to G1, and look forward to their contributions as we build out our commercial capabilities and expand our business development, legal and regulatory efforts,” said Mark Velleca, M.D., Ph.D., Chief Executive Officer. “John’s experience building a world-class commercial oncology organization will be invaluable as our three clinical-stage programs move toward key clinical and regulatory milestones. Moreover, Stillman’s extensive life sciences corporate legal experience will be critical as the company continues to grow and evolve from research and development to commercialization.”

Mr. Demaree has more than 20 years of oncology experience, building commercial capabilities and leading multiple successful product launches. Prior to joining G1, Mr. Demaree served as Vice President, Oncology Marketing at Astellas Pharma, where he was responsible for establishing and leading the oncology marketing function, including the successful launch of Xtandi® (enzalutamide). Mr. Demaree oversaw commercial strategy and execution for two approved products and three compounds in development, as well as market access and reimbursement strategy, product lifecycle management and external commercial collaborations. Previously, Mr. Demaree led oncology business development and alliance management at Abbott. He has also held marketing leadership positions at Novartis and Eli Lilly.

Mr. Hanson recently served as Associate General Counsel and Vice President at IQVIA, where he led the Quintiles legal team in the $20 billion merger of Quintiles and IMS Health to create QuintilesIMS (now IQVIA). In prior positions at Quintiles, he negotiated strategic contracts, represented Quintiles in its initial public offering and was responsible for its public company securities reporting. Before joining Quintiles in 2010, Mr. Hanson practiced corporate law, including merger and acquisitions, commercial contracting, securities reporting and corporate governance.

About G1 Therapeutics, Inc.

G1 Therapeutics, Inc. (G1) is a clinical-stage biopharmaceutical company focused on the discovery, development and commercialization of novel therapeutics for the treatment of cancer. Two of the company’s pipeline assets, trilaciclib and G1T38, are CDK4/6 inhibitors, a validated and promising class of oncology therapeutics. Trilaciclib and G1T38 have broad therapeutic potential in many forms of cancer and may serve as backbone therapy of multiple combination regimens. Trilaciclib is a short-acting IV CDK4/6 inhibitor designed to preserve hematopoietic stem cell and immune system function (myelopreservation) during chemotherapy. G1T38 is a potential best-in-class oral CDK4/6 inhibitor for use in combination with other targeted therapies. G1 is also advancing G1T48, a potential best-in-class oral selective estrogen receptor degrader, or SERD, which is targeted for the treatment of ER+ breast cancer.

G1 is based in Research Triangle Park, NC. For additional information, please visit www.g1therapeutics.com and follow us on Twitter @G1Therapeutics.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “may,” “will,” “expect,” “plan,” “anticipate,” “estimate,” “intend” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. Forward-looking statements in this news release include, but are not limited to, the therapeutic potential of trilaciclib, G1T38 and G1T48, and are based on G1’s expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties. Factors that may cause G1’s actual results to differ from those expressed or implied in the forward-looking statements in this press release are discussed in G1’s filings with the U.S. Securities and Exchange Commission, including the “Risk Factors” sections contained therein and include, but are not limited to, the inherent uncertainties associated with developing new products or technologies and operating as a development-stage company; G1’s ability to complete clinical trials for, obtain approvals for and commercialize any of its product candidates; G1’s ability to recruit and enroll patients in its studies; competition in the industry in which G1 operates; and market conditions. Except as required by law, G1 assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available.

About Hatteras Venture Partners

Hatteras Venture Partners is a venture capital firm based in Durham, NC with a focus on seed and early stage healthcare investing. The firm focuses on biopharmaceutical, healthcare IT, medical device, and diagnostic opportunities. Hatteras has approximately $450 million under management in five venture capital funds. The firm is led by a seasoned team of entrepreneurs and operators and has a long and successful track record of seed and early stage investing and company formation. To learn more about Hatteras Venture Partners, please visit www.hatterasvp.com.

Contact: Jeff Macdonald Head of Investor Relations / Public Relations 917-371-0940 [email protected]