RESEARCH TRIANGLE PARK, NC, April 15, 2015 – G1 Therapeutics, Inc., a clinical-stage pharmaceutical company developing small-molecule therapies to address significant unmet needs in oncology, announced today that new pre-clinical data on its lead compound G1T28 will be presented in a minisymposium and a poster session at the American Association for Cancer Research (AACR) Annual Meeting to be held April 18 – 22 at the Pennsylvania Convention Center in Philadelphia. G1T28 is a clinical stage, small molecule inhibitor of cyclin dependent kinases 4 and 6 (CDK4/6).

"These data demonstrate that G1T28 induces a significant, rapid and reversible arrest of hematopoietic stem and progenitor cells, which can reduce chemotherapy-induced myelosuppression," said Raj Malik, MD, Chief Medical Officer of G1 Therapeutics. "Results of these pre-clinical studies support the continued advancement of the IV formulation of G1T28 in clinical trials to protect the bone marrow of patients with cancer from damage by chemotherapy."

Details of the minisymposium and poster session are as follows:

Session Title: Cell Cycle Mechanisms of Anticancer Drug Action, Minisymposium
Presentation Title: G1T28, a novel CDK4/6 inhibitor, protects murine hematopoietic stem and progenitor cells from cytotoxic chemotherapy
Presentation Time: Sunday, April 19, 3:35 - 3:50 p.m.
Location: Room 120, Pennsylvania Convention Center
Authors: Jessica A. Sorrentino, Shenghui He, John E. Bisi, Patrick J. Roberts, Jay C. Strum, Norman E. Sharpless

These data demonstrate that G1T28 is a highly potent CDK4/6 inhibitor that causes robust and transient inhibition of hematopoietic stem and progenitor cells (HSPCs). G1 cell cycle arrest of HSPCs at the time of administration of the chemotherapy drug 5FU significantly lessens chemotherapy-induced myelosuppression. This benefits all hematopoietic lineages (red cells, neutrophils, platelets and lymphocytes) and attenuates the acute myelosuppression of each cycle of chemotherapy.

Session Title: Novel Agents and Mechanisms of Action, Poster Session
Presentation Title: Pre-clinical characterization of G1T28, a novel CDK4/6 inhibitor for protection of bone marrow from cytotoxic chemotherapies
Presentation Time: Monday, April 20, 8 a.m. - 12 p.m.
Location: Section 32, Number 27
Authors: John E. Bisi, Hannah S. White, Jessica A. Sorrentino, Patrick J. Roberts, Jay C. Strum

These data establish G1T28 as a novel, potent and selective CDK4/6 inhibitor that induces a transient and reversible G1 cell cycle arrest in CDK4/6-dependent cells, thereby decreasing chemotherapy-induced DNA damage and apoptosis. Importantly, the anti-tumor activity of chemotherapy in CDK4/6-independent cells is unaffected by G1T28.

Full abstracts for each presentation and additional information on the meeting can be found on the AACR web site: http://www.aacr.org/Meetings/Pages/MeetingDetail.aspx?EventItemID=25#.VSgAJ_nF-uQ.

About G1 Therapeutics, Inc.
G1 Therapeutics, Inc. is a privately held clinical-stage pharmaceutical company based in Research Triangle Park, NC that focuses on the discovery and development of novel small-molecule therapies to address significant unmet needs in oncology. The company is leveraging its proprietary kinase drug discovery platform to advance a pipeline of first-in-class compounds and best-in-class drug candidates that address two markets: CDK4/6 antineoplastics and protection of the bone marrow from damage by chemotherapy (chemoprotection). The company's lead program, G1T28, is a highly potent and selective CDK4/6 inhibitor that is currently being evaluated in Phase 1a clinical trials.

Visit www.g1therapeutics.com for more information.

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Contact:                                                              
Mark Velleca, MD, PhD                
G1 Therapeutics                                              
919-213-9838                                                    
mvelleca@g1therapeutics.com                  

Media:
Laura Bagby                     
6 Degrees Communications
312-448-8098
lbagby@6degreespr.com