June 24 (Reuters) - G1 Therapeutics said on Monday its drug for a rare, aggressive form of breast cancer did not meet the main goal of overall survival in a late-stage trial.

G1's drug trilaciclib was tested in 187 patients with metastatic triple-negative breast cancer, with the patients who took the drug showing a median overall survival of 17.4 months, while patients who did not receive the treatment survived for 17.8 months overall.

CEO Jack Bailey said G1 will evaluate other uses for trilaciclib and will pursue partners to expand its use globally

Last week, AstraZeneca's breast cancer drug, Truqap, in combination with chemotherapy agent paclitaxel, did not meet its main goals in a late-stage trial to improve overall survival of patients.

Shares of G1 therapeutics fell 31.8% in premarket trading. (Reporting by Christy Santhosh; Editing by Tasim Zahid)