G1T48 is a proprietary, orally available, selective estrogen receptor degrader (SERD).  Preclinical data presented at the American Association for Cancer Research 2017 Annual Meeting demonstrated G1T48 to be more potent than Faslodex® and to have superior anti-tumor efficacy versus other SERDs in development. A Phase 1 trial of G1T48 in estrogen receptor-positive, HER2-negative (ER+, HER2-) breast cancer is expected to initiate in 2Q18.

There is strong scientific rationale and clinical validation supporting the combination of a CDK4/6 inhibitor and a SERD for the treatment of patients with ER+, HER2- breast cancer. G1 is planning to combine G1T38 and G1T48 as an all-oral, potentially best-in-class regimen in this indication.