 G1 Therapeutics Inc NASDAQ: GTHX shares gain premarket after FDA approves COSELA trilaciclib for injection to decrease the incidence of chemotherapy-induced myelosuppression damage to bone marrow in adult patients when administered before a platinumetoposide-containing regimen or topotecan-containing regimen for extensive-stage small-cell lung cancer. COSELA is administered intravenously as a 30-minute infusion within four hours before the start of chemotherapy. 