G1 Therapeutics, Inc. announced new clinical, commercial and corporate updates, including encouraging preliminary overall survival (OS) data from the Company's ongoing Phase 2 trial of trilaciclib in combination with the ADC sacituzumab govitecan (SG) in patients with TNBC. This update is now available in a new corporate presentation which will be used during the 42nd Annual J.P. The update includes the following: Clinical: Initial efficacy results from ongoing Phase 2 ADC trial suggest improved OS among patients receiving trilaciclib in combination with a TROP2 ADC: Preliminary data from the ongoing Phase 2 trial of trilaciclib in combination with the ADC sacituzumab govitecan (SG) in metastatic TNBC patients suggests clinically meaningful improvements in OS among patients receiving trilaciclib in combination with SG compared to SG alone based on historical data from the ASCENT trial, including (1) current median OS of 17.9 months with trilaciclib vs 12.1 months for SG alone and (2) estimated 12-month survival of 59% of patients receiving trilaciclib in combination with SG, which would be a ~20% improvement over SG alone. The Company expects to provide updated OS data from this study mid-2024.

Interim OS analysis of ongoing 1L TNBC pivotal trial expected in first quarter 2024: This Phase 3 trial builds upon the clinically meaningful and statistically significant OS results demonstrated in the previous Phase 2 TNBC trial. Achievement of the OS endpoint would enable global regulatory submissions. OS continues to improve over time for Phase 2 TNBC patients receiving subsequent anti-cancer therapy (SACT): Among patients receiving SACT after conclusion of study drug in the previous Phase 2 TNBC trial, the OS benefit in the trilaciclib arm increased over time as patients received SACT.

Patients in the trilaciclib arms receiving subsequent 2L+ chemotherapy exhibited a median OS of 14.0 months from start of SACT, compared to patients in the chemotherapy arm receiving subsequent 2L+ chemotherapy of 5.8 months (p=0.001). The median OS of 14.0 months in the trilaciclib arms also compares favorably to historical 2L+ benchmarks for chemotherapy and SG of 6.7 months and 12.1 months in the ASCENT trial, respectively.