G1 Therapeutics provides update on Phase 3 PRESERVE 2 trial of trilaciclib

G1 Therapeutics announced topline results from the final OS analysis of its Phase 3 PRESERVE 2 trial evaluating the efficacy and safety of trilaciclib administered prior to chemotherapy in patients with metastatic TNBC. The study did not demonstrate a statistically significant treatment effect in the ITT population with a hazard ratio of 0.91. The median OS in the trilaciclib plus GCb arm was 17.4 months compared to 17.8 months in the control arm. Median OS numerically favored the trilaciclib arm in both PD-L1 subgroups (positive and negative), though neither achieved statistical significance. Varying effects were observed across regions and patients who received different types of subsequent therapies; these findings will be evaluated further. The safety profile of trilaciclib with GCb observed in the trial was consistent with prior studies, and no new safety signals were identified. Consistent with other trilaciclib studies, evidence of myeloprotection was observed, including a reduction in the occurrence of severe neutropenia, which occurred in 8% of patients who received trilaciclib compared to 29% of patients in the control arm. The company will submit the results of this trial to a future medical conference. “The unexpected results from PRESERVE 2 underscore the challenge of developing new therapies for triple negative breast cancer,” said Jack Bailey, CEO of G1 Therapeutics. “We are disappointed that this trial did not deliver the benefit that we anticipated to people living with TNBC. We are also grateful to the patients who participated in this trial, their families, and their healthcare teams including the clinicians and their staff.” Bailey continued, “We will now further our focus on both accelerating and expanding the growth of the ES-SCLC business to achieve anticipated company profitability in the second half of 2025 and evaluating other myeloprotection uses for trilaciclib. We are also pursuing ex-US partners to expand the use of COSELA globally.”