1998P - Antitumor activity and safety profile of trilaciclib in Chinese patients with extensive-stage small cell lung cancer (ES-SCLC) receiving chemotherapy (TRACES): Updated results from TRACES

Background

Trilaciclib, a potent and reversible intravenous CDK4/6 inhibitor, has been approved by US FDA and China NMPA to prevent multilineage chemotherapy-induced myelosuppression in ES-SCLC patients. The TRACES study is a phase III trial assessing the efficacy and safety of trilaciclib in Chinese ES-SCLC patients. The bone marrow protection effect was significant which was reported in WCLC 2022.

Methods

This study included an open-label safety run-in part (Part 1) and a randomized, double-blinded, placebo-controlled part (Part 2). Treatment-naïve or previously treated ES-SCLC patients received trilaciclib (240 mg/m²) or placebo before etoposide/cisplatin (E/P) or topotecan (TPT) respectively. The primary endpoint is the duration of severe neutropenia in Cycle 1. The exploratory endpoints for anti-tumor effect are OS and ORR, PFS and DOR assessed by RECIST v1.1.

Results

As of 30 December 2022, a total of 83 patients were enrolled in Part 2, with 41 receiving trilaciclib (E/P: 23; TPT:18) and 42 receiving placebo (E/P: 23; TPT:19). The mean number of cycles were 5.1 and 4.6 cycles in trilaciclib and placebo group (E/P: 5.0 vs 4.9 cycles; TPT: 5.3 vs 4.3 cycles). Compared with placebo group, trilaciclib group had fewer cycle delays (E/P: 30.4% vs 73.9%; TPT: 44.4% vs 73.7%) and dose reductions (E/P: 30.4% vs 73.9%; TPT: 44.4% vs 73.7%). The ORR in trilaciclib group and placebo group were 44.7% and 39.5% (p=0.4996) respectively. After a median follow-up of 14.1 months, the median overall survival was 12.0 months in the trilaciclib group and 8.8 months in the placebo group (hazard ratio [HR], 0.69; 95% confidence interval [CI], 0.40 to 1.22). The median progression-free survival was 4.8 months and 4.3 months, respectively (HR, 0.86; 95% CI, 0.53 to 1.39). Trilaciclib was well tolerated, with lower incidence of ≥Grade 4 TEAEs, SAEs, TEAEs leading to treatment discontinuation. No TEAEs leading to death were reported related to trilaciclib.

Conclusions

Trilaciclib was well tolerated in Chinese patients. Administering trilaciclib prior to chemotherapy in ES-SCLC patients improved patients’ tolerability to chemotherapy, and suggested potential survival benefit.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Nanjing Zaiming Pharmaceutical Co., Ltd.

Funding

Nanjing Zaiming Pharmaceutical Co., Ltd.

Disclosure

All authors have declared no conflicts of interest.