Impact of trilaciclib on multilineage chemotherapy-induced myelosuppression events in patients with extensive-stage small cell lung cancer: Post-hoc analyses of data from randomized clinical trials.

Abstract

8568 Background: Trilaciclib is a short-acting CDK4/6 inhibitor administered prior to chemotherapy for multilineage myeloprotection. Reduced occurrence of chemotherapy-induced myelosuppression (CIM) events across neutrophil, red blood cell, and platelet lineages was reported in 3 Phase 2 clinical trials of trilaciclib versus placebo in patients with extensive-stage small cell lung cancer (ES-SCLC). In this post-hoc trial analysis, we further assessed the impact of trilaciclib on the occurrence of single and concurrent multilineage CIM events. Methods: Analyses were conducted separately by line of chemotherapy. In the first-line (1L) setting, pooled data from the G1T28-05 and G1T28-02 trials, in which trilaciclib or placebo was administered prior to etoposide, carboplatin, and atezolizumab [E/P/A] and E/P, respectively, were used. In the 2/3L setting, analyses were based on data from the G1T28-03 trial where patients received trilaciclib or placebo prior to topotecan. The proportion of patients with single and concurrent multilineage CIM events and incidence rate were estimated per cycle and during the first 4 cycles of chemotherapy. Severe (grade ≥ 3 per CTCAE definition) CIM events of neutropenia (SN), anemia (SA), and thrombocytopenia (ST) were assessed. Concurrent CIM events were defined as having 2 or 3 lineage-specific CIM events overlap for ≥ 1 day. As sensitivity analyses, the occurrence of CIM events in patients with ES-SCLC receiving 1L treatment in the G1T28-05 and G1T28-02 studies was analyzed separately. Results: Compared with placebo, fewer patients receiving trilaciclib had single-lineage CIM events and concurrent events in 2 or 3 lineages during cycles 1–4 of 1L chemotherapy using pooled data from G1T28-05 and G1T28-02 (Table). A similar trend was observed in the 2/3L setting. Generally, SN occurred more frequently in earlier cycles, whereas SA and ST tended to occur later. The sensitivity analysis in each individual 1L trial yielded consistent results with the pooled analysis. Conclusions: Patients with ES-SCLC receiving trilaciclib prior to chemotherapy had fewer single and concurrent multilineage CIM events than patients receiving placebo. Clinical trial information: NCT03041311, NCT02499770, NCT02514447. [Table: see text]