Trilaciclib use for prevention of hematological adverse events in chemotherapy: A meta-analysis of real-world studies and clinical trials

Background: Trilaciclib, a cyclin-dependent kinase (CDK)-4 and -6 inhibitor, is the only FDA-approved agent that preemptively protects hematopoietic stem cells from chemotherapy-induced myelosuppression (CIM) without compromising efficacy. It transiently arrests hematopoietic stem cells in the G1 phase, thus temporarily blocking progression through the cell cycle and protecting progenitor cells from cytotoxicity. It has been approved for use in extensive-stage small-cell lung cancer (SCLC). Limited real-world evidence of its efficacy exists owing to its recent approval. We sought to enhance our understanding and evaluate the preventive effect of trilaciclib through a combined meta-analysis of clinical trials and retrospective studies.

Methods: A systematic literature search was performed on PubMed, Embase, Cochrane, and Scopus from inception until December 2023. Retrospective cohort studies and randomized-controlled trials with trilaciclib and non-trilaciclib arms were included. The primary outcomes of interest were CIM-related grade ≥3 hematological adverse events, and secondary outcomes included supportive care interventions to remedy CIM. Quantitative meta-analyses were conducted using the random-effects model on STATA v17.

Results: The meta-analysis comprised seven studies, including four clinical trials and three real-world retrospective studies, including 6537 patients with extensive SCLC or locally recurrent or metastatic breast cancer. Chemotherapy regimens in SCLC patients included the combination of etoposide/platinum (E/P), E/P/PD-L1 inhibitors, or topotecan, and gemcitabine/carboplatin in patients with breast cancer. The mean age of the patients was 63.28 ± 5.31 years, and 49.21% were males. Administration of trilaciclib led to a reduction in the incidence of febrile neutropenia (2.41% vs. 7.56% OR = 0.35), severe neutropenia (21.76% vs. 41.91% OR = 0.57), anemia (18.02% vs. 32.41% OR = 0.51), and thrombocytopenia (20.06% vs. 31.25% OR = 0.62). Utilization of cytopenia-supportive therapies, including granulocyte colony-stimulating factor use (40.47% vs. 81.01% OR = 0.61) and RBC transfusions (16.66% vs. 18.25% OR = 0.59) were significantly lower in the trilaciclib cohort as compared to control. The overall response rate (mean difference = 1.09,95% CI = 0.74–1.60) and overall survival (OR = -0.02 95% CI = -0.95-0.92) were similar, and progression-free survival was noted to be longer in the trilaciclib group (mean difference = 1.75, 95% CI = 0.75-2.75).

Conclusions:Trilaciclib use consistently demonstrated efficacy in reducing CIM, thus lowering cytopenia-related healthcare utilization without compromising treatment efficacy in trials and real-world settings. Its novel mechanism of action offers great promise, and further studies with larger sample sizes on various cancers will corroborate existing evidence.

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