QTc prolongation across CDK4/6 inhibitors: a systematic review and meta-analysis of randomized controlled trials.

ABSTRACT

BACKGROUND: Cyclin-dependent kinases (CDK) 4/6 inhibitors have significantly improved outcomes for patients with ER+/HER2- breast cancer. Nevertheless, they differ from each other in terms of chemical, biological, and pharmacological features, as well as toxicity profiles. We aim to determine whether QTc prolongation is caused by CDK4/6i in general or if it is associated with ribociclib only. METHODS: We systematically searched PubMed, Embase, and Cochrane Library for randomized controlled trials (RCTs) comparing the prevalence of QTc prolongation as an adverse event in HR+ breast cancer patients treated with CDK4/6i vs those without CDK4/6i. We pooled risk ratio (RR) and mean difference (MD) with 95% confidence interval (CI) for the binary endpoint of QT prolongation. RESULTS: We included 14 RCTs comprising 16,196 patients, of whom 8,576 underwent therapy with CDK4/6i. An increased risk of QTc prolongation was associated with the use of CDK4/6i (RR 2.35; 95% CI 1.67-3.29; p < .001; I2=44%). Subgroup analyses revealed a significant increase in the QTc interval for the ribociclib and palbociclib cohorts. The ribociclib subgroup showed a risk ratio of 3.12 (RR 3.12; 95% CI 2.09-4.65; p < .001; I2 = 12%) while the palbociclib subgroup had a risk ratio of 1.51 (RR 1.51; 95% CI 1.05-2.15; p = .025, I2=0%). CONCLUSION: Palbociclib was associated with QTc prolongation, however, the RR for any grade QTc was quantitively twice with ribociclib. Furthermore, grade 3 QTc prolongations were observed exclusively with ribociclib. These results are important for guiding clinical decision-making and provide reassurance regarding the overall safety profile of this drug class.