Network meta-analysis compares 5-HT3 antagonists with or without dexamethasone for highly emetogenic chemotherapy-induced nausea and vomiting.

This study is a network meta-analysis comparing the comparative efficacy of 5-hydroxytryptamine-3 (5-HT3) receptor antagonists with or without dexamethasone for preventing chemotherapy-induced nausea and vomiting (CINV) following highly emetogenic chemotherapy (HEC). The analysis incorporated data from randomized controlled trials involving a total sample size of 11,131 patients. The specific setting of the included trials was not reported. The interventions evaluated included palonosetron, ondansetron, granisetron, tropisetron, and ramosetron, administered either as monotherapy or in combination with dexamethasone. The primary outcome was not explicitly reported in the provided data, though secondary outcomes covered acute and delayed nausea, vomiting, and complete control.

regarding delayed vomiting outcomes, the analysis indicated that palonosetron is more effective than ondansetron, with a relative risk (RR) of 1.47 and a 95% confidence interval [1.03-2.08]. When comparing combination therapies, palonosetron plus dexamethasone was superior to ondansetron plus dexamethasone, showing an RR of 1.35 (95% CI [1.14-1.60]). Similarly, palonosetron plus dexamethasone demonstrated superiority over granisetron plus dexamethasone, with an RR of 1.52 (95% CI [1.22-1.91]). For acute vomiting, palonosetron plus dexamethasone was superior to ondansetron plus dexamethasone, with an RR of 0.81 (95% CI [0.69-0.96]).

key secondary outcomes included acute nausea, acute vomiting, acute complete control, delayed nausea, delayed vomiting, and delayed complete control. The results highlighted that adding dexamethasone to palonosetron showed no significant advantage over palonosetron alone in any outcome measure in indirect comparisons. Additionally, no significant efficacy differences were observed between palonosetron plus dexamethasone and tropisetron plus dexamethasone, or ramosetron plus dexamethasone. No significant differences were observed between palonosetron and one 5-HT3 antagonist plus dexamethasone in these indirect comparisons.

Safety and tolerability findings were not reported in the available data. Adverse events, serious adverse events, discontinuations, and general tolerability profiles were not detailed. Consequently, a comprehensive assessment of the safety profile for these specific regimens cannot be derived from this summary alone.

Methodological limitations include the reliance on indirect comparisons for some of the efficacy analyses. The study phase was not reported, and the specific setting of the included trials remains unclear. The authors note that further studies are needed between palonosetron plus dexamethasone and tropisetron plus dexamethasone or ramosetron plus dexamethasone. Similarly, further studies are required between palonosetron monotherapy and one 5-HT3 antagonist plus dexamethasone to clarify these relationships.

Clinical implications suggest that while palonosetron-based regimens appear more effective than ondansetron or granisetron combinations for delayed vomiting, the evidence is based on indirect comparisons. Practitioners should interpret these findings with caution, recognizing the association derived from a network meta-analysis rather than direct head-to-head trials. The lack of reported safety data limits the ability to weigh risks against benefits for specific patient populations.

Several questions remain unanswered. The specific setting of the trials limits the generalizability of the findings to different healthcare environments. The absence of safety data prevents a full risk-benefit analysis. Furthermore, the lack of significant differences between palonosetron plus dexamethasone and other 5-HT3 antagonists plus dexamethasone raises questions about the necessity of adding dexamethasone to palonosetron in all cases. Future research should aim to address these gaps with direct comparative trials and comprehensive safety reporting.