Fourteen RCTs (6,467 patients) were included.
Acute nausea and vomiting. No significant differences were found between granisetron and ondansetron for any of the outcomes. Significant heterogeneity was only found for those studies assessing acute vomiting induced by moderately emetogenic chemotherapy (p=0.03). After exclusion of the one RCT significantly favouring one drug, heterogeneity was no longer significant (p=0.11) and a similar, non significant pooled RR was found.
Acute vomiting induced by highly emetogenic chemotherapy: the RR was 1.06 (95% CI: 0.97, 1.14).
Acute nausea induced by highly emetogenic chemotherapy: the RR was 1.00 (95% CI: 0.93, 1.08).
Acute vomiting induced by moderately emetogenic chemotherapy: the RR was 0.99 (95% CI: 0.86, 1.14).
Acute nausea induced by moderately emetogenic chemotherapy: the RR was 0.97 (95% CI: 0.88, 1.07).
Delayed nausea and vomiting. No significant differences were found between granisetron and ondansetron for any of the outcomes. There was no evidence of significant statistical heterogeneity. Delayed vomiting induced by highly emetogenic chemotherapy: the RR was 1.00 (95% CI: 0.86, 1.14).
Delayed nausea induced by highly emetogenic chemotherapy: the RR was 1.08 (95% CI: 0.96, 1.22).
Delayed vomiting induced by moderately emetogenic chemotherapy: the RR was 1.02 (95% CI: 0.94, 1.12).
Delayed nausea induced by moderately emetogenic chemotherapy: the RR was 1.00 (95% CI: 0.93, 1.08).
Toxicity.
Only one study reported a significant difference in toxicity between the drugs: significantly more patients reported dizziness and blurred vision in the ondansetron arm than in the granisetron arm.
The authors reported that their review had several limitations: the number of studies and eligible patients were heterogeneous within the different outcomes; for some outcomes, the meta-analysis had a power of only 40% to detect a 5% difference in efficacy.