Background: This pivotal phase III trial evaluated the efficacy and safety of palonosetron in preventing acute and delayed chemotherapy-induced nausea and vomiting (CINV) following highly emetogenic chemotherapy (HEC).
Patients and methods: Patients were randomized to a single intravenous dose of palonosetron 0.25 mg or 0.75 mg, or ondansetron 32 mg prior to HEC. Dexamethasone pre-treatment (with stratification) was used at investigator discretion. The primary efficacy endpoint was the proportion of patients with complete response (CR) during the first 24 h post-chemotherapy (acute phase).
Results: In the intent-to-treat analysis (n = 667), palonosetron 0.25 mg and 0.75 mg were at least as effective as ondansetron in preventing acute CINV (59.2%, 65.5%, and 57.0% CR rates, respectively); CR rates were slightly higher with palonosetron than ondansetron during the delayed (24-120 h) and overall (0-120 h) phases. Two thirds of patients (n = 447) received concomitant dexamethasone. Patients pre-treated with palonosetron 0.25 mg plus dexamethasone had significantly higher CR rates than those receiving ondansetron plus dexamethasone during the delayed (42.0% versus 28.6%) and overall (40.7% versus 25.2%) phases. Palonosetron and ondansetron were well tolerated.
Conclusions: Single-dose palonosetron was as effective as ondansetron in preventing acute CINV following HEC, and with dexamethasone pre-treatment, its effectiveness was significantly increased over ondansetron throughout the 5-day post-chemotherapy period.