Efficacy of a single intravenous dose of palonosetron HCl in preventing acute and delayed nausea and vomiting induced by both moderately and highly emetogenic chemotherapy was studied in 4 trials. In these double-blind studies, complete response rates (no emetic episodes and no rescue medication) and other efficacy parameters were assessed through at least 120 hours after administration of chemotherapy. The safety and efficacy of palonosetron HCl in repeated courses of chemotherapy was also assessed.

Moderately Emetogenic Chemotherapy

Two double-blind trials (Study 1 and Study 2) involving 1132 patients compared a single intravenous dose of palonosetron HCl with either a single intravenous dose of ondansetron (Study 1) or dolasetron (Study 2) given 30 minutes prior to moderately emetogenic chemotherapy including carboplatin, cisplatin ≤ 50 mg/m2, cyclophosphamide <1500 mg/m2, doxorubicin > 25 mg/m2, epirubicin, irinotecan, and methotrexate >250 mg/m2. Concomitant corticosteroids were not administered prophylactically in Study 1 and were only used by 4 to 6% of patients in Study 2. The majority of patients in these studies were women (77%), White (65%) and naïve to previous chemotherapy (54%). The mean age was 55 years.

Highly Emetogenic Chemotherapy

A double-blind, dose-ranging trial evaluated the efficacy of a single intravenous dose of palonosetron HCl from 0.3 to 90 mcg/kg (equivalent to < 0.1 mg to 6 mg fixed dose) in 161 chemotherapy-naïve adult cancer patients receiving highly-emetogenic chemotherapy (either cisplatin ≥ 70 mg/m2 or cyclophosphamide > 1100 mg/m2). Concomitant corticosteroids were not administered prophylactically. Analysis of data from this trial indicates that 0.25 mg is the lowest effective dose in preventing acute nausea and vomiting induced by highly emetogenic chemotherapy.

A double-blind trial involving 667 patients compared a single intravenous dose of palonosetron HCl with a single intravenous dose of ondansetron (Study 3) given 30 minutes prior to highly emetogenic chemotherapy including cisplatin ≥ 60 mg/m2, cyclophosphamide > 1500 mg/m2, and dacarbazine. Corticosteroids were co-administered prophylactically before chemotherapy in 67% of patients. Of the 667 patients, 51% were women, 60% White, and 59% naïve to previous chemotherapy. The mean age was 52 years.

Efficacy Results

The antiemetic activity of palonosetron HCl was evaluated during the acute phase (0-24 hours) [Table 4], delayed phase (24-120 hours) [Table 5], and overall phase (0-120 hours) [Table 6] post-chemotherapy in Studies 1, 2 and 3.

These trials show that palonosetron HCl was effective in the prevention of acute nausea and vomiting associated with initial and repeat courses of moderately and highly emetogenic cancer chemotherapy. In Study 3, efficacy was greater when prophylactic corticosteroids were administered concomitantly. Clinical superiority over other 5-HT3 receptor antagonists has not been adequately demonstrated in the acute phase.

These trials show that palonosetron HCl was effective in the prevention of delayed nausea and vomiting associated with initial and repeat courses of moderately emetogenic chemotherapy.

These trials show that palonosetron HCl was effective in the prevention of nausea and vomiting throughout the 120 hours (5 days) following initial and repeat courses of moderately emetogenic cancer chemotherapy.