Comparison of palonosetron (PALO) plus dexamethasone on day 1, with or without dexamethasone on days 2 and 3, in the prevention of chemotherapy induced nausea and vomiting (CINV) in breast cancer patients treated with anthracycline/cyclophosphamide regimens.

Abstract #4088 BACKGROUND PALO is a selective and potent serotonin antagonist, with a pharmacologically different structure and binding affinity compared to older 5-HT3 receptors antagonists. Multiple studies with PALO have demonstrated better efficacy in preventing emesis throughout the 5 days after moderately and highly emetogenic chemotherapy (CT) compared to ondansetron, dolasetron or granisetron.
 METHODS This was a phase 4, double-blind, randomized, multicenter, parallel study, in 300 CT naive patients with breast cancer receiving cyclophosphamide 2 or anthracycline (epirubicin or doxorubicin) alone or in combination. The study aimed to determine whether the efficacy during the 0-120 hr (overall) period after CT, of a PALO single-dose 0.25mg IV administered 30 minutes before CT plus dexamethasone 8 mg IV approximately 1 hr before CT on day 1 (PALO/DEX/Placebo), was non-inferior to the same day 1 regimen followed by DEX 4 mg orally twice daily on days 2 and 3 (PALO/DEX/DEX). The primary endpoint was complete response (CR), defined as no emesis and no rescue therapy, in the overall phase. Emesis, nausea, use of rescue antiemetics, and functional impact were secondary endpoints. Adverse events (AEs) were documented to monitor safety.
 RESULTS This study showed non-inferiority in CR rates between the two groups in the overall phase, and in the acute and delayed phases (Table I).
 There were no significant differences between groups for no emesis and no nausea rates. Rates of AEs were similar in the two groups, with no serious drug-related AEs reported.
 CONCLUSIONS The comparable results between the two groups support the efficacy of PALO plus DEX administration on day 1 only, with no benefit shown for additional doses of dexamethasone. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4088.