Palonosetron plus 1-day dexamethasone for the prevention of nausea and vomiting due to moderately emetogenic chemotherapy: effect of established risk factors on treatment outcome in a phase III trial.

BACKGROUND: The non-inferiority of palonosetron plus 1-day versus 3-day dexamethasone in preventing chemotherapy-induced nausea and vomiting (CINV) due to moderately emetogenic chemotherapy (MEC) has been previously demonstrated. OBJECTIVE: The objectives of this prespecified post hoc analysis were to demonstrate the non-inferiority hypothesis in an adjusted model for known risk factors (age, gender, alcohol consumption, and type of MEC [anthracycline plus cyclophosphamide (AC)-based versus other MEC]) for CINV and to explore the impact on antiemetic outcome of these risk factors. METHODS: Chemonaive patients (n = 324) with solid tumors were randomized to receive palonosetron 0.25 mg IV plus dexamethasone 8 mg IV on day 1 of chemotherapy or the same regimen followed by oral dexamethasone 8 mg on days 2 and 3. The primary end point was complete response (CR, no emesis and no rescue antiemetics) during the 5-day study period. A modified intention-to-treat approach was used for multivariable analysis. RESULTS: Non-inferiority of the 1-day regimen was confirmed even after adjusting for risk factors (risk difference -4.4%, 95% CI -14.1% to 5.4%; P = .381). Only age less than 50 years (P = .044) independently predicted a poor outcome of antiemetic treatment. However, most of the younger patients were women (1-day regimen 81.8%, 3-day regimen 88.4%) who underwent AC-based chemotherapy (1-day regimen 61.1%, 3-day regimen 71.0%). There were no significant between-treatment differences in the CR rate according to risk factors. CONCLUSION: This analysis confirmed that the 1-day regimen provides a valid treatment option for prevention of CINV in delayed, non-AC-based MEC.