Prevention of delayed nausea and vomiting (D-CINV): Carryover effect analysis of pooled data from 2 phase III studies of palonosetron (PALO)

8051 Background: Control of acute chemotherapy-induced nausea and vomiting (A-CINV) is a positive predictor of control of D-CINV. First-generation 5-HT3 receptor antagonists (RA) are highly effective in preventing A-CINV but less so in preventing D-CINV. PALO is a pharmacologically distinct 5-HT3 RA with a 30+ fold higher binding affinity, a 40 hr plasma half-life, and has greater efficacy than ondansetron (OND) and dolasetron (DOL) in preventing both A-CINV and D-CINV in patients receiving moderately emetogenic chemotherapy (Aapro, ASCO '03, Rubenstein ASCO '03). Methods: Establishing whether this efficacy benefit in control of D-CINV is strictly a carryover effect from better control of A-CINV was analyzed using pooled data from 2 identically designed phase III trials where 754 patients received either a single IV dose of 0.25 mg PALO or 32 mg OND (study 1) or 100 mg DOL (study 2). Two methods for evaluating the carryover effect were conducted: evaluating control of D-CINV in all patients with or withou...