ESMO: Oral Palonosetron Prevents CINV over Multiples Cycles of MEC
Currently, palonosetron is approved by the US Food and Drug Administration for the prevention of CINV in the intravenous dosage of 0.25mg and in the oral dosage of 0.50mg, with a demonstrated comparable clinical effect of the two formulations.
In the multicenter, open-label study, 217 patients enrolled in 22 study centers in the United States, Europe, and Mexico received a single dose of oral palonosetron 0.75mg 60 minutes prior to MEC for a maximum of 4 consecutive cycles “to best evaluate the safety of the oral formulation of multiple cycles of chemotherapy,” noted Steven Grunberg, MD, of the University of Vermont, Burlington, VT.
At investigator discretion, concomitant administration of dexamethasone 8mg on treatment day 1 was allowed.
The patients, who were 75% female, 61% white, 36% Hispanic, and 66% chemotherapy-naïve, received 654 cycles of MEC (median 3 cycles); approximately half received 4 cycles. Concomitant dexamethasone was administered in 483 cycles and palonosetron was given alone in 171 cycles.
Generally, antiemetic efficacy was maintained across the chemotherapy cycles. Overall complete response (CR) rates (i.e., no emesis and no need for rescue medication) ranged from 55% to 60% of patients over the 3-4 cycles. Higher CR rates were observed when dexamethasone was given concomitantly vs palonosetron alone (acute CINV: 74% vs 61%; delayed CINV: 63% vs 60% respectively, all cycles combined).
The majority of adverse events (AEs) were mild. The most commonly observed AE in 3.5% of cycles of palonosetron alone and 5.4% of cycles of palonosetron plus dexamethasone was headache. In both groups, AEs decreased from cycle 1 to 3 and remained about the same for cycle 4. Few severe or serious AEs were noted and raised no safety concerns.
Dr. Grunberg is an Helsinn Healthcare consultant.