Three palonosetron regimens to prevent CINV in myeloma patients receiving multiple-day high-dose melphalan and hematopoietic stem cell transplantation

Background: Explore safety and efficacy of three palonosetron-containing regimens for emesis prevention over 7 days in multiple myeloma (MM) patients receiving melphalan (100 mg/m²) and hematopoietic stem cell transplantation (HSCT). Patients and methods: Randomized, double-blind pilot study in MM patients (n = 73) receiving 1, 2, or 3 days of 0.25 mg palonosetron (30-s i.v. bolus) 30 min before melphalan (days 22 and 21) and HSCT (day 0). Patients received dexamethasone (20 mg i.v., days 22 and 21) immediately before or after study drug/placebo. Daily diaries recorded emesis, rescue medication, nausea duration, and adverse events (AEs). Results: Seven-day complete protection (no emesis) occurred in 41.7% [95% confidence interval (CI) 22.1% to 63.4%], 41.7% (95% CI 22.1% to 63.4%), and 44.0% (95% CI 24.2% to 65.1%) of patients receiving 1, 2, or 3 days of palonosetron, respectively (P = 0.43). Complete response (emesis free without rescue medication) occurred in 8.3%, 20.8%, and 20.0% (P = 0.14). Common AEs (≥10%) were mild-to-moderate diarrhea, constipation, headache, insomnia, and flatulence. No serious AEs occurred. Conclusions: Palonosetron with dexamethasone was safe and effective in preventing emesis in MM patients receiving melphalan and HSCT. This pilot study with a limited number of patients suggests that multiple doses of palonosetron could be more effective than a single dose in making patients emesis free without need for rescue medication. However, even multiple doses of palonosetron resulted in only 20% of patients being emesis free without rescue medication, suggesting that further improvement will require development of more effective combination antiemetic therapy.