Evaluation of palonosetron, fosaprepitant, and olanzapine as antiemetic prophylaxis for fludarabine and melphalan-based conditioning regimens prior to allogeneic hematopoietic stem cell transplants

Limited data are available regarding efficacious antiemetic regimens to prevent chemotherapy-induced nausea and vomiting (CINV) for patients undergoing allogeneic hematopoietic stem cell transplant (HSCT). In patients aged 60 years or older, allogeneic HSCT is associated with improved survival, but tolerability of the transplant is a significant barrier. Fludarabine and melphalan (Flu–Mel) is a frequently utilized multi-day reduced intensity conditioning regimen for allogeneic HSCT. However, the optimal CINV prevention regimen is unknown. The purpose of this study was to evaluate the efficacy of a novel CINV prophylaxis regimen prior to allogeneic HSCT with Flu–Mel compared to a historical control group. This was a retrospective, single-center, cohort review of 123 patients who received a Flu–Mel preparative regimen prior to allogeneic HSCT from January 1, 2019, to September 30, 2022. Fifty-nine patients received high dose ondansetron (HDO) for CINV prevention, while sixty-four patients received a combination of palonosetron, fosaprepitant, and olanzapine (PFO). The primary outcome was average number of rescue antiemetic doses administered per day. A key secondary outcome was time to first rescue antiemetic. The median number of antiemetic doses used per day was significantly lower in patients who received PFO compared to HDO (1.94 doses [0.31–3.60] vs 3.31 doses [1.61–4.92]; p = 0.002). In addition, use of PFO significantly prolonged the median time to first rescue antiemetic compared to HDO (41.3 h [24.3–122.7] vs 26.2 h [14.7–48.1]; p = 0.016). The combination of palonosetron, fosaprepitant, and olanzapine is an effective antiemetic regimen for patients receiving a Flu–Mel-based preparative regimen.