Netupitant/palonosetron is effective for preventing chemotherapy-induced nausea and vomiting in high-dose melphalan conditioning before autologous stem cell transplantation: A real-world analysis

High-dose melphalan (HDM) is the standard conditioning regimen before autologous stem cell transplantation (ASCT) in plasma cell malignancies. Despite prophylactic antiemetics, chemotherapy-induced nausea and vomiting (CINV) remains a prevalent challenge. We retrospectively compared the efficacy of netupitant and palonosetron (NEPA) plus dexamethasone with that of serotonin receptor antagonist (5-HT₃RA)-based regimens (the control group) for patients receiving HDM. The primary endpoint was complete resolution (CR) of CINV in the acute (0-24 hours) and delayed (24-168 hours) phases. Secondary endpoints included overall response rate (ORR), subgroup benefit, and nutritional outcomes. In total, 108 patients were included (NEPA, n = 38; control, n = 70). The NEPA group exhibited higher CR rates in both acute (65.8% vs 32.9%; <i>p</i> < 0.010) and delayed phases (50.0% vs 12.9%; <i>p</i> < 0.010). NEPA achieved a higher ORR (73.7% vs 24.3%; <i>p</i> < 0.010). Subgroup analysis indicated consistent benefits across most clinical strata. Multivariable analysis identified NEPA and male gender as independent factors predicting CR. The median duration of parenteral nutrition (PN) was shorter in the NEPA group than in the control group (median, 2 days [range 1-2] vs 3 days [range, 3-5.75]; <i>p</i> = 0.046). Compared to standard 5-HT₃RA regimens, NEPA significantly improved antiemetic efficacy in patients undergoing HDM conditioning.