Despite the availability of several antiemetics, clinical findings show that control of chemotherapy-induced nausea and vomiting (CINV) continues to be a serious concern for hematological patients, mainly for those receiving multiple-day (MD) and high-dose (HD) chemotherapy (CT). For CINV prophylaxis, 5-hydroxytryptamine type-3 receptor antagonists (5HT3-RAs) and neurokinin 1 receptor antagonists (NK1-RAs) are usually administered together with dexamethasone, which may increase the risk of serious infections in patients undergoing myeloablative treatment. The rationale of this multicenter, open-label and phase IIa study was to explore the efficacy of multiple doses of NEPA (netupitant/palonosetron) given as an every-other-day regimen without dexamethasone in preventing CINV in patients with relapsed-refractory aggressive non-Hodgkin's lymphoma (R/R-NHL), eligible for autologous stem cell transplantation (ASCT) and treated with MD-HD-CT. Seventy patients participated to the study. According to the adopted Fleming one-stage design, the primary endpoint of this study was achieved. The CR values were 87.1% (primary endpoint, overall phase: days 1-8), 88.6% (acute phase: days 1-6), and 98.6% (delayed phase: days 7-8), while complete control (CR with no more than mild nausea) was 85.7% (overall phase), 88.6% (acute phase), and 95.7% (delayed phase). Moderate and severe episodes of nausea were reported by less than 10% of patients in the overall phase and less than 5% in both the acute and delayed phases. Regarding safety, NEPA was well tolerated with only one adverse event (constipation) evaluated as possibly related to NEPA administration. In conclusion, our study demonstrated that multiple alternate dosing of NEPA without the addition of dexamethasone is highly effective for preventing nausea and vomiting in this difficult setting, with a good tolerability profile.