Background. Neurokinin (NK) 1 receptor antagonists (RA), administered in combination with a 5-HT 3 RA and dexamethasone (DEX), have demonstrated clear improvements in CINV prevention over a 5-HT 3 RA plus DEX. However, studies comparing the NK 1 RAs in the class are lacking. NEPA, a fixed combination of a highly selective NK 1 RA, netupitant, and the 5-HT 3 RA, palonosetron, simultaneously targets two critical antiemetic pathways, thereby offering a simple convenient antiemetic with long-lasting protection from CINV. This study is the first head-to-head NK 1 RA comparative study in patients receiving anthracycline cyclophosphamide (AC) and non-AC moderately emetogenic chemotherapy (MEC). Patients and Methods. This was a pragmatic, multicenter, randomized, single-cycle, open-label, prospective study designed to demonstrate non-inferiority of single-dose NEPA to a 3-day aprepitant regimen in preventing CINV in chemotherapy-naïve patients receiving AC/non-AC MEC in a real-life setting. The primary efficacy endpoint was complete response (no emesis/no rescue) during the overall (0-120h) phase. Non-inferiority was achieved if the lower limit of the 95% CI of the difference between NEPA and the aprepitant group was greater than the non-inferiority margin set at -10%. Results. Non-inferiority of NEPA versus aprepitant was demonstrated (risk difference 9.2%; 95% CI -2.3%, 20.7%); the overall complete response rate was numerically higher for NEPA (64.9%) than aprepitant (54.1%). Secondary endpoints also revealed numerically higher rates for NEPA than aprepitant. Conclusion. This pragmatic study in cancer patients receiving AC and non-AC MEC revealed that a single dose of oral NEPA plus DEX was at least as effective as a 3-day aprepitant regimen, with indication of a potential efficacy benefit for NEPA. The Oncologist ;9999:• • Implications for Practice: In the absence of comparative NK 1 receptor antagonist (RA) studies, guideline committees and clinicians consider NK 1 RA agents to be interchangeable and equivalent. This is the first head-to-head study comparing one NK 1 RA (oral NEPA [netupitant/palonosetron]) versus another (aprepitant) in patients receiving anthracycline cyclophosphamide (AC) and non-AC moderately emetogenic chemotherapy. Non-inferiority of NEPA versus the aprepitant regimen was demonstrated; the overall complete response (no emesis and no rescue use) rate was numerically higher for NEPA (65%)