Background: Chemotherapy-induced nausea and vomiting (CINV), a common side effect of chemotherapy, can substantially impair a patient's quality of life, interfere with a patient's compliance with anticancer therapy, and result in the manifestation of adverse events such as electrolyte imbalance, dehydration and malnutrition. The most recent guidelines published by the Multinational Association of Supportive Care in Cancer (MASCC) and European Society of Medical Oncology (ESMO) recommend the combination of dexamethasone (DEX), a 5-hydroxytrypatmine-3 receptor antagonist (5-HT3RA), preferably palonosetron (PALO), and a neurokinin-1 receptor antagonist (NK1RA) for prophylactic treatment of CINV in patients receiving highly emetogenic chemotherapy (HEC). The aim of this review was to examine the efficacy of triple agent, as reported in randomized controlled trials (RCTs), compared to any other prophylactic treatments.

Methods: A literature search was conducted in Ovid MEDLINE(R), Embase Classic & Embase, and the Cochrane Central Register of Controlled Trials. The primary endpoint was the proportion of patients achieving complete response (CR) in the acute, delayed and overall phase. Secondary endpoints included the percentage of patients who achieved complete control (CC), no nausea and no vomiting in the acute, delayed and overall phases.

Results: A total of 17 RCTs were included in this review, of which 3,146 patients were randomized to receive NK1RA, PALO and DEX, and 2,987 patients to receive other antiemetic treatments. The combination was not superior to other treatments in five endpoints-CC and CR in the acute phase, nausea and emesis control in the delayed phase, and nausea in the overall phase-but was superior in the other 11 endpoints. When looking only at HEC and moderately emetogenic chemotherapy (MEC) studies, the combination was only superior to others in three endpoints (delayed and overall CC, and overall emesis control) in HEC setting, which is less than the nine identified endpoints (delayed and overall CR, delayed and overall CC, acute and overall nausea control, and acute, delayed and overall phases for emesis control) in the MEC setting.

Conclusions: The combination of NK1RA, PALO and DEX is superior in the majority of assessed endpoints of this meta-analysis. Further studies should investigate the efficacy and safety of the triple regimen compared to regimens lacking NK1RA, to add to the discussions about whether future CINV prophylaxis guidelines should include NK1RA as a first-line treatment in the MEC setting.