Efficacy of 3-day versus 5-day aprepitant regimens for long-delayed chemotherapy-induced nausea and vomiting in patients receiving cisplatin-based chemotherapy

Chemotherapy-induced nausea and vomiting (CINV) is an ongoing problem. While effectiveness of triplet antiemetic regimens in the delayed CINV phase (24–120 hours after administration of chemotherapy) has been studied, their effectiveness in the long-delayed phase (120–168 hours post-administration) is unknown. We compared the efficacy of 3- and 5-day courses of a triplet antiemetic prophylaxis containing aprepitant (APR) in controlling long-delayed CINV after cisplatin (CDDP)-based chemotherapy. We obtained patient-level data from a nationwide, multicenter, prospective observational study in Japan. The incidence and timing of CINV after 3- and 5-day APR-containing regimens were compared using inverse probability treatment weighting. The analysis included 380 patients. The incidence rates of long-delayed nausea and vomiting were significantly reduced for the 5-day compared with the 3-day regimen (29.1% vs. 22.2%, <i>p</i> = 0.0042; 6.7% vs. 0%, <i>p</i> &lt; 0.0001, respectively). Among those without CINV, vomiting was not reported after day 2 in the 5-day APR group but increased after day 4 in the 3-day APR group. A 5-day regimen triplet antiemetic prophylaxis with APR decreased long-delayed vomiting compared with a 3-day regimen in patients receiving CDDP-based chemotherapy. However, the 5-day regimen showed no advantage over the 3-day regimen against long-delayed nausea.