Purpose <p>Our previous study showed that the preventive effects of fosnetupitant (F-NTP) against chemotherapy-induced nausea and vomiting (CINV) were superior to those of fosaprepitant (F-APR) or aprepitant (APR). To evaluate the cost-effectiveness of F-NTP compared with F-APR or APR in Japan, a cost-utility analysis was performed.</p> Methods <p>A decision tree model was developed based on real-world data to compare the CINV prevention ability of each neurokinin-1 receptor antagonist (NK₁ RA) in Japanese patients receiving cisplatin-based regimens. We evaluated the patients 7&#xa0;days after the first course of treatment. Quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs) were calculated to examine the cost-effectiveness of the antiemetic therapy. The probabilities of health states and medical costs were derived from the results of our previous study. These cost-utility analyses were performed from the perspective of the payers.</p> Results <p>The incremental QALYs of F-NTP relative to F-APR and APR were 0.00180 and 0.00153, respectively. The ICER of F-NTP relative to F-APR was 22,802.21 US dollars (USD) per QALY gained, which was lower than the willingness-to-pay (WTP) threshold (38,043.06 USD: 5 million Japanese Yen/QALY). Contrastingly, the ICER of F-NTP relative to APR was 40,119.64 USD/QALY, which was slightly above the WTP threshold, indicating that F-NTP may be slightly less cost-effective.</p> Conclusion <p>F-NTP is more cost-effective than F-APR, but slightly less cost-effective than APR.</p>