Sustained Antiemetic Efficacy of Fosnetupitant versus Aprepitant in Carboplatin-based Chemotherapy: A Retrospective Observational Study

Background: Carboplatin (CBDCA) is highly emetogenic when administered at an area under the curve (AUC) ≥4, requiring triple antiemetic therapy, including an NK ₁ receptor antagonist (NK ₁ RA). Fosnetupitant (F-NTP), a long-acting NK ₁ RA, may provide sustained receptor occupancy; however, its direct comparisons with aprepitant (APR) in CBDCA-based regimens between 0-168 h remain lacking. We aimed to evaluate the antiemetic efficacy of F-NTP versus APR between 1 week following chemotherapy. Methods: This retrospective single-center observational study included patients with cancer receiving CBDCA (AUC ≥4)-based regimens. Propensity score matching was performed using clinical factors. The primary endpoint was complete response (CR; no emesis or rescue medication) rate between 0–168 h. The secondary endpoints included phase-specific CR rates, time to treatment failure (TTF), and adverse events (AEs). Results: After matching, 242 patients were included in each group. The overall CR rate at 0–168 h was significantly higher with F-NTP (83.5%) than with APR (69.4%) ( p <0.001). F-NTP significantly prolonged TTF (hazard ratio =0.48, 95% confidence interval: 0.33–0.71, p <0.001). Multivariate analysis revealed female sex, younger age, and high CBDCA dose as significant risk factors for non-CR, while F-NTP use was a protective factor. AEs did not differ significantly between the groups and were mostly Grade 1. Conclusion: F-NTP demonstrated superior antiemetic efficacy to that of APR in CBDCA-based regimens, particularly maintaining higher CR rates through the acute and delayed phases. F-NTP was also well tolerated, supporting its potential as a strong prophylactic agent for preventing chemotherapy-induced nausea and vomiting.