Pooled Analysis of Studies Evaluating Fosnetupitant and Risk Factors for Cisplatin-Induced Nausea and Vomiting During the Extended Overall Phase

INTRODUCTION: Fosnetupitant is a novel neurokinin 1 receptor antagonist (NK(1)RA) with favorable antiemetic efficacy in patients receiving emetogenic chemotherapy. This study assessed the efficacy of fosnetupitant in combination with palonosetron and dexamethasone and identified risk factors for chemotherapy-induced nausea and vomiting (CINV) for up to 168 h after treatment using pooled data from Japanese studies. METHODS: A pooled analysis of randomized phase II and phase III studies was performed to compare the efficacy of fosnetupitant and fosaprepitant in patients receiving cisplatin-based chemotherapy. The complete response (CR; no vomiting and no rescue medication) rate, CINV risk factors in various phases (0–120, 0–168, and 120–168 h), and impact of the number of risk factors on the time to treatment failure (TTF) were examined in the overall and NK(1)RA evaluable populations. RESULTS: In the combined cohort of NK(1)RA evaluable patients (n = 980), the CR rate at 0–168 h was significantly better in the fosnetupitant 235 mg group than in the fosaprepitant group (rate difference = 6.8%, 95% confidence interval = 1.0–12.7, p = 0.022). In the overall (n = 1368) and NK(1)RA evaluable populations, the CINV risk factor at 120–168 h was treatment failure in the first 120 h. TTF deteriorated as the number of identified CINV risk factors increased. CONCLUSION: This analysis revealed that fosnetupitant could have long-acting antiemetic potency (> 120 h) and indicated the importance of antiemetic therapy at 0–120 h for CINV up to 168 h after chemotherapy. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12325-023-02648-1.