Safety of a short-term infusion of fosnetupitant in patients with gastrointestinal and breast cancer: a prospective study.

BACKGROUND Fosnetupitant, a neurokinin-1 receptor antagonist, is used to prevent chemotherapy-induced nausea and vomiting (CINV) in patients undergoing highly emetogenic chemotherapy (HEC) or moderately emetogenic chemotherapy (MEC). Previous phase III trials demonstrated the non-inferiority of its 30-minute infusion to fosaprepitant in efficacy and a favorable safety profile. METHODS This was a single-arm, phase II study to investigate the safety of a 15-minute infusion of fosnetupitant in patients with gastrointestinal and breast cancer. Patients who had received their dose of fosnetupitant in a 30-minute infusion without developing an allergic reaction were eligible and received their next fosnetupitant dose for 15 minutes. The primary endpoint was the incidence of an allergic reaction during the first 15-minutes infusion, and the secondary endpoints were the incidence of injection site reaction (ISR), the incidence of a grade ≥ 3 treatment-related adverse event (TRAE) with fosnetupitant, and complete response (CR) rate. RESULTS The study period was from February 17, 2023 to June 20, 2023. In an exploratory analysis, medical records from the end of the study period to December 31, 2023 were retrospectively evaluated to assess the time-saving effect and safety of the short-term infusion of fosnetupitant. Fifty-six patients with gastrointestinal and 14 patients with breast cancer were enrolled, one of whom with breast cancer did not receive study treatment at her own request. No allergic reactions occurred during the 15-minutes infusion. Furthermore, there were no allergic reactions across all 280 short-term injections (Table 1). Additionally, no ISR or grade 3 or higher TRAE were reported. The CR rate was 87.0%. CONCLUSION Short-term infusion of fosnetupitant, administered over 15 minutes, was demonstrated to be safe and effective for patients receiving HEC or MEC (Japan Registry of Clinical Trials Trial ID: jRCT1041220144).