Optimizing Antiemetic Strategies Across Phases of Chemotherapy-Induced Nausea and Vomiting: Real-World Evidence in Breast Cancer

BACKGROUND: Chemotherapy-induced nausea and vomiting (CINV) remains one of the significant challenges in oncology despite guideline-based prophylaxis, particularly in patients receiving highly emetogenic chemotherapy (HEC). While neurokinin-1 (NK-1) receptor antagonists are established as a key component of standard antiemetic regimens, evidence of their phase-specific effectiveness in real-world, homogeneous patient populations remains limited. This study aimed to determine which antiemetic regimen provides optimal control in each CINV phase to support a tailored prophylactic approach. METHODS: receptor antagonist, dexamethasone, and an NK-1 receptor antagonist (either a single-dose intravenous fosaprepitant or a 3-day oral aprepitant). Complete response (no vomiting and no rescue therapy) and no-vomiting rates were assessed in the acute (0-24 h), delayed (24-120 h), and overall (0-120 h) phases. RESULTS: In this relatively homogeneous cohort of high-risk patients, fosaprepitant-based prophylaxis achieved better symptom control during the acute phase, whereas aprepitant-based regimens were more effective in the delayed and overall phases. These findings suggest phase-specific variations in antiemetic effectiveness that reflect pharmacokinetic and administration-route differences rather than population heterogeneity. CONCLUSIONS: This real-world analysis demonstrates that antiemetic effectiveness varies by CINV phase, even within a relatively homogeneous, high-risk patient cohort. The results highlight the importance of phase-tailored prophylactic strategies to optimize symptom control and improve patient quality of life in highly emetogenic chemotherapy settings.