Efficacy of Olanzapine, Netupitant, and Palonosetron in Controlling Nausea and Vomiting Associated with Highly Emetogenic Chemotherapy in Patients with Breast Cancer (OLNEPA)

Purpose: Chemotherapy-induced nausea and vomiting is a highly prevalent adverse event that could lead to worse treatment adherence and decreased quality of life 1,2 . To our knowledge, total dexamethasone omission from any regimen to prevent nausea and vomiting has not been evaluated 2-4 . This study aimed to address the efficacy of a three-drug protocol in preventing nausea and vomiting, with no corticosteroids included. Methods: This was a prospective single-arm phase II study designed to evaluate the efficacy of olanzapine, netupitant, and palonosetron in controlling nausea and vomiting induced by highly emetogenic chemotherapy. Patients were assigned to take olanzapine on Days 1–5 and netupitant and palonosetron on Day 1. No corticosteroid use was allowed. The primary endpoint was complete control of nausea in the first 5 days after chemotherapy administration. Secondary endpoints were complete emesis control (no emesis and no use of rescue medication) and complete control (no emesis, no rescue, and no nausea). Results: For the primary endpoint, the complete nausea control rate was 46% (CI 32–59%), with p < 0.0001. The emesis control rate was 68% (IC 55–80%), and the overall control rate was 46% (IC 32–59%). Conclusion: Omitting dexamethasone for highly emetogenic chemotherapy is feasible and showed a nausea and vomiting control rate that was similar to that of the standard four-drug protocol. Trial registered by the number NCT04669132, on December 16, 2020, on clinicaltrials.gov platform.