Feasibility of Olanzapine at REduced doSe in hIGHly Emetogenic chemoTherapy

Olanzapine is frequently used off-label as an adjunct antiemetic in clinical oncology settings. North American oncology guidelines recommend it as salvage therapy and as add-on to the standard triple regimen; some suggest it may also be effective as an initial triple therapy (olanzapine replacing the NK-1 antagonist) based on phase II and III trials. This prospective, multi-center, open-label study aims to evaluate the feasibility of a large scale randomised controlled trial to compare the effectiveness and tolerability of 5mg orally once daily olanzapine in triple antiemetic therapy versus the standard treatment of aprepitant + ondansetron + dexamethasone in treatment-naive patients receiving the first cycle of a highly emetogenic chemotherapy. Secondary outcomes include effectiveness, tolerability and quality of life assessments. Effectiveness will be measured with complete response and complete remission rates in each treatment arms. Tolerability and patient quality of life will be evaluated with a standardised side effect form and validated questionnaires; ESAS-R and FLIE. The role of olanzapine-based triple therapy in prevention of chemotherapy-induced nausea and vomiting remains founded on low-quality evidence. To the investigator's knowledge, this study will be the first large scale direct comparison of 5mg olanzapine versus aprepitant in triple therapy.