RCT: Olanzapine Improves Nausea and Vomiting Control in Moderately Emetogenic Chemotherapy but Increases Somnolence

Study Design and Population: This phase 3, multicenter, open-label randomized clinical trial involved 560 chemotherapy-naive patients aged 18 years or older with solid malignant tumors. The trial, conducted at three institutes in India, compared the efficacy of adding olanzapine to standard antiemetic therapy in patients receiving moderately emetogenic chemotherapy (MEC) based on oxaliplatin, carboplatin, or irinotecan.

Main Findings: The group receiving olanzapine in addition to standard antiemetic therapy showed significantly higher complete response (CR) rates (91% vs 82%, P = .005) compared to the observation group. The olanzapine group also demonstrated superior control of nausea (96% vs 87%, P < .001) and chemotherapy-induced nausea and vomiting (CINV) (96% vs 91%, P = .02). The use of rescue medications was significantly lower in the olanzapine group. Grade 1 somnolence occurred in 10% of patients receiving olanzapine but was absent in the observation group.

Implications for Practice: The results support the inclusion of olanzapine in antiemetic regimens for MEC to improve CINV outcomes. However, mild somnolence should be considered when prescribing olanzapine as part of antiemetic prophylaxis. Further research could explore dose optimization to minimize adverse effects.

Reference: Ostwal, V. et al. (2024). Olanzapine as antiemetic prophylaxis in moderately emetogenic chemotherapy: a phase 3 randomized clinical trial. JAMA Network Open. DOI: http://doi.org/10.1001/jamanetworkopen.2024.26076

Link: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2822027