After signing informed consent, eligible patients are randomized with stratification (previously received or not received high emetogenic therapy; regimens with and without cisplatin) to receive the first cycle of highly emetogenic chemotherapy with standard prophylaxis (5-HT3 receptor antagonist, dexamethasone, aprepitant) with or without addition of 0.07 mg/kg olanzapine (rounded to multiples of 2.5 mg, maximum 5 mg). During chemotherapy and 120 hours after its completion, patients are assessed for the presence and absence, as well as the severity of CINV, the need for rescue therapy, and the development of adverse events. In the future, patients undergo a similar course of highly emetogenic chemotherapy with a change in the antiemetic prophylaxis option - crossover (patients who received an olanzapine regimen as antiemetic prophylaxis after the first cycle of chemotherapy receive treatment without it, patients who received prophylaxis without olanzapine receive a second cycle of therapy with olanzapine). After this cycle, the presence and absence, as well as the severity of CINV, the need for salvage therapy, the development of adverse events are assessed and, additionally, at the end of the cycle, patients are asked about the preferred option for further antiemetic prophylaxis (the regimen with olanzapine, no olanzapine, or no preferences).
Chemotherapy-induced nausea and vomiting continues to be a significant problem in children and adolescents. Standard antiemetic therapy, including a 5-HT3 antagonist, aprepitant, and a corticosteroid, achieves complete control in less than 50% of patients. Studies have shown that the addition of large doses of olanzapine improves control, including in children and adolescents. However, olanzapine has not yet been included in standard recommendations in the pediatric population. Studies in adults indicate that the dose of the drug can be halved without loss of effectiveness and with a decrease in toxicity. This open-label, randomized, phase III trial evaluates the efficacy and safety of adding low-dose olanzapine to standard prevention of nausea and vomiting induced by highly emetogenic chemotherapy in children and adolescents.