Olanzapine for the Prevention of Chemotherapy-Induced Nausea and Vomiting: A Comparative Study From Sudan

Chemotherapy-induced nausea and vomiting (CINV) is a distressing adverse effect. Neurokinin-1 receptor antagonist (NK1RA)-containing regimens are the standard regimens for CINV prophylaxis in patients with cancer receiving highly or moderately emetogenic chemotherapy (HEC or MEC). NK1RA agents are expensive and were not registered in Sudan. Recently, regimens containing olanzapine, the available and affordable medication in Sudan, were introduced as another option. This study aimed to compare the efficacy of an olanzapine-containing regimen with the antiemetic regimen that was currently used in our institute for CINV prophylaxis in HEC/MEC settings.

The study prospectively compared an olanzapine-containing regimen (acute phase: olanzapine, ondansetron, dexamethasone; delayed phase: olanzapine, ondansetron) with an ondansetron/dexamethasone regimen (acute phase: ondansetron, dexamethasone; delayed phase: ondansetron) in adult patients with cancer receiving HEC or MEC. The study outcomes were complete response (CR; no emesis and no rescue medications) and nausea control (no nausea), which were assessed in the acute (0 to 24 hours), delayed (24 to 120 hours), and overall (0 to 120 hours) phases.

The study included 131 patients (olanzapine-containing: 50 patients; ondansetron/dexamethasone: 81 patients). CR and nausea control were higher in the olanzapine-containing than in the ondansetron/dexamethasone regimen (CR: acute phase, 86% v 71.6%; P = .086; delayed phase, 72% v 30.9%; P < .001; overall phase, 66% v 25.9%; P < .001; nausea control: acute phase, 86% v 74.1%; P = .127; delayed phase, 76% v 34.6%; P < .001; overall phase, 72% v 29.6%; P < .001). The major toxicity of olanzapine was grade 1 and 2 sedation or drowsiness (25 patients).

An olanzapine-containing regimen has better efficacy for prevention of CINV in the HEC/MEC setting. Oncologists working in a limited-resource setting should be familiar with olanzapine-containing regimens, because NK1RA agents are not affordable and not easily available.