Olanzapine for the prophylaxis and rescue of chemotherapy-induced nausea and vomiting: a systematic review, meta-analysis, cumulative meta-analysis and fragility assessment of the literature.

INTRODUCTION The aim of this study is to rigorously review the efficacy and safety of olanzapine in defined hematology oncology settings including (1) the setting of highly emetogenic chemotherapy (HEC) and moderately emetogenic chemotherapy (MEC) settings (2) at 5 mg and 10 mg doses, and (3) for response rates for use in the acute, delayed, and overall settings post-MEC and HEC. METHODS Ovid MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched through April 23, 2020. The primary efficacy endpoints were the rate of complete response, in the acute (0-24 h post-chemotherapy), delayed (24-120 h post-chemotherapy), and overall (0-120 h post-chemotherapy) phases. The secondary efficacy endpoints were the rates of no nausea and no emesis, for each phase. Safety endpoints were the rate of no serious adverse events (i.e., no grade 3 or 4 toxicities), as assessed by Common Terminology Criteria for Adverse Events (CTCAE) criteria. The Mantel-Haenszel, random-effects analysis model was used to compute risk ratios and accompanying 95% confidence intervals for each endpoint. For endpoints that statistically favored one arm, absolute risk differences were computed to assess whether there is a 10% or greater difference, used as the threshold for clinical significance by MASCC/ESMO. Fragility indices were also calculated for each statistically significant endpoint, to quantitatively assess the robustness of the summary estimate. A cumulative meta-analysis was conducted for each efficacy meta-analysis with more than 5 studies, also using the Mantel-Haenszel random-effects analysis model. RESULTS Three studies reported on olanzapine for the rescue of breakthrough chemotherapy-induced nausea and vomiting (CINV); 22 studies reported on olanzapine in the prophylactic setting. For studies reporting on HEC patients, olanzapine-containing regimens were statistically and clinically superior in seven of nine efficacy endpoints in the prophylaxis setting. When olanzapine is administered at a 10-mg dose, it is statistically and clinically superior to control patients in eight of nine endpoints among adults. Olanzapine may be effective in the MEC setting and when administered at 5-mg doses, but the paucity of data leads to notable uncertainty. CONCLUSION Further RCTs are needed in the setting of MEC patients and administration of olanzapine at a lower 5-mg dose, which may be given to reduce the sedative effect of olanzapine at 10 mg.