In the study, the primary endpoint was the proportion of patients who achieved a complete response, defined as absence of vomiting and no use of rescue medications in the delayed phase (24–120 hours). The researchers note their finding regarding the difference in complete response is clinically relevant as it exceeded the minimum difference of 10% for most efficacy assessments, which is the threshold recommended by the Multinational Association of Supportive Care in Cancer/European Society for Medical Oncology (MASCC/ESMO) guideline. They suggest that olanzapine 5 mg combined with aprepitant, palonosetron, and dexamethasone could be a new standard antiemetic therapy in patients undergoing cisplatin-based chemotherapy.
According to a commentary, there is mounting evidence that olanzapine is a useful addition to antiemetic regimen and the question of dose is sufficiently answered by this trial, alongside other smaller studies and phase 2 trials. It notes that a meta-analysis of ten olanzapine trials has emphasised that the 5 mg dose exhibits similar efficacy (if not better) to the 10 mg dose when compared with placebo for the delayed (24–120 h) and overall (0–120 h) phase, with fewer side-effects. It suggests that perhaps a 10 mg dose can be reserved for patients who continue to experience chemotherapy-induced nausea and vomiting despite the use of 5 mg olanzapine. It adds that future research questions include whether olanzapine can replace some antiemetics from the three-drug combination of aprepritant, dexamethasone, or palonosetron; whether adding the drug to antiemetic therapy regimens is cost-effective; whether olanzapine use is associated with decreases in the dose of dexamethasone; whether the drug plays a role as a breakthrough or rescue antiemetic; and whether it can be used to treat other areas of nausea and vomiting in patients with cancer, such as during radiotherapy or in advanced cancer.