To update the guideline to include new anticancer agents, antiemetics, and antiemetic regimens and to provide recommendations on the use of dexamethasone as a prophylactic antiemetic in patients receiving checkpoint inhibitors (CPIs).

ASCO convened an Expert Panel and updated the systematic review to include randomized controlled trials (RCTs) and meta-analyses of RCTs published between June 1, 2016, and January 24, 2020. To address the dexamethasone and CPI question, we conducted a systematic review of RCTs that evaluated the addition of a CPI to chemotherapy.

The systematic reviews included 3 publications from the updated search and 10 publications on CPIs. Two phase III trials in adult patients with non-small-cell lung cancers evaluating a platinum-based doublet with or without the programmed death 1 (PD-1) inhibitor pembrolizumab recommended that all patients receive dexamethasone as a component of the prophylactic antiemetic regimen. In both studies, superior outcomes were noted in the PD-1 inhibitor-containing arms. Other important findings address olanzapine in adults and fosaprepitant in pediatric patients.

Recommendations for adults are unchanged with the exception of the option of adding olanzapine in the setting of hematopoietic stem cell transplantation. Dosing information now includes the option of a 5-mg dose of olanzapine in adults and intravenous formulations of aprepitant and netupitant-palonosetron. The option of fosaprepitant is added to pediatric recommendations. There is no clinical evidence to warrant omission of dexamethasone from guideline-compliant prophylactic antiemetic regimens when CPIs are administered to adults in combination with chemotherapy. CPIs administered alone or in combination with another CPI do not require the routine use of a prophylactic antiemetic.Additional information is available at www.asco.org/supportive-care-guidelines.