Should clinicians always administer dexamethasone beyond 24 h after chemotherapy to control delayed nausea and vomiting caused by moderately emetogenic regimens? Insight from the re-evaluation of two randomized studies

PURPOSE: Data from two noninferiority trials of a dexamethasone-sparing regimen were assessed for the impact of acute nausea and vomiting on delayed outcome in patients undergoing moderately emetogenic chemotherapy (MEC) or anthracycline plus cyclophosphamide (AC). METHODS: Chemo-naive patients were randomized to receive palonosetron (0.25 mg IV) plus dexamethasone (8 mg IV) on day 1 of chemotherapy, or the same regimen followed by oral dexamethasone on days 2 and 3 in the MEC (n = 237) and AC (n = 380) cohorts. Patients were divided into two groups according to whether or not they experienced vomiting and/or moderate-to-severe nausea during the acute phase (high- and low-risk groups, respectively). Primary efficacy endpoint was the complete protection (CP) against delayed vomiting and moderate-to-severe nausea. Patient’s satisfaction (0–100 mm visual analog scale) was also analyzed. RESULTS: Among the 209 low-risk patients undergoing MEC, delayed CP occurred in 82.9 % of those who received single-dose dexamethasone and 89.8 % of those who received 3-day dexamethasone (P = 0.165). Of the 271 low-risk patients undergoing AC, CP was achieved in 71.7 % of those treated with single-dose dexamethasone and 84.2 % treated with 3-day dexamethasone (P = 0.019). In spite of these observations, the patient satisfaction data was not influenced by dexamethasone regimen. In both cohorts, occurrence of acute vomiting or moderate-to-severe nausea was the key independent-predictor for delayed vomiting or nausea, respectively. CONCLUSIONS: The dexamethasone-sparing regimen provides adequate delayed protection in patients undergoing MEC who are at low risk for delayed symptoms, and can still be discussed for low-risk AC patients as the daily difference in control is modest. Additional dexamethasone doses can be customized on the basis of occurrence or absence of acute symptoms in the first cycle of MEC and even AC.