Can prognostic factors identify women receiving anthracycline plus cyclophosphamide-based chemotherapy (MEC) who do not require an NK1 receptor antagonist?

Abstract

e20502 Background: Age, alcohol use, and history of sickness associated with pregnancy or motion have been identified as risk factors for chemotherapy-induced emesis. This post hoc analysis addressed two questions: 1) Can prognostic factors identify a low risk group for whom ondansetron (OND) plus dexamethasone [D] alone provide a high level of protection (≥80% no emesis)? 2) Does the NK1 receptor antagonist aprepitant improve antiemetic outcome regardless of emetic risk? Methods: The analysis was based upon outcomes in patients with breast cancer enrolled in a Phase III double-blind, placebo-controlled trial randomized to Day 1 OND 8 mg and D 20 mg before chemotherapy and OND 8 hours later and OND 8 mg bid Days 2–3 vs. Day 1 aprepitant 125 mg PO, OND 8 mg, and D 12 mg before chemotherapy and OND 8 mg 8 hours later and aprepitant 80 mg PO qd Days 2–3. Multivariate logistic regression models were used to assess the impact on emesis of the regimen with aprepitant, and previously reported risk factors, including age (<55 and ≥55 years), ethanol use (0–4 or ≥5 drinks/week), history of pregnancy-related morning sickness, and history of motion sickness, using a modified intent-to-treat approach. Results: 856 patients were assessed for efficacy. Treatment with aprepitant (p<0.0001), older age (p=0.006), ethanol use (p=0.0048), and no history of morning sickness (p=0.0007) were all significantly associated with reduced likelihood of emesis; motion sickness was not a risk factor. The Table below shows the probability of no emesis associated with the presence of 0, 1, 2, or all of these factors in the aprepitant and active control arms. Conclusions: 1) The low-risk group identified by this analysis is of questionable utility because it comprised less than 3% of patients. 2) We could not confirm that motion sickness was a significant risk factor. 3) Aprepitant improved the control of emesis irrespective of the number of risk factors for emesis. [Table: see text] [Table: see text]