Does gabapentin prevent delayed chemotherapy-induced nausea and vomiting (N/V)? Results of a randomized placebo controlled trial, NCCTG N08C3 (Alliance).

Abstract

9513 Background: The need for more research in N/V control is exemplified by agents that are costly, interfere with cytochrome P450 metabolism, and inadequately address delayed N/V. Based on pilot data, there was justification for evaluating whether gabapentin could improve the prevention of delayed N/V from highly emetogenic chemotherapy (HEC). Methods: Patients (pts) about to receive HEC were randomized to prophylactic treatment with 20 mg of dexamethasone (dex) and a 5HT3 receptor antagonist (RA) on the day of chemotherapy, followed by either gabapentin (gaba) 300 mg BID and dex or placebo (plac) and dex. Gaba/plac was started the evening of the day of chemotherapy and continued through day 5 of the first chemotherapy cycle. Dex was given at 8 mg BID days 2-3, then 4 mg BID for day 4, in both arms. The primary endpoint was complete response (CR), defined as no emesis and no rescue medications day 2-6, using a nausea and vomiting diary. The percent of CR were compared in each group by Fisher’s exact test. Secondary outcomes included the Functional Living Index-Emesis (FLIE), satisfaction, and a side effect questionnaire. Results: 430 pts were enrolled in this study between 5/2009 and 2/2011. 47% of pts in the gaba arm and 41% in the plac arm had a CR (p=.23). At some time during days 2-6, 30% in the gaba and plac arms experienced emesis, and 45% and 53% in the gaba and plac arms, respectively, took rescue medication. Mean diary nausea scores over days 2-6 ranged from 0.9 – 1.2 (gaba arm) and 1.0-1.3 (plac arm)(7 = the worst); mean number of diary emetic episodes ranged from 0.1 -0.3 (gaba arm) and 0.1-0.2 (plac arm). The FLIE was not significantly different between arms. Mean vomiting satisfaction was 9.1 in both arms and for nausea was 8.3 for gaba, 8.1 for plac (10= totally satisfied). There were no significant differences in toxicities by CTCAE provider grading or by self-report. Conclusions: In this study, gaba did not improve delayed N/V. Overall, there was little emesis and nausea severity was low. Patients were satisfied with the control of their N/V, irrespective of arm. The use of standard prophylactic guidelines that include a 5HT3RA and dex provided good control of N/V for most patients. Clinical trial information: NCT00880191.