5-HT3 Receptor Antagonist Effects in Cancer Patients With Multiple Risk Factors

Objectives: To examine the impact of palonosetron versus other 5-HT3 receptor antagonists (RAs) on the incidence of delayed chemotherapy-induced nausea and vomiting (CINV) in cycle 1 of chemotherapy based on the presence of the following risk factors: age < 50 years, female sex, prior CINV, anxiety, no or minimal alcohol use, history of motion sickness, and emetogenicity of chemotherapy. Study Design: Retrospective claims analysis. Methods: A retrospective claims analysis was conducted using the OptumInsight database from December 1, 2005, to June 30, 2011. Continuously enrolled cancer patients aged >= 18 years initiated on their first chemotherapy were included. Patients with a previous cancer diagnosis in the pre-index period or receiving multi-day chemotherapy were excluded. The study population was examined for differences in CINV rates by each 5-HT3 RA, stratified by number of risk factors. CINV was identified using International Classification of Diseases, Ninth Revision, Clinical Modification, codes for nausea, vomiting, or related events, and rescue medication use within 5 days. Results: Final analysis included 26,974 patients. Overall, the percentage of patients experiencing CINV increased as the number of risk factors increased: 13.5%, 14.9%, 15.6%, and 18.4% for 0, 1, 2, and 3 or more risk factors, respectively. High-risk patients (>= 3 risk factors) receiving palonosetron had fewer CINV events compared with those receiving ondansetron, granisetron, and dolasetron. Odds ratios versus palonosetron were: 1.523 (95% CI, 1.231-1.883), 1.426 (95% CI, 1.146-1.773), and 1.683 (95% CI, 1.271-2.229), respectively. Conclusions: Palonosetron was significantly more effective than all other 5-HT3 RAs in patients at the highest risk of developing CINV.