Objective: Current guidelines support the use of 5-HT3-RAs for chemotherapy-induced nausea and vomiting (CINV). Controlling CINV upon chemotherapy initiation is important as the likelihood of CINV in future chemotherapy cycles increases if a patient experiences CINV in the first/previous chemotherapy cycle. The purpose of this study was to evaluate the overall rate of CINV, and compare the odds of CINV per chemotherapy cycle in patients with lung cancer receiving the same 5-HT3-RA throughout chemotherapy cycles.
Methods: A retrospective database analysis was conducted utilizing medical and pharmacy claims from 2005-2011 in a commercial (96%) and Medicaid (4%) population. Continuously enrolled patients (6 month pre-period, 6 month post-period) with a diagnosis of lung cancer receiving single-day chemotherapy regimens were eligible. Patients were required to remain on the initial 5-HT3-RA therapy and same level of emetic potential of chemotherapy throughout. CINV was defined as a primary or secondary diagnosis of nausea, vomiting, or dehydration or use of rescue antiemetic medication. Overall rates of CINV were calculated, and odds for CINV for each chemotherapy cycle were calculated by 5-HT3-RA agent. Patients without CINV in the previous cycle or who switched 5-HT3-RA therapy were excluded from subsequent calculations.
Results: A total of 3,863 patients were included in the analysis. Average age was 61 years, and mean Charlson Comorbidity score was 5.3. The overall CINV rate regardless of 5-HT3-RA was 17% at Cycle 1, and more than doubled for Cycle 2 and Cycle 3 (39.0% and 71.8%, respectively). Multivariate analysis showed patients receiving ondansetron, granisetron, or dolasetron had significantly higher odds of developing CINV at Cycle 2 vs palonosetron (Cycle 2 OR: 2.02; 95% CI: 1.23, 3.32 for ondansetron, OR: 2.79; 95% CI: 1.73, 4.49 for granisetron, OR: 1.85; 95% CI: 1.03, 3.32 for dolasetron; p<0.05 for all comparisons) and significantly higher odds for ondansetron and granisetron vs palonosetron at Cycle 3 (Cycle 3 OR: 3.36; 95% CI: 1.22, 9.24 for ondansetron, OR: 2.65; 95% CI: 1.07, 6.57 for granisetron; p<0.05 for each).
Conclusions: CINV rates increased in subsequent chemotherapy cycles for patients who experienced CINV and maintained therapy with the same 5-HT3-RA. For patients receiving palonosetron, the odds of experiencing CINV in subsequent cycles was lower than patients receiving one of the other 5-HT3-RAs.