Palonosetron Versus Other 5-HT₃-Receptor Antagonists for the Prevention of Chemotherapy Induced Nausea and Vomiting In Patients with Hematologic Malignancies Treated In A Hospital Outpatient Setting

This analysis explored the risk of uncontrolled chemotherapy induced nausea and vomiting (CINV) associated with initiation of palonosetron versus other 5-hydroxy tryptamine₃-receptor antagonists (5-HT₃-RAs) among patients with leukemia and/or lymphoma receiving chemotherapy (CT) [highly emetogenic chemotherapy, moderately emetogenic chemotherapy, low emetogenic chemotherapy, or minimal emetogenic chemotherapy] treatment in a hospital outpatient setting.

Patients diagnosed with any leukemia and/or lymphoma [identified through appropriate International Classification of Diseases, Clinical Modification, 9^th Revision codes (ICD-9-CM)] initiating any CT and anti-emetic prophylaxis with palonosetron (Group 1) or other 5-HT₃-RAs (Group 2) for the first time (index date) between April 1, 2007 and March 31, 2009 were identified from the Premier Perspective comparative research database. Other inclusion criteria were patients aged ≥ 18 years, no prior evidence of nausea and vomiting or a hospital charge for a CT or anti-emetic medication in the 6-month pre-index date period, and at least one CINV event in the post-index date follow-up study period. Patients also needed to have at least 36 consecutive months of hospital data submissions. Patients were followed through eight CT cycles or six months post index date, whichever occurred first. The unit of analysis was a CT cycle. Group 1 and Group 2 patients were matched on type of CT, specific CT cycle, and leukemia/lymphoma diagnosis using propensity scoring. A negative binomial distribution generalized linear multivariate regression model estimating the number of CINV events (identified through either ICD-9-CM codes for nausea and/or vomiting and volume depletion or CINV-related rescue medications one day after CT administration) in the follow-up period between the matched groups was developed after adjusting for other significant differences in demographic and clinical variables at index date (baseline) including age, gender, patient weight, payor type, patient race, CT cycle duration, and CT duration in days.

Of 1,256 identified patients, 234 initiated with palonosetron (Group 1; 18.6%). Group 1 patients were significantly younger [60.8 (SD: 17.9) vs. 64.4 (14.8) years; p=0.0045], comprised more females [49.6% vs. 43.2%; p<0.0001], received more emetogenic CT (high and moderate) [88.5% vs. 77.1%; p<0.0001], and less African Americans [9.4% vs. 12.7%]. Group 1 also had a lower percentage of patients with leukemia [9.0% vs. 17.6%; p<0.0001], and more patients with lymphoma [82.5% vs. 63.1%; p<0.0001]. In the follow-up period, the unadjusted number of CINV events per patient per CT cycle for Group1 patients was significantly lower versus Group 2 patients (3.4 vs. 4.3 CINV events per patient per CT cycle; p<0.0001). The regression model predicted a 32% reduction in the total CINV events per patient per CT cycle for Group 1 patients versus Group 2 patients; p=0.0003. Other significant variable results from the model included patients aged < 65 years had a 39.9% lower risk of total CINV events per patient per CT cycle versus patients aged ≥ 65 years; p=0.0009 and commercially insured patients had a 44.2% lower risk of total CINV events per patient per CT cycle versus traditional Medicare patients; p=0.0003.

In this hospital outpatient retrospective database analysis, patients with hematologic malignancies initiated and maintained on palonosetron were more likely to experience a significantly lower rate of CINV events per patient per CT cycle versus those initiated on other 5-HT3-RAs.

Craver:Eisai, Inc.: Research Funding. Gayle:Eisai, Inc.: Research Funding. Balu:Eisai, Inc.: Employment. Buchner:Eisai, Inc.: Employment. Off Label Use: The study was on hematology patients on all chemotherapy types (high, moderate, low, and minimal) even though the drug (palonosetron) is approved for highly emetogenic chemotherapy and moderately emetogenic chemotherapy in the United States.