Palonosetron versus other 5-HT₃ receptor antagonists for prevention of chemotherapy-induced nausea and vomiting in patients with hematologic malignancies treated with emetogenic chemotherapy in a hospital outpatient setting in the United States.

OBJECTIVE: This study evaluated the rate of uncontrolled chemotherapy-induced nausea and vomiting (CINV) after initiating antiemetic prophylaxis with palonosetron versus other 5-HT₃ receptor antagonists (RAs) in patients diagnosed with hematologic malignancies (lymphoma and leukemia) and receiving highly emetogenic chemotherapy (HEC) or moderately emetogenic chemotherapy (MEC) in a hospital outpatient setting.

METHODS: Patients aged ≥ 18 years and diagnosed with hematologic malignancies initiating HEC or MEC and antiemetic prophylaxis with palonosetron (Group 1) and other 5-HT₃ RAs (Group 2) for the first time in a hospital outpatient setting between 4/1/2007 and 3/31/2009 were identified from the Premier Perspective Database. Within each cycle, CINV events were identified (in the hospital outpatient, inpatient, and emergency room settings) through ICD-9 codes for nausea, vomiting, and/or volume depletion (from each CT administration day 1 until the end of the CT cycle), or use of rescue medications (day 2 until the end of the CT cycle). Negative binomial distribution generalized linear multivariate regression model estimating the CINV event rate on CT, specific CT cycles, and cancer diagnosis (leukemia/lymphoma)-matched groups in the follow-up period (first of 8 cycles or 6 months) was developed.

RESULTS: Of 971 identified patients, 211 initiated palonosetron (Group 1). Group 1 patients comprised of more females [50.2 vs. 41.4%; p = 0.0226], Whites [74.4 vs. 70.4%, and Hispanics [7.6 vs. 6.3%; all races p = 0.0105], received more HEC treatments [89.6 vs. 84.2%; all CT types p = 0.0129], and had more lymphoma diagnosed patients [89.6 vs. 76.3%; all cancer types p = 0.0033] at baseline. After controlling for differences in several demographic and clinical variables, the regression model predicted a 20.4% decrease in CINV event rate per CT cycle for Group 1 versus Group 2 patients. Study limitations include potential lack of generalizability, absence of data on certain confounders including alcohol consumption and prior history of motion sickness, potential underestimation of incidence of uncontrolled CINV, and inability to draw conclusions pertaining to cause and effect relationship.

CONCLUSION: In this retrospective hospital study, patients with hematologic malignancies treated with HEC or MEC and initiated on antiemetic prophylaxis with palonosetron in the hospital outpatient setting were more likely to experience significantly lower CINV event rates (in the hospital outpatient, inpatient, and emergency room settings) versus patients initiated on other 5-HT₃ RAs.