CHICAGO—Among patients with lung cancer on highly emetogenic chemotherapy, those receiving palonosetron throughout all cycles of chemotherapy had a 31% lower risk of chemotherapy-induced nausea and vomiting (CINV) associated with an emergency department or hospital visit, than patients receiving other 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists (RAs).
The study was presented by Hind T. Hatoum, PhD, of the Center of Pharmacoeconomic Research at the University of Illinois at Chicago during the 46th annual meeting of the American Society of Clinical Oncology.
The study compared the risk of serious CINV among 1692 lung cancer patients initiated on cisplatin-based chemotherapy who were started and maintained on a 5-HT3–based prophylactic strategy, including palo nosetron, dolasetron, granisetron, or ondansetron. Patients were identified from claims data (Phar-Metrics) between 2005 and 2008 and stratified into one of two groups: palonosetron throughout all cycles of chemotherapy (n = 390) and any other 5-HT3–based regimen (n = 1302).
CINV events were identified from emergency department and hospital claims with codes of nausea, vomiting, and/or dehydration. The two groups were compared for the risk of CINV, controlling for age, sex, comorbidity, and chemotherapy treatment days.
The two treatment groups had comparable comorbidities, with no significant differences in the Charlson Comorbidity Index.
The most widely represented chemotherapy regimens were cisplatin/etoposide (25%), cisplatin alone (7%) and cisplatin/docetaxel/etoposide (6%).
In what Hatoum called a “realworld practice,” the average patient receiving palonosetron had significantly fewer claims of both 5-HT3 RAs and all antiemetics, as compared with patients receiving all other 5-HT3 RAs: 6.4 versus 12.4 for other 5-HT3 RA claims (P <.0001), and 8.5 versus 14.7 in all antiemetic claims (P <.0001).
This represents 42% fewer antiemetic claims and 58% fewer 5-HT3 RA claims for palonosetron compared with patients who received other agents, Hatoum noted.
With palonosetron, fewer patients experienced CINV events leading to emergency department or hospital visits: 16.4% versus 22.6% (P <.01) in the unadjusted analysis, which remained a significant 31% reduction (P <.05) in the adjusted analysis.
Palonosetron-treated patients also had, on average, significantly fewer cisplatin treatment days: 4.9 versus 5.7 days (P <.0001). “We cannot ascertain with 100% certainty what this means, but we suspect these patients were able to have the dose pushed higher because they had less nausea and vomiting. They did not have to delay treatment; and therefore, there were fewer treatment days,” Hatoum suggested.
In addition, 51.0% of patients used palonosetron without combining it with the neurokinin-1 (NK1) antagonist aprepitant and/or dexamethasone, compared with 45.6% of the alternate group. Palonosetron, in contrast to other 5-HT3 RAs, differentially in hibits “crosstalk” between NK1 re ceptors and 5-HT3 signaling pathways, and exhibits prolonged inhibition of receptor function, Hatoum explained, suggesting that “it may have properties such that you don’t need the NK1 antagonist.”.