Palonosetron, a second-generation 5-HT3-receptor antagonist, is at least as effective as Kytril (granisetron), a first-generation 5-HT3-receptor antagonist, in preventing nausea and vomiting due to chemotherapy up to one day after treatment.  One to five days after treatment, palonosetron remains effective in a significantly larger percentage of patients than does Kytril.

Many chemotherapy patients are subject to vomit-inducing anticancer treatment, which typically contains the drugs cisplatin or anthracycline/cyclophosphamide.  The standard preventative treatment, Kytril, works in just over 50% of patients when administered with dexamethasone prior to chemotherapy.  However, the effect wears off after a day or so, and the symptoms of nausea and vomiting return.

Mitsue Saito, M.D., of Juntendo University Hospital in Tokyo, and colleagues previously found palonosetron with dexamethasone to be an effective preventative treatment in a clinical study.  Their recent Phase 3 comparative trial, published online this month, tested palonosetron directly against Kytril in 1143 patients receiving chemotherapy from 75 institutions in Japan.  Patients were randomly assigned to receive palonosetron or Kytril 30 minutes before receiving chemotherapy and dexamethasone injections on days 1, 2, and 3 of chemotherapy.

Their results show that palenosetron performs similarly to Kytril within 24 hours of chemotherapy.  Of the patients receiving palonosetron, 75.3 percent had a complete response of no vomiting, compared with 73.3 percent in the Kytril group.  Palenosetron performs notably better than Kytril in preventing nausea and vomiting one to five days after chemotherapy.  Several days after treatment, 56.8 percent of patients who had received palonosetron had a complete response, compared with 44.5 percent in the Kytril group.  The two drugs display comparable mild-to-medium side effects, none of which surpassed grade 3.  The main side effect was constipation, which occurred in 17.4 percent of the palonosetron group and 15.7 percent of the Kytril group.

"On the basis of the results of this trial, palonosetron seems to be a safe and effective drug for the prevention of CINV," concluded Dr. Saito and colleagues.

For more information, refer to Medical News Today.  The online version of the scientific paper can be accessed at The Lancet Oncology.