A PHASE-II STUDY OF ONDANSETRON AS ANTIEMETIC PROPHYLAXIS IN PATIENTSRECEIVING HIGH-DOSE POLYCHEMOTHERAPY AND STEM-CELL TRANSPLANTATION

The field of high-dose chemotherapy with stem cell transplantation has been expanded recently as a treatment for solid tumors and hematologi cal malignancies. Severe emesis remains one of the main extramedullary side-effects of high-dose regimens during the first week of treatment , Traditional antiemetics such as chlorpromazine, diazepam, and phenot hiazines are extensively used but are unable to control emesis. The ne w antiemetic ondansetron, a serotonin receptor (5HT(3)) antagonist app ears to be superior to these drugs for cisplatin-induced emesis. The s tudy we present here is an attempt to control emesis following high-do se regimens, during bone marrow or peripheral stem cell transplantatio n, with ondansetron. To our knowledge no other paper has reported the efficacy of this antiemetic in such group of patients. A total of 29 p atients who received highly emetogenic polychemotherapy as conditionin g regimens for bone marrow transplantation were treated with ondansetr on, which was given as an 8-mg i.v. short infusion prior the initiatio n of treatment and every 6h thereafter for 3 days, and an 8-mg dose ev ery 8 h for 5 additional days. All the patients had previously been tr eated with chemotherapy and were evaluable for response and toxicity. Complete and major protection of vomiting on day 1 was achieved by 76% of the patients, 58% on day 2 and 52% on day 3. Nausea was absent or mild in 79% of patients on day 1, 45% on day 2 and 41% on day 3. For t he days 4-8 as a whole, complete and major protection against vomiting was achieved by 59%-86% of the patients, while 51%-90% of patients ha d no or mild nausea. The most frequent side-effects were headache (24% ) and constipation (17%). On the basis of these results we conclude th at ondasetron can be succesfully used as an effective antiemetic proph ylaxis for patients who receive megatherapy and bone marrow rescue, an d should allow the majority of these patients to receive their treatme nt without serious side-effects and discomfort.