A PHASE-II STUDY OF ONDANSETRON AS ANTIEMETIC PROPHYLAXIS IN PATIENTS RECEIVING 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 hematological 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 phenothiazines are extensively used but are unable to control emesis. The new antiemetic ondansetron, a serotonin receptor (5HT(3)) antagonist appears to be superior to these drugs for cisplatin-induced emesis. The study we present here is an attempt to control emesis following high-dose regimens, during bone marrow or peripheral stem cell transplantation, with ondansetron. To our knowledge no other paper has reported the efficacy of this antiemetic in such group of patients. A total of 29 patients who received highly emetogenic polychemotherapy as conditioning regimens for bone marrow transplantation were treated with ondansetron, which was given as an 8-mg i.v. short infusion prior the initiation of treatment and every 6h thereafter for 3 days, and an 8-mg dose every 8 h for 5 additional days. All the patients had previously been treated 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 the 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 had no or mild nausea. The most frequent side-effects were headache (24%) and constipation (17%). On the basis of these results we conclude that ondasetron can be succesfully used as an effective antiemetic prophylaxis for patients who receive megatherapy and bone marrow rescue, and should allow the majority of these patients to receive their treatment without serious side-effects and discomfort.