Oral isobutyramide therapy in patients with thalassemia intermedia: results of a phase II open study.

A pilot phase II open study on 12 patients with thalassemia intermedia (7 men, 5 women; age 31 +/- 2.0 years SE) treated with oral isobutyramide, a derivative of butyric acid (150 mg/kg body wt/day), was performed in order to evaluate the effect of this compound in stimulating hemoglobin F (HbF) production. No patient underwent blood transfusion in the 1-year time frame prior to the study. Nine patients were splenectomized. Safety was monitored by clinical and laboratory tests. Efficacy was assessed in terms of the non-alpha/alpha globin chain biosynthetic ratio and the percentage increase of HbF. The study design consisted of a screening phase, a treatment phase of 28 days, and a posttreatment follow-up of 28 days. All patients completed the study. Compliance to treatment was 100%. No drug-related adverse event was recorded. We observed little or no increase in the non-alpha/alpha ratio in the majority of patients. Six patients showed a percentage increase of HbF at the end of treatment and in 5 of those 6 further increases at the end of the follow-up period were observed. The change in percentage of HbF over time was close to significance both in the treatment period (P = 0. 06) and in the follow-up period (P = 0.08). These results indicate that butyrate derivatives can stimulate fetal hemoglobin in patients with intermediate thalassemia. Testing of the effects of different schedules of administration of isobutyramide will be required in order to determine the optimal use of this compound in the treatment of the beta-thalassemia syndromes. Copyright 2000 Academic Press.