Extended therapy with intravenous arginine butyrate in patients with βHemoglobinopathies

Enhanced production of fetal hemoglobin lessens the severity of β-thalassemia and sickle cell disease. Intravenous infusion of arginine butyrate can increase the number of reticulocytes containing fetal hemoglobin in patients with these disorders, and it has induced a substantial increase in hemoglobin in one patient with thalassemia. We therefore tested the efficacy of this agent in patients with β-hemoglobinopathies. We treated 10 patients with severe β-thalassemia or sickle cell disease with arginine butyrate at an initial dose of 500 mg per kilogram of body weight per day (final dose, 2000 mg per kilogram per day), 6 days per week, for a mean (±SD) of 10±1.2 weeks (range, 9 to 13). A hematologic response was defined as an increase in the hemoglobin concentration of at least 2 g per deciliter in patients with thalassemia and as a twofold increase in fetal hemoglobin in patients with sickle cell disease. There were increases in ²globin messenger RNA and in reticulocytes containing fetal hemoglobin, but no increases in hemoglobin, in the patients with thalassemia. A small, unsustained increase in fetal hemoglobin was observed in two patients with sickle cell disease. Drug toxicity was minimal at standard doses. One patient had a grand mal seizure after inadvertently receiving 2000 mg of arginine butyrate per kilogram over a period of six hours. Ten weeks of intravenous arginine butyrate did not produce a hematologic response in 10 patients with either severe β-thalassemia or sickle cell disease.