Effect of Hydroxyurea on the Frequency of Painful Crises in Sickle Cell Anemia

TLDR: Hydroxyurea therapy can ameliorate the clinical course of sickle cell anemia in some adults with three or more painful crises per year and Maximal tolerated doses of hydroxyurea may not be necessary to achieve a therapeutic effect.

Abstract: Background In a previous open-label study of hydroxyurea therapy, the synthesis of fetal hemoglobin increased in most patients with sickle cell anemia, with only mild myelotoxicity. By inhibiting sickling, increased levels of fetal hemoglobin might decrease the frequency of painful crises. Methods In a double-blind, randomized clinical trial, we tested the efficacy of hydroxyurea in reducing the frequency of painful crises in adults with a history of three or more such crises per year. The trial was stopped after a mean follow-up of 21 months. Results Among 148 men and 151 women studied at 21 clinics, the 152 patients assigned to hydroxyurea treatment had lower annual rates of crises than the 147 patients given placebo (median, 2.5 vs. 4.5 crises per year, P<0.001). The median times to the first crisis (3.0 vs. 1.5 months, P = 0.01) and the second crisis (8.8 vs. 4.6 months, P<0.001) were longer with hydroxyurea treatment. Fewer patients assigned to hydroxyurea had chest syndrome (25 vs. 51, P<0.001), and...