Experimental therapy of sickle cell disease. Use of hydroxyurea.

Purpose: Therapy of sickle cell disease with hydroxyurea is experimental.

Patients and methods: We have begun a randomized blinded clinical trial to determine its clinical utility. The efficacy of this drug is unproved and its risks, which include mutagenesis, teratogenesis and carcinogenesis, are poorly understood. These risks are explicitly stated in our consent forms. A significant number of patients who are asked to enroll refuse to enter the study. This refusal is probably because of individual variations in perception of risk and personal inconvenience, as well as differences in perception of personal benefit. We have a few hints as to which patients are more likely to produce increased amounts of fetal hemoglobin, but our findings do not indicate which patients are most likely to show a good clinical response.

Results: Our study group decided not to treat patients under 18 years of age with hydroxyurea until clinical efficacy of the drug is proved in adults. We have criteria for selecting patients for entry into our ongoing study, but the criteria are based more on study design than on an estimate of present or future severity of the manifestations of sickle cell disease.

Conclusions: Features of our previous study and results of the present trial may be helpful in defining indications for bone marrow transplantation in children with sickle cell disease.