Haemoglobin F modulation in childhood sickle cell disease.

While supportive care remains the best option for most well children with sickle cell disease (SCD), increasing awareness of early signs of chronic organ damage in childhood has focused attention on therapy which modulates the natural history of the disease. Since cure by stem cell transplantation is only feasible for a minority and gene therapy remains developmental, pharmacological modification by Haemoglobin F (HbF)-inducers, is the most widely used approach in SCD. Currently, the only HbF modulator with a clear place in the management of childhood SCD is hydroxycarbamide for which the main indications are frequent painful crises and recurrent acute chest syndrome. In the majority of SCD children treated with hydroxycarbamide there is clear evidence of clinical benefit and the drug is well tolerated. The main disadvantages are the need for frequent monitoring and uncertainity about long-term risks of carcinogenicity and impaired fertility, although these risks appear to be very low. The role of hydroxycarbamide in sickle-associated central nervous system disease remains to be established. Decitabine and butyrate derivatives show some promise although robust data in children with SCD are lacking. A number of other drugs are currently under investigation for their effects on HbF production including thalidomide and lenolidamide.