This is a prospective, interventional, phase II, open-label, multicentre, national, non-comparative study of a single administration of the new dispersible form of hydroxycarbamide at the usual dose in children with sickle cell disease who are already treated with the current form of hydroxycarbamide (Siklos® 100 mg and/or 1000 mg film-coated tablets).

Inclusion Criteria:

• Written informed consent, signed and dated by both parents or by the legally acceptable representative(s) of the children,
• Child with sickle cell disease, treated with 100 mg and/or 1000 mg Siklos® film-coated tablets at the same daily dose for more than 4 weeks,
• Child aged between 2 and 6 years old,
• Parents capable of communicating with the investigator and understanding the requirements and constraints of the study protocol and willing to comply with the study requirements,
• Children affiliated to a social security plan (including universal health coverage) or beneficiary of a similar insurance plan.

Exclusion Criteria:

• Participation in any other clinical study for any other pharmaceutical product within 4 weeks preceding study inclusion,
• Known hypersensitivity or allergy to the excipients,
• Any surgical or medical condition or any significant illness (of which severe hepatic impairment (Child-Pugh classification C), severe renal impairment, toxic ranges of myelosuppression) that, in the opinion of the investigator, constitutes a risk or a contraindication to the participation of the patient to the study, or that may interfere with the objectives, conduct or evaluation of the study.