The purpose of this interventional, phase II, national, multicentric, non-randomised, open-label study is to evaluate the pharmacokinetics (PK), efficacy and safety of Hydroxycarbamide Paediatric dispersible tablets with a twice daily dosing regimen in children with Sickle Celle Disease between 9 months to 11 years of age.

Participants will:

• Take Hydroxycarbamide twice a day every day for 12 months
• Visit the clinic at screening, baseline, 1, 3, 6, 9 and 12 months

Inclusion Criteria:

• Written informed consent, signed and dated by both parents or by the legally acceptable representative(s) of the children, and, if possible, assent from the children,
• HbSS or HbSβ0 SCD,
• Aged between 9 months and 11 years old,
• Hydroxycarbamide naïve,
• Parent(s) or legally acceptable representative(s) capable of communicating with the investigator and understanding the requirements and constraints of the study protocol and willing to comply with the study requirements,
• Contraception criterion, if applicable: for patients who are sexually active
• Affiliated to a social security plan or beneficiary of a similar insurance plan,
• Patient must meet the following laboratory values : Absolute Neutrophil Count ≥ 1.0x109/L, Platelets ≥ 75x109/L and Haemoglobin (Hgb) > 5.5 g/dL,
• Transcranial Doppler (TCD) in the last 12 months indicating low risk for stroke is required for children over 18 months of age.

Exclusion Criteria:

• Participation in any other clinical study for any other pharmaceutical product within 4 weeks preceding the inclusion visit,
• Patients who have had chronic blood transfusion or transfusion in the last 3 months preceding the inclusion visit,
• Patients treated with other SCD-modifying therapies,
• Patient with a stage 3, 4 or 5 chronic kidney disease,
• Patients known to be infected with human immunodeficiency virus, hepatitis B virus, or hepatitis C virus,
• Known hypersensitivity or allergy to the excipients,
• Any surgical or medical condition or any significant illness 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,
• Female patients who are pregnant or lactating,
• Any documented history of a clinical stroke or intracranial haemorrhage, or an uninvestigated neurologic finding within the past 12 months.