RecruitingDrug trialPASS of Xromi Comparing Safety and Effectiveness in Children Under 2 Years With Sickle Cell Disease [PRECISE PASS]This post-authorisation safety and efficacy study (PRECISE PASS) evaluates the use of Xromi® (hydroxycarbamide 100 mg/mL oral solution) in children aged 9 months to under 2 years with sickle cell disease (SCD). The objective is to assess the safety profile and clinical effectiveness of Xromi® under routine clinical conditions. The study includes a prospective cohort of Xromi®-treated patients and a matched retrospective comparator cohort of untreated patients. Participants will be followed for 24 months from treatment initiation or matched index date.