SIKAMIC (SIklos on Kidney Function and AlbuMInuria Clinical Trial) (SIKAMIC)

Inclusion Criteria:

1. Signed and dated Informed Consent Form (ICF) by a legally competent patient.
2. Patients above 18 years.
3. Patients with HbSS or HbSβ0 SCD.
4. Patients with a value of albuminuria, assessed by ACR, over 3 mg/mmol and inferior to 100 mg/mmol confirmed by 3 positive urine samples taken one day apart.
5. Female patients of childbearing potential or postmenopausal female with last period < 12 months before screening agreeing to use a highly effective form of contraception (oral, injected or implanted hormonal contraception, intrauterine device, diaphragm, condom) during the trial and for 3 months after hydroxycarbamide discontinuation.
6. Male patients with partners of childbearing potential agreeing to use a highly effective contraception during the trial and for 3 months after hydroxycarbamide discontinuation. Men with pregnant or lactating women should be advised to use a barrier method of contraception (condom) to prevent the foetus or breastfed infant from exposure to hydroxycarbamide.
7. Patients who are covered by insurance scheme according to local regulatory requierements.

Exclusion Criteria:

1. Patients who had severe VOC requiring hospitalisation or ACS within the last 4 weeks preceding screening visit.
2. Patients treated with hydroxycarbamide for any reason within the previous 6 months.
3. Patients who have had chronic blood transfusion or transfusion in the last 3 months.
4. Patients with a history of hypertension (systolic blood pressure ≥ 140 or diastolic blood pressure ≥ 90 mmHg) treated with antihypertensive agent belonging to pharmacological class of RAS inhibitor.
5. Patients who have symptoms suggestive of urinary tract infection or patients with gross haematuria.
6. Patients with a concomitant primary kidney disease.
7. Patients with any systemic condition that could result in a glomerulopathy not related to SCD (e.g. diabetes mellitus, active hepatitis B or C infections, HIV infection, systemic lupus erythematosus, inflammatory arthropathies).
8. Patient with a stage 3, 4 or 5 chronic kidney disease (eGFR < 60 mL/min per 1.73 m2).
9. Patients with eGFR ≥ 140 ml/min/1,73m² due to the lack of information regarding the magnitude, direction and significance of the trends in eGFR evolution that could be expected in this population
10. Patients requiring long-term treatment with drugs potentially nephrotoxic (see non-exhaustive list).
11. Patients requiring ACE inhibitors or ARBs within the 3 months before inclusion regardless of the indication.
12. Patients requiring long-term treatment with non-steroid anti-inflammatory drugs.
13. Patients who have a treatment which can modify the kidney function (see non-exhaustive list) in the last 3 months.
14. Patients known to be infected with HIV.
15. Female patients who are pregnant or lactating.
16. Unreliable patients including non-compliant patients, patients with known alcoholism or drug abuse or with a history of a serious psychiatric disorder as well as patients unwilling to give informed consent or to abide by the requirements of the protocol.
17. Simultaneous participation in other clinical trials on an investigational medicinal product or previous participation within 30 days before inclusion.
18. Persons in detention by judicial or administrative decision.
19. Patients with chronic conditions that upon investigator judgment may lead to a limited life expectancy