Losartan for the nephropathy of sickle cell anemia: A phase-2, multicenter trial

Nephropathy is a common and progressive complication of sickle cell anemia (SCA). In SCA mice, we found that hyperangiotensinemia in the absence of hypertension underlies nephropathy, and its downregulation by losartan, an angiotensin-II-receptor-1 blocker, reduced albuminuria and progression of nephropathy. Therefore, we performed a phase-2 trial of oral losartan, given for 6 months, to explore whether it reduced albuminuria in children and adults with SCA. Participants were allocated to groups defined by class of baseline urinary albumin-to-creatinine ratio (UACR): no albuminuria (NoA), microalbuminuria (MicroA), and macroalbuminuria (MacroA). The primary endpoint was a similar to 25% reduction UACR from baseline. There were 32 evaluable participants (mean age 24 years; NoA514, MicroA512, MacroA56). The primary endpoint was met in 83% of the MacroA group (P<0.0001) and 58% of the MicroA group (P<0.0001). Median fold-change in UACR was 20.74 for MacroA and 20.46 for MicroA. In MacroA and MicroA, UACR classification improved in 50% but worsened in 11%. Urine osmolality and estimated glomerular filtration rate (eGFR) did not change significantly. Losartan was discontinued in three participants [leg cramps, N51; decline in eGFR > 25% (142. 104 mL/minute/1.73 m(2)), N51; rise in serum creatinine > 50% (0.2. 0.3 mg/dL), N51]. Albuminuria was associated with diastolic dysfunction and impaired functional capacity, although cardiopulmonary status was unchanged after 6 months of losartan therapy. In summary, losartan decreased urinary albumin excretion in most participants with albuminuria. Those with macroalbuminuria had the greatest benefit. This study forms the basis for a phase-3, randomized, placebo-controlled trial of losartan for the nephropathy of SCA.