The Primavera study protocol design: evaluating the effect of continuous erythropoiesis receptor activator (C.E.R.A.) on renal function in non-anemic patients with chronic kidney disease.

Erythropoiesis stimulating agents (ESA) are widely used for hemoglobin correction in patients suffering from renal anemia. However, their beneficial non-hematopoietic effects on renal deterioration have not been adequately assessed. The Primavera study is the first prospective, controlled trial to assess whether ESA treatment could ameliorate progression of chronic kidney disease (CKD) in non-anemic patients. Primavera is a single-blind, 24-month trial in which patients are randomized to placebo or to C.E.R.A., a continuous erythropoietin receptor activator. Patients with type 2 diabetes or who have undergone kidney transplantation are eligible to enter the study if they have CKD stage III (estimated GFR [eGFR] 30-59 mL/min/1.73 m(2)), urinary albumin to creatinine ratio (UACR) ≥ 50 g/g and ≤ 1500 g/g, or total urine protein ≥ 50mg/24h and ≤ 1500mg/24h, and hemoglobin 11-14 g/dL. The primary efficacy endpoint is the change in eGFR from baseline to month 24. Secondary efficacy endpoints are the changes in UACR, serum cystatin C and serum creatinine from baseline. Safety endpoints include adverse events and discontinuation due to pre-specified adverse events. An interim analysis will be performed after all patients have completed the first year. The planned sample size is 400 patients (200 type 2 diabetics, 200 transplant recipients) conferring 90% power to detect a prespecified significant difference of 1.5 mL/min/1.73 m(2) in the annual reduction in eGFR between treatment groups. The results of Primavera are expected in 2013.