OBJECTIVES: ADV7103 is a galenic formulation of prolonged-release potassium citrate and potassium bicarbonate granules with a simplified twice-daily dosing regimen that has demonstrated better plasma bicarbonate management in patients with distal renal tubular acidosis (dRTA) than standard of care treatments requiring multiple daily intakes, while maintaining normal plasma potassium levels. If not adequately managed, clinical consequences of dRTA include failure to thrive, progressive kidney function decline and bone complications. Herein, we present the adherence to ADV7103 in a cohort of paediatric and adult patients after 24 months of treatment.

METHODS: Thirty patients with dRTA, including 24 paediatric patients (12-17Y (N=8), 4-11Y (N=13) and 6M-3Y (N=3)), having completed a previous short-term phase II/III study were included in a multi-centre, open-label extension study and received ADV7103. Patients were assessed at baseline (last visit of short-term study) and after 3, 6, 12, 18 and 24 months. Adherence rate was estimated as the proportion of treatment effectively taken compared to the medical prescription and based on study drug delivery and retrieval. Treatment adherence was classed as >90%, 75-90%, 50-74%, or <50%. Laboratory results, and interview of patients/families were supportive in absence of returned treatment.

RESULTS: Adherence rates by 24 months were >90% in 18 (62%) patients, 75-90% in 5 (17%) patients, and 50-74% in the remaining 6 (21%) patients. One patient dropped out after 12 months. Adherence rates of ≥75% were noted in 100% of adults, 63% of adolescents, 85% of children, and 2 out of three toddlers. After 24 months of treatment, average alkali doses were 2.3±1.3; 2.6±1.7; 3.4±1.3 and 4.8 ±2.0 mEq/kg/day in adults, adolescents, children and infants/toddlers, respectively.

CONCLUSIONS: Adherence levels ≥75% were maintained in the majority of patients (79.3%) over 24 months supporting the good acceptance and tolerability of ADV7103 in maintaining long-term metabolic control in patients with dRTA.