Pilot Study of Mycophenolate Mofetil for Treatment of Kidney Disease due to Congenital Urinary Tract Disorders in Children

Background

Congenital uropathies account for nearly half the chronic kidney disease in children. Immune-mediated injury may contribute to progressive loss of kidney function in affected patients.

Study Design

Open-label uncontrolled pilot study to determine the feasibility of treatment with the immunosuppressive drug mycophenolate mofetil (MMF) to prevent a decrease in kidney function in pediatric patients with congenital uropathies.

Setting & Participants

Children treated in an outpatient tertiary-care center were eligible if they had: (1) age of 3 to 16 years, (2) glomerular filtration rate (GFR) less than 50 mL/min/1.73 m², and (3) a congenital genitourinary tract abnormality.

Intervention

After a 2-month run-in period, patients were prescribed MMF, 600 mg/m²/dose, twice daily for a 24-month treatment period.

Outcomes

The primary end point was feasibility based on the ability to recruit and retain subjects and lack of unanticipated adverse events. The secondary end point was change in GFR.

Measurements

Patients were monitored by using standard clinical laboratory tests, and GFR was determined by means of iothalamate clearance.

Results

12 patients aged 8.9 ± 4.8 years (10 boys, 2 girls) were treated with MMF for 18.6 ± 8.0 months; 7 patients completed the entire treatment period. MMF dosage at the final study visit was 381 ± 241 mg/m² twice daily. Gastrointestinal symptoms were the most common adverse effect. There was only 1 serious adverse event, an episode of fever and neutropenia requiring parenteral antibiotic therapy after 21 months of MMF therapy. GFR remained stable throughout the treatment period. Nutritional status, blood pressure, and serum calcium, phosphorus, and cholesterol levels were unchanged during this period.

Limitations

Insufficient power to assess the safety or efficacy of MMF therapy for patients with congenital uropathies.

Conclusion

It is feasible to study MMF as an adjunctive therapy to retard the progression of kidney disease in children with congenital uropathies. A multicenter randomized clinical trial is warranted to determine the efficacy of this novel treatment strategy.

Index Words: Mycophenolate mofetil, congenital uropathies, disease progression, iothalamate