A single-centre retrospective study of the safety and efficacy of mycophenolate mofetil in children and adolescents with nephrotic syndrome

BACKGROUND The aim of the study was to investigate the efficacy and side effect profile of mycophenolate mofetil (MMF) therapy in children with nephrotic syndrome (NS). METHODS A retrospective case note review was performed on all patients with NS who were commenced on MMF between 1 January 2000 and 31 December 2009 and were followed up for a minimum of 1 year. RESULTS The sample size was 73 patients. The duration of follow-up was for a median of 3.2 years, interquartile range (IQR) (1.7-4.7 years). The median age at diagnosis was 3.2 years, IQR (2.3-5.7 years). The median age of MMF commencement was 11 years, IQR (7.9-13.6 years). There were more boys (67%) than girls. The majority were Caucasian (77%), with 18% Asian 4%, Black Africans and 1% other ethnicities. At initial diagnosis, 61 (84%) were steroid sensitive, 9 (12%) steroid resistant, 3 (4%) steroid dependent (SD). Forty-five (74%) of the 61 steroid-sensitive patients became SD, 4 (7%) of them became steroid resistant, 1 (1%) remained steroid-sensitive and 11 (18%) became frequent relapsers. As to the previous use of second-line immunosuppressants, none were used in 5 (7%) patients, one agent in 17 (23%), two in 27 (37%) and three or more agents were used in 23 (32%) patients. MMF was effective in 45 (62%) patients. Of these, 38 (52%) of them were in remission for >2 years; and in 7 (10%) MMF worked for 1 to 2 years (MMF therapy electively stopped/ongoing). MMF therapy allowed 27 (37%) patients to wean steroids completely and 8 (11%) to achieve complete steroid and immunosuppressant withdrawal. A further 8 (11%) had steroids partially weaned. MMF failures were seen in 13 (18%) within the first year and 5 (7%) in the second year. MMF was stopped due to side effects in 4 (6%) and non-compliance in 4 (6%). The majority of patients had no side effects [51 (70%)]. Seven (9%) had gastrointestinal side effects (diarrhoea/abdominal pain); 5 (7%) had immunological side effects (leucopenia/infections); 3 (4%) had both immunological and gastrointestinal side effects; and 2 (3%) suffered arthralgia. CONCLUSIONS MMF is well tolerated and effective as a second-line agent in treating steroid-sensitive NS. The drug permitted prolonged remission and steroid weaning or other second-line agent withdrawal in a majority of cases.