Mycophenolate mofetil in paediatric autoimmune or immune-mediated diseases of the central nervous system: clinical experience and recommendations

Abstract

Aim: To gather data on mycophenolate mofetil (MMF) in paediatric autoimmune/immune-mediated central nervous system (CNS) conditions, focusing on safety and factors that may affect MMF efficacy. Method: Retrospective, multicentre study based on four paediatric neurology centres. Results: Forty-four children were included (30 females, 14 males): 19 had proven/suspected autoimmune encephalitis, 14 had inflammatory demyelinating CNS diseases, and 11 had other autoimmune/immune-mediated CNS conditions. Before MMF, all received first-line immune therapies, and 17 had second-line rituximab and/or cyclophosphamide. MMF was started at a median of 9.5 months from disease onset (range 1–127mo) (median age 9y 4mo, range 1y 5mo–16y 5mo), and was used for median 18 months (range 0.3–73mo). On MMF, 31 patients were relapse-free, whereas eight relapsed (excluding patients with chronic–progressive course). Relapses on MMF were associated with medication weaning/cessation, or with suboptimal MMF dosage/duration. Adverse events of MMF occurred in eight patients: six moderate (gastrointestinal, movement disorder, dermatological) and two severe (infectious). Interpretation: MMF use in paediatric neuroimmunology is heterogeneous, although relatively safe. We have identified factors that may affect MMF efficacy and provide recommendations on MMF usage. What this paper adds: Mycophenolate mofetil (MMF) use was heterogeneous with relatively common adverse events, although mostly not severe. MMF treatment reduced median annualized relapse rate, although 20% of patients relapsed on MMF. A high relapse rate pre-MMF and late MMF start were associated with higher probability of relapsing on MMF. Most relapses were associated with suboptimal MMF dosage, short MMF duration, or concurrent medication weaning/discontinuation.