Qol-05. Memantine for Prevention of Cognitive Late Effects in Children Receiving Cranial Radiation Therapy for Focal Brain Tumors: A Pilot Study

Abstract BACKGROUND Childhood brain tumor survivors treated with cranial irradiation are at significant risk for cognitive late effects that negatively impact quality of life. Memantine (an NMDA receptor antagonist), taken during radiotherapy for brain metastases in adults, resulted in reduced cognitive declines. This is the first investigation of feasibility, acceptability, and preliminary efficacy of memantine for reducing cognitive late effects in children undergoing radiation therapy. METHODS In a randomized, double-blind, controlled trial (MEMCRT; NCT03194906) children took memantine (20 mg/d) or placebo for 12 weeks. During the medication phase, participants received weekly phone calls to assess adherence using pill counts and monitor side effects using the SAFTEE structured interview. At baseline, 6 weeks (end of radiation therapy), and 12 weeks (end of medication), participants completed a brief battery of cognitive measures. RESULTS 30 patients (age at irradiation=11.93±2.87; 47% male) were included; memantine (n=16) and placebo (n=14) groups did not differ in age, sex, race, socioeconomic status or baseline IQ (ps.26). Study participation (71% of those approached) and medication adherence (88% completed 12 weeks, with 97% of medication taken) were high. Side effects were minimal (only one CTCAE≥ 3; headache in the placebo group) with no difference between groups in change in side effect severity from baseline to any medication week, across any symptom inquiry (ps.23). At 12 weeks, Cohen’s d effect sizes (ES) indicate the memantine group had better performance on measures of processing speed (Cogstate Identification ES=.61), academic fluency (Woodcock Johnson-IV Reading Fluency ES=.45; Math Fluency ES=.81), and fatigue (PedsQL Multidimensional Fatigue Scale ES=.72). CONCLUSIONS Study findings indicate memantine used as a neuroprotectant during radiation therapy for children with focal brain tumors is feasible and acceptable, with preliminary evidence for better cognitive outcomes that require validation in a larger, definitive trial.