INNV-13. OPHTHALMOLOGICAL COMPLICATIONS IN NF-1 PATIENTS RECEIVING MEK INHIBITORS: MD ANDERSON CANCER CENTER EXPERIENCE

Abstract BACKGROUND MEK inhibitors (MEKi) are a novel therapy for plexiform neurofibromas and optic gliomas in Neurofibromatosis type 1 (NF1). Potential ophthalmic complications are MEKi-induced retinopathy (MEKAR) requiring regular ophthalmologic assessments. We assess the importance of screening and ocular adverse events (OAE) in pediatric NF1 patients receiving MEKi. METHODS We reviewed 45 NF1 patients with baseline and follow-up examinations before and post MEKi treatment initiation. Evaluations included comprehensive eye examination, visual acuity, dilated fundoscopic examination, optical coherence tomography (OCT) of the macula and nerve fiber layer, and Humphrey visual field testing. RESULTS Twenty-six (62% male) of 45 patients were included. Median age at treatment was 15 (range 2-23) years. Plexiform neurofibromas were the most common indication for MEKi (n=22). Selumetinib was the most common MEKi (n=19, 77%), then trametinib (n=6, 23%), and mirdametinib (n=1, 4%). Only two patients had to switch to different MEKi. Patients were followed for a mean of 413-days after treatment initiation (range 103-1122 days) for an average of 3.85 ophthalmology exams per patient. No retinopathy was observed at each of the 3–6 month follow-ups. Around 15% of patients experienced dry eye symptoms with none requiring artificial tears for management. Seven patients had pre-existing optic neuropathy. No dose adjustments were needed due to OAEs. One patient’s visual acuity decreased temporarily but returned to baseline and the patient remains on MEKi. CONCLUSIONS Regular ophthalmologic assessments are crucial for NF1 patients undergoing MEKi treatment. Consensus guidelines on frequency of ophthalmologic screening during MEKi treatment are not well reported. In our cohort no patients had MEKAR at regular 3–6 month follow ups. In addition to baseline screening, future larger cohort studies are needed to confirm if decreasing the frequency of retinal exams is safe while on MEKi to inform future clinical screening guidelines for NF1 patients on MEKi.