Low-dose Selumetinib for the Treatment of Plexiform Neurofibromas in Chinese Children

Inclusion Criteria: * Male and females; * Between 3 and 18 years of age; * Diagnosis of NF1 as determined by meeting at least 2 of the following 7 criteria: (1) six or more cafe-au-lait macules (greater than or equal to 0.5cm in prepubertal subjects or greater than or equal to1.5 cm in post pubertal subjects); (2) two or more neurofibromas (any type); (3) freckling in axilla or groin; (4) optic glioma; (5) two or more Lisch nodules; (6) a distinctive bony lesion (dysplasia of the sphenoid bone or dysplasia or thinning of long bone cortex); (7) a first-degree relative with NF1; * Diagnosis of PN as determined by biopsy and pathological diagnosis; * Complete resection of PN is not feasible without significant morbidity risk; * Normal liver, kidney, and heart function; * Previous treatment, last dose time: colony stimulating factor≥1 week, radiotherapy≥6 weeks, other study drugs\>30 days; * Able to undergo MRI evaluation; * Consent of parents (or the person with parental authority in families): signed and dated written informed consent. Exclusion Criteria: * Patients with contraindications to selumetinib administration (e.g., allergy to selumetinib); * Unable to swallow the entire selumetinib capsule; * Ongoing hormone, immunotherapy, or chemotherapy for PN; * Previously received multiple myelosuppressive chemotherapy regimens; * Suffering from other severe and/or uncontrolled systemic diseases not related to NF1 (e.g., uncontrolled diabetes, hypertension, severe malnutrition…