Efficacy and Safety of Selumetinib in Adults With NF1 Who Have Symptomatic, Inoperable Plexiform Neurofibromas

Key Inclusion Criteria:

* Adults ≥ 18 years at enrollment with diagnosis of NF1 with symptomatic, inoperable PN
* At least one inoperable target PN measurable by volumetric MRI analysis
* Chronic target PN pain score documented for minimum period during screening period
* Stable chronic PN pain medication use at enrollment
* Adequate organ and marrow function

Key Exclusion Criteria:

* Confirmed or suspected malignant glioma or MPNST (low grade glioma, including optic glioma not requiring systemic therapy or radiation therapy are exempt from this exclusion)
* History of malignancy except for malignancy treated with curative intent with no known active disease ≥ 5 years before the first dose of study intervention and of low potential risk for recurrence
* Clinically significant cardiovascular disease, including inherited coronary disease, acute coronary syndrome within 6 months prior to enrollment, uncontrolled angina, symptomatic heart failure, cardiomyopathy, severe valvular heart disease, abnormal LVEF and uncontrolled hypertension
* Ophthalmological findings/conditions including intraocular pressure \> 21 mmHg, RPED/CSR or RVO
* Prior exposure to MEK inhibitors