A Study of Selumetinib in Chinese Paediatric and Adult Subjects With Neurofibromatosis Type 1 (NF1) and Inoperable Plexiform Neurofibromas (PN)

Inclusion Criteria:

* Paediatric cohort: Chinese subjects ≥3 years and \<18 years of age
* Adult cohort: Chinese subjects ≥18 years of age at the time of study enrollment
* Subjects must be diagnosed with (i) NF1 as per NIH Consensus Development Conference Statement and（ii) PN is defined as a neurofibroma that has grown along the length of a nerve and may involve multiple fascicles and branches. (iii) inoperable PN
* Subjects must have at least one measurable typical or nodular PN
* Absolute neutrophil count ≥1.5×10\^9/L, haemoglobin ≥9g/dL, and platelet count ≥100×10\^9/L. Subject must be without growth factor support and platelet transfusion support 7 days before the screening assessment.
* Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2×upper limit of normal (ULN), total bilirubin ≤1.5×ULN except in the case of subjects with documented Gilbert's disease (≤2.5×ULN).

Exclusion Criteria:

* Evidence of malignant peripheral nerve sheath tumour.
* Clinically significant cardiovascular disease
* Prior malignancy (except for adequately treated basal cell or squamous cell skin cancer, in situ cervical cancer, or other cancer from which the subject had been disease free for ≥2 years or which would not have limited survival to \<2 years) or other cancer requiring treatment with chemotherapy or radiation therapy.
* Subjects with the following ophthalmological findings/conditions:

Current or past history of retinal pigment epithelial detachment/central serous retinopathy or retinal vein occlusion; Intraocular pressure \>21 mmHg (or ULN adjusted by age) or uncontrolled glaucoma (irrespective of IOP); Subjects with known glaucoma and increased IOP who do not have meaningful vision (light perception only or no light perception) and are not experiencing pain related to the glaucoma, may be eligible after discussion with the study physician; Any other significant abnormality on ophthalmic examination that would make the subject unsuitable for enrolment into the study, as assessed by the investigator.