As part of a post-approval commitment, the Korean health authority requests a study to characterize safety and effectiveness in patients treated with Koselugo (Selumetinib), an oral selective inhibitor of MAPK kinase (MEK) 1 and 2, by physicians in routine clinical practice settings. This study is designed to assess the known safety profile or identify previously unsuspected adverse reactions and evaluate the effectiveness of Koselugo under conditions of routine daily medical practice in Korea.

This study will provide information on the Korean patient population that is treated with the study drug.

Inclusion Criteria:

1. Patients treated with Koselugo (Selumetinib) under the approved label in South Korea
2. Provision of signed and dated written informed consent by the patient or legally acceptable representative

Exclusion Criteria:

1. Patients treated with Koselugo (Selumetinib) under the approved label in South Korea
2. Provision of signed and dated written informed consent by the patient or legally acceptable representative

Patients treated with Koselugo (Selumetinib) under the approved label in South Korea.

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal Vivli.org. All requests will be evaluated as per the AZ disclosure commitment:

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure. "Yes", indicates that AZ are accepting requests for IPD, but this does not mean all requests will be approved.

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA/PhRMA Data-Sharing Principles. For details of our timelines, please refer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

When a request has been approved AstraZeneca will provide access to the anonymized individual patient-level data via secure research environment Vivli.org. A Signed Data Usage Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information.