Key Inclusion Criteria:

        Patients must meet all of the following criteria to be eligible for enrollment in the
        study.

          -  Histologically confirmed diagnosis of locally advanced, unresectable or metastatic
             cutaneous melanoma or unknown primary melanoma American Joint Committee on Cancer
             Stage IIIB, IIIC, or IV.

          -  Presence of BRAF V600E or V600K mutation in tumor tissue as determined by a local or
             central laboratory

          -  Adequate cardiac function:

               -  Left ventricular ejection fraction (LVEF) ≥ 50% as determined by ECHO or
                  multi-gated acquisition (MUGA) scan and above the institutional lower limit of
                  normal (LLN);

               -  Triplicate average baseline QTcF value ≤ 450 ms.

          -  Adequate bone marrow, organ function, and laboratory parameters:

               -  Absolute neutrophil count (ANC) ≥ 1.5 × 10⁹/L;

               -  Hemoglobin ≥ 9 g/dL with or without transfusions;

               -  Platelets ≥ 75 × 10⁹/L without transfusions;

               -  Aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) ≤ 2.5 ×
                  upper limit of normal (ULN); in patients with liver metastases ≤ 5 × ULN;

               -  Total bilirubin ≤ 1.5 × ULN;

               -  Creatinine ≤ 1.5 × institutional ULN for age, or calculated creatinine clearance
                  ≥ 70 mL/min/1.73 m² (following Schwartz formula).

          -  Adequate performance status at Screening:

               -  Patients < 16 years old: Lansky Performance Scale score ≥ 80

               -  Patients 16 to 17 years old: Karnofsky Performance Scale score ≥ 80

        Key Exclusion Criteria:

        Patients meeting any of the following criteria are not eligible for enrollment in the
        study.

          -  Uveal or mucosal melanoma.

          -  Brain metastases that are uncontrolled or symptomatic, require steroids, are
             potentially life-threatening or have required radiation within 28 days prior to
             starting study drug.

          -  History or current evidence of retinal vein occlusion (RVO) or current risk factors
             for RVO

          -  Prior therapy with a BRAF inhibitor (e.g., dabrafenib, vemurafenib) and/or a MEK
             inhibitor (e.g., trametinib, cobimetinib).

          -  Impaired cardiovascular function or clinically significant cardiovascular disease,
             including any of the following:

               -  History of acute coronary syndromes (including myocardial infarction, unstable
                  angina, coronary artery bypass grafting, coronary angioplasty or stenting) < 6
                  months prior to screening,

               -  Symptomatic chronic heart failure, history or current evidence of clinically
                  significant cardiac arrhythmia and/or conduction abnormality < 6 months prior to
                  screening except atrial fibrillation and paroxysmal supraventricular tachycardia.

          -  Concurrent neuromuscular disorder associated with elevated creatine kinase (CK)

          -  Uncontrolled arterial hypertension despite medical treatment

          -  Presence of BRAFʷͭ or indeterminate melanoma in tumor tissue.