Study of Selective BRAF Kinase Inhibitor Dabrafenib Monotherapy Twice Daily and in Combination With Dabrafenib Twice Daily and Trametinib Once Daily in Combination Therapy in Subjects With BRAF V600E Mutation Positive Metastatic (Stage IV) Non-small Cell Lung Cancer.

Inclusion Criteria

• Signed written informed consent;
• Histologically or cytologically confirmed non-small cell cancer of the lung (NSCLC) stage IV (accordingto AJCC Staging 7th Edition);
• For Cohorts A and B, documented tumor progression (based on radiological imaging) after receiving at least one prior approved platinum-based chemotherapy regimen for advanced stage/metastatic NSCLC. An alternate chemotherapeutic agent/regimen is an acceptable substitute in the event that the subject was intolerant to, or ineligible to receive platinum based chemotherapy. Subjects enrolled in Cohort B cannot have more than 3 prior systemic treatments for advanced stage/metastatic NSCLC (neoadjuvant and adjuvant therapies are not counted in number of prior regimens and maintenance therapy is not counted as a separate regimen). Subjects in Cohort C will be required to have not received prior systemic anti-cancer therapies for metastatic disease (i.e., dabrafenib/trametinib will be 1st line treatment for metastatic disease);
• Measurable disease according to Response Evaluation Criteria in Solid Tumors [RECIST 1.1];
• At least 18 years of age;
• Anticipated life expectancy of at least three months;
• Presence of a BRAF V600E mutation in lung cancer tissue. Mutation must be locally confirmed in a CLIA-certified laboratory (or equivalent). An adequate amount of tumor tissue (archived tumor tissue, or fresh biopsy if archived tissue is not available) must be available at the time of enrolment for central validation of BRAF mutation;
• Able to swallow and retain oral medication;
• Women of childbearing potential must have a negative serum pregnancy test within 14 days before the first dose of study treatment and agree to use effective contraception during the study; NOTE: Oral contraceptives are not reliable due to potential drug-drug interaction with dabrafenib.
• Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-2;
• Must have adequate organ function as defined by the following baseline values:

Absolute neutrophil count (ANC) >/=1.5x10^9/L Hemoglobin >/=9 g/dL Platelets >/=100x10^9/L Prothrombin time /International normalized ratio (INR) and partial thromboplastin time 1.5 mg/dL, calculate creatinine clearance using standard Cockcroft and Gault; creatinine clearance must be > 50 mL/min); creatinine clearance should be >/= 50 mL/min Left ventricular ejection fraction >/= institutional lower limit of normal ECHO

• French subjects: In France, a subject will be eligible for inclusion in this study only if either affiliated to or a beneficiary of a social security category
• Previously tested for presence of EGFR and ALK mutations in lung cancer tissue confirmed in a CLIA-certified laboratory (or equivalent). Subjects with EGFR or ALK mutation are eligible if they have previously received EGFR or ALK inhibitor(s) respectively.

Exclusion Criteria

• Previous treatment with a BRAF inhibitor (including but not limited to dabrafenib, vemurafenib, LGX818, and XL281/BMS-908662) or MEK inhibitor (including but not limited to trametinib, AZD6244, and RDEA119) prior to start of study treatment (Note: Prior treatment with dabrafenib is allowed for crossover subjects in Cohort A);
• Anti-Cancer therapy including chemotherapy, radiation-therapy, immunotherapy, biologic therapy or major surgery within 14 days prior to start of study treatment (Note: Dabrafenib monotherapy within 14 days prior to starting combination therapy is allowed for crossover subjects in Cohort A);
• Use of any investigational anti-cancer drug within 14 days or 5-half-lives (minimum 14 days), prior to start of study medication (Note: Dabrafenib monotherapy within 14 days prior to starting combination therapy is allowed for crossover subjects in Cohort A);
• Current use of a prohibited medication or expected to require any of these medications during treatment with study treatment.
• Unresolved toxicity of National Cancer Institute Common Terminology Criteria for Advers