Inclusion Criteria:

          -  Pathologic evidence of advanced stage IV or recurrent lung adenocarcinoma reviewed at
             MSKCC

          -  Somatic activating mutation in EGFR Radiographic progression during treatment with
             erlotinib.

          -  Any number of prior chemotherapy regimens is permitted.

          -  Measurable (RECIST 1.1) indicator lesion not previously irradiated

          -  KPS >/= 70%

          -  Age >18 years old

          -  Must have undergone biopsy after development of acquired resistance to erlotinib with
             available archived tissue (equivalent of > 10 unstained slides)

          -  Left ventricular Ejection Fraction >/= the lower limit of normal by ECHO or MUGA

          -  Adequate organ function:

          -  AST, ALT </= 2.5 x ULN

          -  Total bilirubin </= 1.5 x ULN

          -  Albumin>/=2.6g/dL - Creatinine < 1.5 x ULN OR calculated creatinine clearance
             >/=50mL/min

          -  Absolute neutrophil count (ANC) >/= 1,200 cells/mm3

          -  Hemoglobin>/=9.0 g/dL

          -  Platelets >/=100,000/mm3

        Exclusion Criteria:

          -  Patients with symptomatic brain metastasis requiring escalating doses of steroids

          -  Patients with grade 2 or greater diarrhea prior to study initiation despite maximal
             medical management due to medications or a medical condition such as Crohn's disease
             or malabsorption

          -  Pregnant or lactating women

          -  Any type of systemic therapy (chemotherapy or experimental drugs) within 2 weeks of
             starting treatment on protocol except for a EGFR TKI

          -  Patients who have received prior treatment with a MEK inhibitor

          -  Any major surgery or extensive radiotherapy within 21 days of starting treatment on
             protocol.

          -  A history of clinically significant interstitial lung disease or pneumonitis

          -  Clinically significant cardiac disease including unstable angina, acute myocardial
             infarction within 6 months from Day 1 of study administration, New York Heart
             Association Class III or IV congestive heart failure, or symptomatic uncontrolled
             Arrythmias, prolonged corrected QT interval >480msec, treatment refractory
             hypertension, presence of a cardiac defibrillator

          -  History of central serous retinopathy or retinal vein occlusion