Cyclin Dependent Kinase (CDK)4/6 Inhibitor, PD0332991 in Advanced Non-small Cell Lung Cancer NSCLC.

Inclusion Criteria: * Histologically or cytologically proven non small cell lung cancer * Stage IV (M1a or M1b) disease. Patients may also have recurrence of early-stage disease or locally advanced disease with the presence of new distant metastases. * Cyclin dependent kinase (CDK)N2a (p16) protein absent or expressed at a low level in tumor biopsy specimen * Failed or intolerant of at least one prior systemic chemotherapy regimen (there is no maximum number of prior chemotherapy regimens) * Eastern cooperative oncology group (ECOG) performance status 0-2 * Age \>18 years. * Adequate organ and bone marrow function * Measurable disease by standard RECIST v1.1 criteria * Life expectancy of greater than 3 months Exclusion Criteria: * Inability to understand or sign the informed consent document * Inability or unwillingness to take oral medications * No available tissue specimen for p16 analysis * Chemotherapy or radiotherapy within 3 weeks prior to beginning the study drug * Other investigational agents within 4 weeks prior to beginning the study drug * All side effects from previous chemotherapy, radiotherapy or investigational agents not resolved, returned to baseline or returned to Grade 1 toxicity (exceptions are grade 2 alopecia and grade 2 peripheral neuropathy) * Major surgery within 4 weeks prior to beginning the study drug * Surgical scar from previous surgery not healed prior to beginning the study drug * High-dose or chronic steroid use * High-dose statins within 7 days * History of rhabdomyolysis * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, uncontrolled diabetes, stroke or myocardial infarction within 3 months, or psychiatric illness/social situations that would limit compliance with study requirements. * Baseline corrected QT interval (QTc) \>470ms * Pre-existing clinically significant cardiac, hepatic or renal dysfunction at the discretion of the treating physician * Untreated or uncontrolled (symptomatic or asymptomatic) brain metastases * Leptomeningeal carcinomatosis * Inability or unwillingness to use contraception during the treatment period by patients with reproductive potential. * Pregnant or breastfeeding women * HIV-positive patients on combination antiretroviral therapy