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