The purpose of this study is to determine the efficacy and the toxicities of the study drug PD0332991 in the treatment of patients with Stage IV non-small cell lung cancer with wildtype retinoblastoma protein (RB) and inactivated cyclin dependent kinase (CDK) N2A in the tumor.

The oral drug PD0332991 is a highly selective reversible inhibitor of cyclin-dependent kinases 4 & 6 that is being studied for use in the treatment of advanced non-small cell lung cancer.

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

Adverse events were collected from the signing of the Informed Consent Form through 30 days after the last dose of study drug (approximately 20 weeks).

All adverse events were assessed using the results of routine bloodwork, imaging or by a qualified healthcare provider.