RATIONALE: PD 0332991 may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth.

PURPOSE: This phase II trial is studying the side effects and how well PD 0332991 works in treating patients with refractory solid tumors.

PRIMARY OBJECTIVES:

I. To determine the response rates following treatment with PD 0332991 in the following malignancies: 1) Metastatic breast cancer, 2) Metastatic colorectal cancer, 3) Metastatic melanoma with CDK4 mutation or amplification, or 4) Cisplatin-refractory, unresectable germ cell tumors.

OUTLINE:

Patients receive oral PD 0332991 once daily on days 1-21. Treatment repeats every 28 days for up to 12 courses in the absence of unacceptable toxicity or disease progression.

Inclusion Criteria:

- Disease Characteristics:

All Subjects: All subjects treated under this protocol will have histologically documented cancer of one of the following types:

A. Metastatic breast cancer (7 triple negative, 23 ER+ after the first 15 patients are enrolled on the non-CCND1cohort; in addition 10 HER2+ for combination trastuzumab and PD0332991 therapy) up to 55 total enrollment slots B. Metastatic colorectal cancer that harbors the Kras or BRAF mutation (15-30 enrollment slots) C. Advanced or metastatic esophageal and/or gastric cancer (15-30 enrollment slots) D. Cisplatin-refractory, unresectable germ cell tumors (15-30 enrollment slots) E. Any tumor type if tissue tests positive for CCND1 amplification, CDK4/6 mutation, CCND2 amplification OR any other functional alteration at the G1/S checkpoint. (15-30 enrollment slots)

- Biopsy Requirements: For Subjects with accessible disease amenable to biopsy: A biopsy will be obtained pre-treatment and in during cycle 1 (while patient is receiving drug) for molecular markers of the cell cycle, and its inhibition.

• Subjects will be > 18 years old
• The subject has disease that is assessable by tumor marker, physical, or radiologic means.
• The subject has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• The subject has adequate organ function, defined as follows A. Bilirubin ≤ 1.5 x the upper limit of normal (ULN) B. Serum creatinine ≤ 1.5 x UNL or calculated creatinine clearance ≥ 60 mL/min, and C. For subjects without liver metastases: alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 x ULN D. For subjects with liver metastases: alanine aminotransferase (ALT) and aspartate aminotransferase ≤ 5 x ULN
• All tumors must test positive for Rb expression except:

A. ER positive metastatic breast tumors (data now shows all to be Rb positive.) B. Any tumor type if tissue tests positive for CCND1 amplification, CDK4/6 mutation, CCND2 amplification OR any other functional alteration at the G1/S checkpoint.

- The subject has adequate marrow function, defined as follows: A. Absolute neutrophil count (ANC) >1500/mm3 B. Platelets >100,000/mm3, and C. Hemoglobin > 9 g/dL

• The subject is capable of understanding and complying with the protocol requirements and has signed the informed consent document.
• Sexually active subjects (male and female) must use accepted methods of contraception during the course of the study and for 3 months after the last dose of protocol drug(s).
• Female subjects of childbearing potential must have a negative pregnancy test at screening. Females of childbearing potential are defined as sexually mature women without prior hysterectomy or who have had any evidence of menses in the past 12 months.
• However, women who have been amenorrheic for 12 or more months are still considered to be of childbearing potential if the amenorrhea is possibly due to prior chemotherapy, antiestrogens, or ovarian suppression.

Exclusion Criteria

• The subject has received cytotoxic chemotherapy (including investigational cytotoxic chemotherapy) within 3 weeks (or nitrosoureas or mitomycin C within 6 weeks) before the first dose of PD 0332991. . Patients with HER2-overexpressing tumors may receive trastuzumab up to the date of starting therapy, and may continue to receive trastuzumab while receiving PD0332991.

• The subject has received any other type of investigational agent within 28 days before the first dose of study treatment.

• The subject has not recovered from clinically-meaningful toxicity due to prior therapy (i.e., back to baseline or Grade ≤ 1), with the exception of neurotoxicity and alopecia.

• The subject has untreated or uncontrolled brain metastases or evidence of leptomeningeal involvement of disease unless the subject has a teratoma in which case s/he may be eligible if all other eligibility criteria are met

• The subject has uncontrolled intercurrent illness including, but not limited to:

  1. ongoing or active infection
  2. diabetes mellitus
  3. hypertension
  4. symptomatic congestive heart failure, unstable angina pectoris, stroke or myocardial infarction within 3 months

• The subject has a baseline corrected QT interval (QTc) > 470 ms.

• The subject is pregnant or breastfeeding.

• The subject is known to be positive for the human immunodeficiency virus (HIV). Note:

baseline HIV screening is not required

- The subject is unable or unwilling to abide by the study protocol or cooperate fully with the investigator or designee.