Study of Polyphenon E in Men With High-grade Prostatic Intraepithelial Neoplasia

Inclusion Criteria:

* Men with a diagnosis of HGPIN or ASAP in a minimum of 1 of 8 cores from a biopsy performed within six months of study entry. Diagnosis of HGPIN or ASAP (which includes men with ASAP and HGPIN) via trans-rectal ultrasound (TRUS biopsy) is also considered acceptable for inclusion.
* Prostate biopsy with a minimum of 8 cores performed within 6 months of study entry that shows no evidence of cancer.
* 30-80 years of age at the time of registration
* PSA ≤10 ng/ml
* Omnivorous diet
* Eastern Cooperative Oncology Group (ECOG) performance status 0-2
* Participants must have normal organ and marrow function as demonstrated by the following parameters being within normal institutional limits: complete blood count (CBC); liver function tests (LFTs); albumin, total and direct bilirubin, alkaline phosphatase, aspartic transaminase (AST), alanine transaminase (ALT), and total protein), PT/PTT, and LDH; serum creatinine \<1.5 mg/dl or measured creatinine clearance 60 cc/min
* Absence of consumption of toremifene citrate, finasteride, testosterone, dehydroepiandrosterone (DHEA) or other testosterone-like supplements or medications which have known impact on PSA within 30 days of informed consent, or dutasteride within 90 days of informed consent
* Absence of consumption of any nutritional or herbal supplements containing green tea or green tea polyphenols
* No or low regular tea consumption (no more than 3 servings of hot tea or 6 servings of iced tea per week)
* Willing to discontinue current vitamin/mineral supplement use and substitute with a standard multivitamin supplement provided for the study
* Willing to use an effective method of contraception, if the partner is of child-bearing age, while on study
* Willing to comply with proposed visit and treatment schedule
* Able to understand and willing to sign a written informed consent document

Exclusion Criteria:

* Evidence of acute prostatitis or urinary tract infection at the time of PSA measurement; men may be enrolled 30 days after completion of treatment, provided all other eligibility criteria are met
* Current or prior history of prostate cancer or other malignancies (exceptions include non-melanoma skin cancer or other cancer with no evidence of tumor recurrence 5 years after definitive treatment)
* History of renal or hepatic disease, including history of hepatitis B, C or delta
* Participation in any other investigational study or use of any other investigational agents within 30 days of study entry
* History of allergic reactions attributed to tea or other compounds of similar chemical or biologic composition to Polyphenon E or the inactive components present in Polyphenon E and placebo capsules.
* Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or any psychological, familial, sociological or other concomitant condition that would not allow adequate compliance with the study protocol
* History of medical conditions that may predispose the participant to gastrointestinal bleeding (acute or chronic gastritis or colitis, or acute diverticulitis or hemorrhoids)
* Members of all races and ethnic groups are eligible for this trial. Since this is an investigation targeting men with HGPIN or ASAP, women are not eligible for the study.