Inclusion Criteria:

- Patients must have histologically or cytologically confirmed prostate cancer that is
recurrent after local therapy, and/or metastatic carcinoma confirmed to be of
prostate origin

- Patients must have recurrent and/or metastatic disease that is progressive and not
amenable to surgery or curative radiotherapy; progressive disease is defined as:

- Three consecutive rising PSAs, at least 4 weeks apart with an absolute increase
of at least 0.5

- PSA doubling time of less than one year

- PSA > 2.0

- For recurrent disease following local therapy (surgery/radiation), prior neoadjuvant
or adjuvant hormones are allowed if completed more than a year prior to study entry;
for metastatic disease, no prior medical therapy (hormonal, corticosteroid,
chemotherapy) is allowed

- Life expectancy of greater than 12 weeks

- ECOG performance status 0,1, or 2

- Leukocytes >= 3,000/uL

- Absolute neutrophil count >= 1,500/uL

- Platelets >= 100,000/uL

- Total bilirubin within normal institutional limits

- AST(SGOT)/ALT(SGPT) =< 2.5 X institutional upper limit of normal

- Creatinine within normal institutional limits or creatinine clearance >= 60
mL/min/1.73 m^2 for patients with creatinine levels above institutional normal

- Cardiac ejection fraction within the institutional range of normal as measured by
echocardiogram or MUGA scan; note that baseline and on treatment scans should be
performed using the same modality and preferably at the same institution

- Must be willing and able to undergo tumor biopsy once before (if no previous specimen
available) and once during investigational therapy if there are lesions accessible
for biopsy for correlative studies; in cases where there is a medical
contraindication to tumor biopsy, exception may be granted only upon discussion with
the principal investigator

- Eligibility of patients receiving medications or substances known to affect, or with
the potential to affect the activity or pharmacokinetics of GW572016 will be
determined following review of their use by the principal investigator

- Patients requiring oral anticoagulants (coumadin, warfarin) are eligible provided
there is increased vigilance with respect to monitoring INR

- Women of child-bearing potential and men must agree to use adequate contraception
(hormonal or barrier method of birth control or abstinence) prior to study entry and
for the duration of study participation; should a woman become pregnant or suspect
she is pregnant while participating in this study, she should inform her treating
physician immediately

- Ability to understand and the willingness to sign a written informed consent document

- Able to swallow and retain oral medication

Exclusion Criteria:

- Prior treatment:

- Patients who have had prior chemotherapy for prostate cancer

- Patients who have been on androgen ablative therapies within the last year

- Patients receiving radiotherapy to the prostate less than 6 weeks prior to study
entry

- Patients who have had prior treatment with EGFR targeting therapies

- Patients who have not recovered from adverse events due to agents administered
more than 4 weeks earlier

- Patients may not be receiving any other investigational agents or receiving
concurrent anticancer therapy

- Patients with a history of other active malignancy in the past 5 years (with the
exception of adequately treated non-melanomatous skin cancers) are excluded

- History of allergic reactions attributed to compounds of similar chemical or
biological composition to GW572016

- Uncontrolled intercurrent illness including, but not limited to, ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia, or psychiatric illness/social situations that would limit compliance with
study requirements

- Patients with cardiac ejection fraction, not within the institutional range of normal
as measured by echocardiogram or MUGA scan at baseline

- Patients with GI tract disease resulting in an inability to take oral medication,
malabsorption syndrome, a requirement for IV alimentation, prior surgical procedures
affecting absorption, uncontrolled inflammatory GI disease (e.g., Crohn's, ulcerative
colitis)

- Concomitant requirement for medication classified as CYP3A4 inducer or inhibitor