Oral Drug Study In Women With Refractory Metastatic Breast Cancer After First-line or Second-line Herceptin.

Inclusion Criteria: (The patient must meet the following criteria in order to be eligible for this study.)

* Signed informed consent
* No more than two prior regimens for metastatic breast cancer. Each regimen must have contained Herceptin.
* Refractory Stage IIIb or IV breast cancer
* HER2/neu tumor overexpression
* Disease progression while receiving a prior chemotherapy regimen with Herceptin alone or in combination with other chemotherapy.
* Tumor tissue available for testing.
* 2 weeks since treatment with Herceptin (alone or in combination).
* Able to swallow and retain oral medication
* Cardiac ejection fraction within the institutional range of normal as measured by MUGA (Multiple Gated Acquisition Scan).
* Adequate kidney and liver function
* Adequate bone marrow function

Exclusion Criteria: (The patient cannot meet any of the following criteria in order to be eligible for this study.)

* Prior regimens did not include Herceptin.
* Pregnant or lactating.
* Conditions that would affect absorption of an oral drug
* Serious medical or psychiatric disorder that would interfere with the patient's safety or informed consent.
* Severe cardiovascular disease or cardiac disease requiring a device.
* Active infection.
* Brain metastases.
* Concurrent cancer therapy or investigational therapy.
* Use of oral or IV steroids.
* Unresolved or unstable serious toxicity from prior therapy.
* Treatment with EGFR (Endothelial Growth Factor Receptor) inhibitor other than Herceptin.