GW572016 Combined With Trastuzumab For The Treatment Of Previously Trastuzumab-Treated Breast Cancer

Phase I Study of Lapatinib in Combination With Trastuzumab

This is two-part study (Phase I/Phase II). Part I is designed to find the optimal (best) doses of GW572016 and trastuzumab when given together,Part II is designed to evaluate the tumor response rate (shrinkage or lack of growth) in patients receiving lapatinib and trastuzumab.

Inclusion criteria:

• Patients with confirmed breast cancer who have received prior trastuzumab.
• Patients must have adequate blood, liver, and kidney function and either be fully active or restricted only in performing strenuous activity.
• Female patients of child-bearing potential must be willing to abstain from intercourse from 2 weeks prior to administration of the first dose of study medication until 28 days after the final dose of study medication or be willing to consistently and correctly use an acceptable method of birth control.

Exclusion criteria:

• Patients with certain heart problems.