A Study of Herceptin (Trastuzumab) in Combination With 2nd-Line Chemotherapy in Patients With HER2 Positive Metastatic Breast Cancer.

• Objective response rate, clinical benefit, time to treatment failure, overall survival. [ Time Frame: Event driven ] [ Designated as safety issue: No ]
• AEs, laboratory parameters, LVEF. [ Time Frame: Throughout study ] [ Designated as safety issue: No ]

This 2 arm study will compare the efficacy and safety of continuation or discontinuation of Herceptin treatment in combination with 2nd line chemotherapy, in patients with HER2 positive metastatic breast cancer whose condition has progressed on 1st line chemotherapy plus Herceptin. Patients will be randomized either to continue or discontinue Herceptin treatment (6mg/kg iv infusion every 3 weeks) while receiving second-line chemotherapy of the investigator's choice. The anticipated time on study treatment is until disease progression, and the target sample size is 100-500 individuals.

• Drug: trastuzumab [Herceptin]
  6mg/kg iv every 3 weeks
• Drug: Second line chemotherapy
  As prescribed

• Experimental: 1
  Interventions:

  • Drug: trastuzumab [Herceptin]
  • Drug: Second line chemotherapy
• Active Comparator: 2
  Intervention: Drug: Second line chemotherapy

Inclusion Criteria:

• female patients, >= 18 years of age;
• metastatic breast cancer;
• HER2 overexpression (IHC 3+ and/or FISH positive);
• disease progression during or after previous 1st line chemotherapy + Herceptin;
• scheduled to receive 2nd line chemotherapy.

Exclusion Criteria:

• concurrent immunotherapy or hormonal therapy;
• anthracyclines as part of previous 1st line chemotherapy or planned 2nd line chemotherapy;
• cardiac toxicity during previous 1st line chemotherapy + Herceptin;
• history of other malignancy within last 5 years.