Combination of AUY922 With Trastuzumab in HER2+ Advanced Breast Cancer Patients Previously Treated With Trastuzumab

The phase Ib part of the trial will assess the MTD of AUY922 in combination with Trastuzumab
in patients with Trastuzumab-refractory locally advanced or metastatic HER2+. The MTD is
defined as the highest drug dosage not causing in the first cycle of treatment (28 days)
medically unacceptable dose limiting toxicity (DLT).

The phase II part of the trial will assess any potential effect on efficacy of adding AUY922
to Trastuzumab in patients with Trastuzumab-refractory locally advanced or metastatic HER2+
breast cancer.

Both AUY922 and Trastuzumab will be administered as a weekly IV infusion. Treatment should
be continued as long as the patient does not have disease progression and tolerates the
treatment. The following reasons are examples of acceptable reasons for discontinuing the
study; tumor progression (by RECIST, as assessed by the investigator), unacceptable
toxicity, death, or discontinuation from the study for any other reason, such as patient
refusal, withdrawn consent, lost to follow-up or investigator decision.