A Phase Ib/II, Multi-center, Open-label Study to Evaluate the Efficacy of AUY922 in Combination With Trastuzumab in Patients With Locally Advanced or Metastatic HER2-positive Breast Cancer, That Has Progressed After or During at Least One Trastuzumab-containing Regimen

Inclusion Criteria:

- Female patients with confirmed HER-2 positive , non-operable locally advanced or
metastatic breast cancer

- All patients must have received at least 1 but no more than 2 prior anti HER2 based
regimens including at least 1 regimen containing Trastuzumab.

- All patients must have at least one measurable lesion as defined by RECIST criteria.

- All patients must have documented progressive disease following the last line of
therapy before entering the study

- ECOG Performance status ≤ 1

Exclusion Criteria:

- Patients with known CNS metastasis which are: symptomatic or require treatment for
symptom control and/or growing

- Prior treatment with any HSP90 or HDAC inhibitor

- Impaired cardiac function

- Acute or chronic liver or renal disease

- Patients who are currently receiving treatment with any medication which has a
relative risk of prolonging the QTc interval or inducing Torsades de Pointes and
cannot be switched or discontinued to an alternative drug prior to commencing AUY922

- Patients with a history of another primary malignancy that is currently clinically
significant or currently requires active intervention

- Patients who do not have either an archival tumor sample available or are unwilling
to have a fresh tumor sample collected at baseline.

Other protocol-defined inclusion/exclusion criteria may apply