Inclusion Criteria

Inclusion criteria:

- Patients must have a diagnosis of active multiple myeloma.

- Phase I and Phase II part: Patients must have received at least 2 but not more than
4 prior line of therapy and their disease has progressed during or after last
therapy.

- Phase Ib part: Patients must have received no more than 2 prior lines of therapy
(excluding dexamethasone as single agent).

- ECOG Performance Status of ≤ 2.

- Patients must have acceptable neutrophil and platelet counts as well as adequate
kidney and liver function.

- Patients must have magnesium levels above lower limit of normal or correctable with
supplements.

- Patients must be willing and able to undergo bone marrow biopsy/aspirate.

- Able to sign informed consent.

Exclusion criteria:

- Prior treatment with any HSP90 or HDAC inhibitor for the treatment of multiple
myeloma.

- Patients with unresolved diarrhea ≥ CTCAE grade 2.

- Patients with acute or chronic liver disease.

- Patients using medications that have a relative risk of prolonging the QT interval.

- Clinically significant cardiac diseases.

- Patients with known disorders due to a deficiency in bilirubin glucuronidation (e.g.
Gilbert's syndrome).

- Pregnant or lactating women.

- Fertile women of childbearing potential (WCBP) not using adequate contraception.

- Male patients whose partners are WCBP, not using adequate contraception.

- Patients who unwilling or unable to comply with the protocol.

- Phase Ib part: Peripheral neuropathy ≥ CTCAE grade 1.

- Phase Ib part: Prior treatment with bortezomib.

Other protocol-defined inclusion/exclusion criteria may apply