The purpose of this research study is to assess the overall response rate of LBH589 in patients with relapsed or refractory Waldenstrom's Macroglobulinemia. LBH589 is a newly discovered compound that has killed Waldenstrom cells in laboratory studies, however, it is not known if LBH589 will show the same activity in people with Waldenstrom's Macroglobulinemia. This drug has been used in research for the treatment of other types of cancer, such as multiple myeloma.

This phase II study is designed to assess the toxicity profile and the proportion of overall response in patients with relapsed or refractory WM. This will study the effect of single agent LBH589 on response in these patients. Efficacy measures will include both objective clinical measurements and investigator-reported outcomes. Response and time to event analyses will follow the criteria set forth in the International Waldenstrom consortium recommendations. Prior to the start of the study, investigators will assess disease and perform a CT scan of the chest, abdomen and pelvis.

Response will be assessed after 2 cycles. If patients have stable disease or response, then they will continue on therapy until progression or unacceptable toxicity, being assessed every cycle until the sixth cycle and then every 3 months. Patients who show progression after 2 cycles will come off therapy and undergo event monitoring every 3 months. All responses will be assessed by M-protein quantification and immunofixation from serum and IgM monoclonal protein level. In addition, BM biopsies will be done at baseline, at the end of cycle 6 and at the end of all therapy. The protocol was amended because of concerns of toxicity to allow a starting dose of 25 mg; 12/36 (33%) patients were enrolled on the 25 mg dose.

Inclusion Criteria:

• Male or female patients aged 18 years or older
• Must have received prior therapy for their WM, any number of prior therapies is allowed
• Must have symptomatic relapsed or refractory WM
• Measurable monoclonal IgM protein in the blood and presence of lymphoplasmacytic cells in the bone marrow during any previous bone marrow
• Laboratory values as described in the protocol
• Clinically euthyroid
• ECOG Performance Status of 2 or less

Exclusion Criteria:

• Prior HDAC, DAC, HSP90 inhibitors or valproic acid for the treatment of cancer
• Patients who will need valproic acid for any medical condition during the study or within 5 days prior to first LBH589 treatment
• Peripheral neuropathy CTCAE grade 2 or higher
• Impaired cardiac function or clinically significant cardiac diseases
• Impairment of GI function or GI disease that may significantly alter the absorption of LBH589
• Diarrhea > CTCAE grade 1
• Other concurrent severe and/or uncontrolled medical conditions including abnormal laboratory values, that could cause unacceptable safety risks or compromise compliance with the protocol
• Patients using medications that have a relative risk of prolonging the QT interval or inducing torsade de pointes if treatment cannot be discontinued or switched to a different medication prior to starting study drug
• Patients who have received targeted agents within 2 weeks or within 5 half-lives of the agent and active metabolites (whichever is longer) and who have not recovered from side effects of those therapies
• Patients who have received chemotherapy or rituximab within 3 weeks or less; or radiation therapy to > 30% of marrow-bearing bone within 2 weeks or less prior to starting study treatment; or who have not yet recovered from side effects of such therapies
• Patients who have received corticosteroids 2 weeks or less prior to registration. Patients may be receiving chronic corticosteroids if they are being given for disorders other than than Waldenstrom's Macroglobulinemia
• Patients with active bleeding tendency or receiving any treatment with therapeutic doses of sodium warfarin or coumadin derivatives. Low doses of Coumadin to maintain line patency is allowed
• Patients who have undergone major surgery 4 weeks or less prior to starting study drug or who have not recovered from side effects of such therapy
• Women who are pregnant or breast feeding or women of childbearing potential not using an effective method of birth control
• Male patients whose sexual partners are women of childbearing potential not using effective methods of birth control
• Patients with prior malignancy within the last 5 years (except for basal or squamous cell carcinoma, or in situ cancer of the cervix)
• Patients with known positivity for human immunodeficiency virus (HIV) or hepatitis C; baseline testing for HIV and hepatitis C is not required
• Patients with a significant history of non-compliance to medical regimens or unwilling or unable to comply with the instructions given to him/her by the study staff

Assessed after 2nd cycle, every subsequent cycle for 6 cycles and then every 3 months. Once off-treatment, adverse events will be assessed for 30 days. The median (range) number of completed cycles of therapy was 5 (0- 32). Therefore, up to ~33 months.

Serious AEs (SAE) were defined as events with treatment-attribution of possibly, probably or definitely and grade 3 or higher. All remaining AEs are classified as Other AEs (OAE) including grade 3 or higher events with treatment-attribution of unlikely and unrelated plus all grade 1 and 2 events. Maximum grade toxicity by type was then calculated within SAE and OAE datasets. No further data is available to specify classification of other beyond the general term.