DISEASE CHARACTERISTICS:

• Histologically confirmed diffuse large B-cell lymphoma

  • De novo or transformed* disease NOTE: *Patients with transformed diffuse large B-cell lymphoma must meet WHO criteria for diffuse large cell lymphoma on last biopsy prior to study entry AND have ≥ 1 prior histological diagnosis of follicular disease

• Relapsed disease, defined as recurrent or progressive disease after standard first-line chemotherapy (e.g., CHOP or an anthracycline-containing regimen equivalent) AND 1 systemic salvage therapy that may have included autologous stem cell transplantation

  • Patients who are not candidates for systemic salvage and/or stem cell transplantation are eligible
• Must have had a response that lasted ≥ 3 months OR stable disease that lasted ≥ 3 months after completion of the most recent treatment

• Failed no more than 3 prior treatment regimens

  • Pre-induction chemotherapy and autologous stem cell transplantation are considered 1 therapy
  • Antibody therapy (e.g., rituximab) given in combination with or as consolidation therapy after a chemotherapy regimen (without intervening relapse) is considered 1 therapy
  • Antibody therapy given as a single agent is considered 1 therapy
• Measurable disease, defined as 1 unidimensionally measurable lesion ≥ 2 cm by conventional CT scan OR ≥ 1 cm by spiral CT scan

• No active brain or leptomeningeal metastases, as indicated by positive cytology from lumbar puncture or CT scan or MRI

  • Previously treated CNS disease allowed provided there is negative cytology from lumbar puncture
• No known HIV-related malignancy

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2

Life expectancy

• Not specified

Hematopoietic

• Absolute neutrophil count ≥ 1,000/mm^3
• Platelet count ≥ 75,000/mm^3

Hepatic

• Bilirubin < 1.5 times upper limit of normal (ULN)
• AST and ALT ≤ 2.5 times ULN (5 times ULN if liver is involved by tumor)
• No active hepatitis B or C infection

Renal

• Not specified

Cardiovascular

• No symptomatic congestive heart failure
• No unstable angina pectoris
• No cardiac arrhythmia

Immunologic

• No acute infection requiring IV antibiotics or antiviral or antifungal agents within the past 2 weeks
• No ongoing or active infection
• No known HIV positivity
• No known allergy to any component of the study drug
• No acute or chronic graft-vs-host disease

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective double-barrier contraception during and for 14 days after completion of study treatment
• No other malignancy within the past 5 years except basal cell carcinoma or carcinoma in situ of the cervix
• No psychiatric illness or social situation that would preclude study compliance
• No other uncontrolled illness
• No circumstance that would preclude study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy

• See Disease Characteristics
• At least 4 weeks since prior biologic therapy
• No prior allogeneic stem cell transplantation
• No concurrent prophylactic growth factors
• No concurrent anticancer biologic therapy

Chemotherapy

• See Disease Characteristics
• At least 4 weeks since prior chemotherapy
• No concurrent anticancer chemotherapy

Endocrine therapy

• Concurrent systemic steroids allowed provided the dosage has been stabilized to the equivalent of ≤ 10 mg/day of prednisone for ≥ 4 weeks prior to study entry

Radiotherapy

• At least 4 weeks since prior radiotherapy
• No concurrent anticancer radiotherapy

Surgery

• At least 4 weeks since prior major surgery
• No prior gastrointestinal resection or procedure that may affect drug absorption

Other

• Recovered from prior therapy
• At least 4 weeks since prior investigational therapy
• No prior histone deacetylase inhibitors (e.g., FR901228, MS-275, or LAQ-824)
• No concurrent vitamins except a single daily multivitamin
• No other concurrent investigational anticancer therapy