Inclusion Criteria

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