DISEASE CHARACTERISTICS:

• Biopsy-proven* aggressive B-cell non-Hodgkin's lymphoma (NHL), including 1 of the following histology subtypes:

  • Diffuse large cell NHL
  • Burkitt's or Burkitt-like NHL
  • Primary mediastinal NHL NOTE: *No needle aspirations or cytologies
• Relapsed or refractory disease
• Bidimensionally measurable disease
• Transformed NHL allowed
• Not eligible for stem cell transplantation (for patients registered to study at first relapse)
• No active CNS involvement by lymphoma

PATIENT CHARACTERISTICS:

• Zubrod performance status 0-2
• No history of allergic reactions attributed to compounds of similar chemical or biologic composition to PXD101
• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• WBC ≥ 3,000/mm^3
• Creatinine < 2 times upper limit of normal (ULN) OR creatinine clearance ≥ 60 mL/min
• No significant EKG abnormalities
• Bilirubin normal
• SGOT/SGPT < 2.5 times ULN (≤ 5 times ULN if liver involvement)
• No long QT syndrome or marked baseline prolongation of QT/QTc interval (e.g., repeated demonstration of QTc interval > 500 msec)

• No other significant cardiovascular disease, including any of the following:

  • Unstable angina pectoris
  • Uncontrolled hypertension
  • Congestive heart failure related to primary cardiac disease
  • Any condition requiring anti-arrhythmic therapy
  • Ischemic or severe valvular heart disease
  • Myocardial infarction within the past 6 months

• No clinical evidence of any of the following:

  • Severe peripheral vascular disease
  • Diabetic ulcers or venous stasis ulcers
  • History of deep venous or arterial thrombosis within the past 3 months
• No known AIDS or HIV-associated complex
• Not pregnant or nursing
• Fertile patients must use effective contraception
• No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer or in situ carcinoma of the cervix

PRIOR CONCURRENT THERAPY:

• At least 2 weeks since prior therapy and recovered

• No more than 5 prior chemotherapy regimens

  • Standard salvage chemotherapy followed by autologous stem cell transplantation is considered 1 regimen
  • Single-agent rituximab is not considered a chemotherapy regimen
  • Radioimmunotherapy is considered a chemotherapy regimen
• No major surgery within 28 days prior to study entry
• At least 2 weeks since prior valproic acid or any other histone deacetylase inhibitor
• At least 14 days since prior radiotherapy
• No concurrent medication that may cause Torsades de Pointes (i.e., prolongation of the QT interval > 500 msec)
• No concurrent combination antiretroviral therapy for HIV-positive patients