RATIONALE: Monoclonal antibodies such as alemtuzumab can locate cancer cells and either kill them or deliver cancer-killing substances to them without harming normal cells.

PURPOSE: This phase II trial is studying how well alemtuzumab works in treating patients with HTLV-1 associated adult T-cell leukemia/lymphoma.

OBJECTIVES:

• Determine the efficacy of alemtuzumab in patients with HTLV-1-associated adult T-cell leukemia/lymphoma.
• Determine the time course of alemtuzumab saturation in these patients.
• Determine the toxicity of this drug in these patients.

OUTLINE: This is a nonrandomized study.

Each patient receives escalating doses of alemtuzumab IV once daily until the target dose is reached and tolerated. Patients then receive the target dose of alemtuzumab IV over 2 hours 3 times weekly for a total of 12 weeks in the absence of disease progression or unacceptable toxicity.

Patients are followed monthly until the CD4 count has recovered and then every 3 months for 1 year, every 4 months for 1 year, every 6 months for 3 years, and then annually thereafter.

PROJECTED ACCRUAL: A total of 9-29 patients will be accrued for this study within 2.5 years.

DISEASE CHARACTERISTICS:

• Histologically confirmed adult T-cell leukemia (ATL)/lymphoma

  • More than 10% of malignant cells must express CD52 and CD25
  • All stages of tac-expressing ATL are eligible, including chronic or acute disease
  • No smoldering ATL

• HTLV-1-associated disease

  • Must have serum antibodies directed to HTLV-1

• Measurable disease

  • Greater than 10% abnormal (i.e., Tac homogenous strongly expressing) peripheral blood mononuclear cells considered to be measurable disease
• No symptomatic leukemic meningitis

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• Not specified

Life expectancy

• More than 2 months

Hematopoietic

• Granulocyte count at least 1,000/mm^3
• Platelet count at least 50,000/mm^3

Hepatic

• SGOT and SGPT no greater than 2.5 times upper limit of normal
• Bilirubin no greater than 3.0 mg/dL

Renal

• Creatinine less than 3.0 mg/dL

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 3 months after study participation
• HIV negative
• Other concurrent HTLV-1-associated diseases (e.g., tropical spastic paraparesis) are allowed

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No prior alemtuzumab
• No other concurrent monoclonal antibody therapy
• No concurrent gammaglobulins
• No concurrent biological response modifiers (e.g., interferon or similar agents)

Chemotherapy

• More than 3 weeks since prior cytotoxic chemotherapy for ATL
• No concurrent FDA-approved or investigational anticancer chemotherapy

Endocrine therapy

• Concurrent stable dose corticosteroids (administered for at least 3-4 weeks) allowed provided there is no evidence of tumor response

Radiotherapy

• Not specified

Surgery

• Not specified

Other

• No other concurrent investigational anticancer agents
• No concurrent zidovudine
• No concurrent drug that affects lymphocytes, except corticosteroids