Pentostatin, Alemtuzumab, and Rituximab in Treating Patients With Relapsed or Refractory Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma

DISEASE CHARACTERISTICS:

Histologically or cytologically confirmed chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) meeting the following criteria:

Minimum threshold peripheral blood lymphocyte count of 5 x 10^9/L (CLL variant) OR adenopathy > 1 cm or palpable splenomegaly (SLL variant)

Immunophenotypic demonstrations of a population of B lymphocytes (as defined by CD19+) that are monoclonal (by light chain exclusion) AND have ≥ 3 of the following characteristics:

CD5+
CD23+
Dim surface light chain expression
Dim surface CD20 expression
FISH analysis is negative for IGH/CCND1 and/or immunostaining is negative for cyclin D1 expression

Must have progressive disease as indicated by any of the following characteristics (based on standard criteria for treatment):

Symptomatic CLL characterized by any of the following:

Weight loss > 10% within the past 6 months
Extreme fatigue
Fevers > 38.5° C (not due to infection)
Drenching night sweats without evidence of infection
Evidence of progressive bone marrow failure with hemoglobin < 11 g/dL or platelet count < 100 x 10^9/L
Massive and progressive splenomegaly (> 6 cm below left costal margin)
Massive (> 10 cm) or rapidly progressive lymphadenopathy

PATIENT CHARACTERISTICS:

ECOG performance status 0-3
Creatinine ≤ 2 times upper limit of normal (ULN)
Total bilirubin ≤ 3.0 times ULN OR direct bilirubin ≤ 1.5 times ULN
AST ≤ 3.0 times ULN (unless due to hemolysis or CLL)
Willing to provide mandatory blood samples for research studies
Not pregnant or nursing
Negative pregnancy test
Fertile patients must use effective contraception during and for up to 12 months after completion of study treatment
No other active primary malignancy that requires treatment or limits survival to ≤ 2 years
No active autoimmune hemolytic anemia, immune thrombocytopenia, or pure red blood cell aplasia
No New York Heart Association class III or IV heart disease
No myocardial infarction within the past month
No uncontrolled infection
No HIV infection or AIDS
No active hepatitis B infection (i.e., HBsAg or HBeAg positivity) or hepatitis C infection by serology
No other comorbid condition

PRIOR CONCURRENT THERAPY:

No more than 3 prior treatment regimens for CLL that included purine analogue drugs (e.g., fludarabine, pentostatin, or cladribine) OR previously untreated CLL in patients with high-risk disease due to 17p13 deletion on FISH analysis
More than 4 weeks since prior major surgery
More than 2 months since prior alemtuzumab
Prior corticosteroids allowed
No concurrent continuous systemic corticosteroids