Inclusion Criteria:

- The diagnosis of CD20 positive chronic B lymphocytic leukemia (BCLL) confirmed by
biopsy or flow-cytometry.

- Previously treated patients with stage Rai I-IV and progressive disease (according to
IWCLL 2008 guidelines).

Active B-CLL is defined by at least one of the following:

At least one of the disease related symptoms:

- Constitutional symptoms:

- Weight loss >10% within the previous 6 months;

- Fatigue (e.g., WHO performance status >/=2);

- Fever >/=38C >/=2 weeks without evidence of infection;

- Night sweats for more than 1 month without evidence of infection.

- Evidence of progressive marrow failure as manifested by development of, or worsening
of, anemia and/or thrombocytopenia

- Autoimmune hemolysis and/or thrombocytopenia poorly responsive to corticosteroid
therapy.

- Massive (i.e., >/=6 cm bellow left costal margin) or progressive or symptomatic
splenomegaly.

- Massive lymphadenopathy or conglomerates (i.e., >/=10 cm in largest diameter) or
progressive or symptomatic lymphadenopathy.

- Progressive lymphocytosis with an increase >50% over a 2-month period or an
anticipated doubling time of less than 6 months. In patients with initial blood
lymphocyte counts of less than 30x10^9/L LDT should not be used as a single parameter
to define treatment indication. Marked hypogammaglobulinemia or the development of a
monoclonal protein in the absence of any of the above criteria for active disease is
not sufficient for protocol therapy.

- Either of the following:

- 18 years of age or older with impaired performance status (CIRS > 6) and /or

- 65 years of age or older with any performance status.

- Signed informed consent form.

Exclusion Criteria:

- Intolerance to exogenous protein or known severe reaction to the administration of
Rituximab.

- Active infection.

- Cancer radiotherapy, biological therapy or chemotherapy within 3 weeks prior to Study
Day 1.

- TBC or fungal infection within the past 6 months even if adequately controlled by
treatment.

- Severe organ deficiency preventing the participation in the study.

- Major surgery, other than diagnostic surgery, within 4 weeks prior to Study Day 1.

- Active peptic ulcer.

- Inadequately controlled diabetes mellitus.

- Suspected or confirmed B-CLL CNS disease.

- Known to be HIV positive.

- Difficult to control, uncooperative patients.

- Allergic disorders in need of chronic glucocorticoid therapy.

- Other oncological diseases requiring active treatment (except hormonal therapy).

- Pregnancy and breastfeeding.

- Patients of reproductive potential who are not using effective methods of
contraception.