Inclusion Criteria:

- CLL confirmed by immunophenotyping and a relative preponderance of leukemic cells of
>70%

- ANC >1.500 /µl, Thrombocyte count >100.000 /µl und hemoglobin value >11 g/dl

- CLL patients with expression of immunoglobulin heavy chains (IGHV) 1-69 or 3-21

- Seropositive for CMV-specific IgG-antibodies

- Older than 18 years of age

- Written informed consent

- Able to comply with the protocol

- If female, should not be pregnant or be breast-feeding. Women of child-bearing age
must have a negative serum pregnancy test within 28days prior to enrollment into the
study, if a serum pregnancy test is not performed within 7 days prior first IMP
administration; a confirmatory urine test is required.

Exclusion Criteria:

- Indications for treatment of CLL (advanced stages of the disease)

- Having receiving chemotherapy for CLL within 3 months prior to enrollment

- Having received antiviral drugs or i.v. immunoglobulins within 3 months prior to
enrollment

- Significant thrombocytopenia (<100.000/µl) or anemia (Hb < 11 g/dl)

- Women of child bearing age not using effective contraception

- Pregnant of lactating female (as determined by a positive pregnancy test at screening
or within 7 days prior to first IMP administration)

- Known hypersensitivity to drug or its excipients