The purpose of this study is to evaluate whether patients with previously untreated, early stage CLL respond to empirical broad spectrum antibiotics and therefore test the hypothesis that occult bacterial infections are involved in the induction and maintenance of CLL.

Inclusion Criteria:

• Age > 18
• ECOG performance status of 2 or less.
• CLL with a diagnostic score of 4 or 5.
• Clinical stage A disease.
• No disease progression over a minimum of 1 month prior to commencement of therapy.
• Less than 2 adverse prognostic factors.
• Absence of adverse cytogenetics.
• Expected survival > 6 months.
• Able to give informed consent.
• No clinical evidence of active infection at the time of study entry.
• No known allergy to any of the study medications.
• Renal and liver function tests within normal limits.

Exclusion Criteria:

• Disease progression during screening period.
• Known positivity for HIV types 1 or 2.
• Active infection at the time of screening.
• Pregnancy or lactation.
• Females of childbearing potential† and males not willing to practice an effective method of contraception whilst receiving the antibiotic regimen and for 4 weeks after the last dose.
• Concomitant medication likely to produce serious interaction with study drugs including warfarin type oral anticoagulants and anti-epileptics.