Inclusion Criteria:

• Patients with relapsed or refractory hematologic malignancy. The anticipated patient population are patients with chronic lymphocytic leukemia (CLL), non-Hodgkin's lymphoma or myeloma
• Patients with a history of a hematologic malignancy that has previously been shown by flow cytometry or immunophenotyping analysis to express CD52
• Any chemotherapy, major surgery or irradiation must have been completed at least four (4) weeks before enrollment in this study (6 weeks for mitomycin-C or nitrosourea)
• Patients have recovered from the acute side effects due to prior therapy
• Life expectancy of > 3 months
• World Health Organization (WHO) Performance Status 0-2
• 18 years of age or older
• Adequate organ function as defined in the protocol

Exclusion Criteria:

• Prior therapy with CAMPATH
• Use of an investigational agent within two (2) weeks prior to study enrollment
• History of anaphylaxis following exposure to humanized monoclonal antibodies
• Known human immunodeficiency virus (HIV) positive
• Prior autologous bone marrow or stem cell transplant if within six (6) months of study entry
• A history or prior allogenic bone marrow transplant or organ transplant
• Known, symptomatic central nervous system (CNS) involvement with lymphoma
• Pregnant or lactating women
• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection (excluding skin infection, lower urinary tract infection, or oral infection), symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements