The primary objective of this study is to determine the activity of OSI-461 given twice daily orally in previously untreated CLL patients. The secondary objective is to evaluate the safety profile of OSI-461 in this patient population.

Inclusion Criteria:

• Diagnosis of CLL established by bone marrow aspiration and biopsy or flow cytometry of peripheral blood.
• No previous therapy for CLL.
• Expected remaining life span greater than or equal to six months.
• 18 years or older.
• Willingness and ability to sign an informed consent.

Exclusion Criteria:

• Other active malignancy or history of treatment of any malignancy (excluding non-melanoma skin cancer) within the previous three years.
• History of other malignancy which could affect the diagnosis or assessment of OSI-461.
• Previous therapy for CLL.
• Use of an investigational medication or device within one month of initiating study therapy.
• Concurrent immunotherapy.
• Use of steroids at the time of enrollment (patients who require steroids after enrollment may remain on study).
• Any condition or any medication which may interfere with the conduct of the study.
• Serious uncontrolled intercurrent medical or psychiatric illness, including serious infection.
• Evidence of CNS involvement.
• Pregnant or nursing women.