Combination of Pentostatin, Bendamustine and Ofatumumab for Treatment of Chronic Lymphocytic Leukemia and Lymphoma

Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in the United States. There has been considerable progress in understanding the biology and treatment of CLL in the last 20 years. However, even with modern therapies, complete responses (CR) are achieved in approximately 25% of the patients with relapsed/refractory disease. Multiple studies have demonstrated that patients who achieve CR have better clinical outcomes than patients who do not achieve a CR with therapy. B-cell NHL is composed of multiple subtypes of neoplasm. These diseases are closely related to CLL in terms of natural history, biology, and responsiveness to similar therapeutic agents. These diseases are not usually cured by available chemotherapy and ultimately patients succumb to progression of resistant disease. Therefore, there is a need to develop better therapies to improve survival in patients with CLL and B-cell NHL.

Preclinical and clinical data suggests that pentostatin, bendamustine, ofatumumab are active drugs for the treatment of B-cell malignancies. In an earlier clinical trial conducted by Dr. Weiss (lead site PI), the combination of pentostatin and cyclophosphamide had very good activity in previously treated patients with B-cell neoplasms. This regimen was also better tolerated than similar fludarabine-based regimen. The response rates were improved with addition of rituximab, anti CD 20 antibody, to the above regimen. Studies have demonstrated synergy between bendamustine and purine analogs like pentostatin in killing cancer cell types of CLL and NHL. The combination of these three drugs (pentostatin, bendamustine and ofatumumab) has not been tested in clinical setting and we anticipate that the combination regimen will be more active than individual drugs alone. The aim of this trial is to find a safe dose of bendamustine to be used in combination with pentostatin and ofatumumab in patients with previously treated CLL and B-cell NHL.