A randomized phase II trial comparing chemoimmunotherapy with or without bevacizumab in previously untreated patients with chronic lymphocytic leukemia

Bevacizumab is a monoclonal antibody targeting vascular endothelial growth factor (VEGF) with in vitro pro-apoptotic and antiangiogenic effects on chronic lymphocytic leukemia (CLL) cells. As monotherapy in patients with CLL, it has no clinical activity. Here we report the results of an open-label, randomized phase II trial comparing the combination of pentostatin, cyclophosphamide and rituximab (PCR) either without or with bevacizumab (PCR-B) in previously untreated CLL patients. A total of 65 evaluable patients were enrolled, 32 receiving PCR and 33 PCR-B. A higher rate of grade 3-4 cardiovascular toxicity was observed with PCR-B (33% vs. 3%, p < 0.003). Patients treated with PCR-B had a trend for a higher complete remission (CR) rate (54.5% vs 31.3%; p = 0.08), longer progression-free survival (PFS)(p = 0.06) and treatment-free survival (TFS)(p = 0.09). No differences in PFS and TFS by IGHV mutational status were observed with the addition of bevacizumab. A significant post-treatment increase in VEGF levels was observed in the PCR-B arm (29.77 to 57.05 pg/mL); in the PCR-B arm, lower baseline CCL-3 levels were significantly associated with achievement of CR (p = 0.01). In conclusion, the addition of bevacizumab to chemoimmunotherapy in CLL is generally well-tolerated and appears to prolong PFS and TFS.