A Prospective, Multi Center Phase II Study Evaluating Predictive Factors for Lenalidomide Treatment in Relapse or Refractory Chronic Lymphocytic Leukemia Patients (LE.P.RE.): Preliminary Results about the First 20 Enrolled Patients

The aims of LE.P.RE. study include the identification of clinical and biological factors associated with clinical response and toxicity of lenalidomide monotherapy in relapsed/refractory CLL patients enrolled from 9 Italian centers. Lenalidomide treatment schedule starts with 5 mg daily and increases of 5 mg daily every two weeks, up to 25 mg daily or maximum tolerated dose. Therapy is scheduled to be administered for 12 courses (1 course = 4 weeks) unless disease progression or excessive toxicity are observed. Here we show preliminary results about the first 20 enrolled patients up to the 4th treatment course. Patients received a mean daily lenalidomide dose of 8 mg in the 1st course, 10 mg in the 2nd, 14 mg in the 3rd and 4th. Four patients left the study at the 1st course (1 acute renal failure ARF, 1 infection, 1 second neoplasia likely related to CLL, 1 consent withdrawal) and 3 patients at the 3rd (1 Tumor Flare Reaction TFR, 1 infection, 1 thrombocytopenia). The observed toxicities are listed in Table 1. After the 4th course, 13 patients were evaluable for response: 9 partial response (PR), 3 progressive disease (PD) and 1 stable disease (SD) [ORR 69%]. View this table: [in this window] [in a new window] Table 1 Hematological and extra hematological toxicities (n° tot cases=20) We compared the levels of several cytokines measured by ELISA in plasma of the 20 patients at baseline and day+8 of therapy. We observed a significant increase of IL2 Receptor (mean 55,31 vs 112,14 ng/ml; p<0,001), IL2 (14,15 vs 17,27 pg/ml; p=0,019), CCL3 (5,21 vs 21,23 pg/ml; p<0,001), CCL4 (24,76 vs 72,99 pg/ml; p=0,003), IL10 (2,65 vs 6,33 pg/ml; p=0,001), IL1b (0,94 vs 2,77 pg/ml; p=0,048), TNFa (35,00 vs 140,59 pg/ml; p<0,001) and IL8 (0,31 vs 3,50 pg/ml; p=0,037) and a decrease of Thrombospondin 1 (693 vs 488 ng/ml; p=0,037). Interestingly, we found that IL1b level decreased from baseline to day+8 in the 4 non responder (PD+SD) patients while increasing in the 9 responder (PR) patients. Moreover, we found that the 5 patients that experienced TFR or tumor lysis syndrome TLS had significantly higher CCL3 level at baseline than the other 15 patients (p=0,025). We also studied peripheral blood cell subsets (T, B, NK, monocyte, dendritic and endothelial cells) in the 20 patients by flow cytometry. From baseline to day+8 we observed a significant increase of the Thelper1/Thelper2 ratio (p<0,001), T cytotoxic1/Tcytotoxic2 ratio (p=0,001) and memory T cells % (p<0,001) as well as a decrease of naïve T cells % (p<0,001) and mean CD69 expression on T cells (p=0,016). Moreover, the expression of CD40 (p=0,001), CD80 (p=0,018), CD86 (p=0,003) and CD95 (p=0,008) were found to be increased on B-CLL cells. Finally, we observed a decrease of endothelial progenitors cells (EPC) (p=0,032) and live circulating endothelial cells (CEC) (p<0,001) and an increase of dead CEC (p