Efficacy of lenalidomide in relapsed/refractory chronic lymphocytic leukemia patient: a systematic review and meta-analysis

Therapeutic results of relapsed/refractory chronic lymphocytic leukemia (CLL) are very disappointing at present. Lenalidomide has been proved to be effective for relapsed/refractory CLL as a single agent or in combination with various chemo-immunotherapeutic regimens. However, current clinical experience in its usage is still limited. Because of existing considerable variability in different studies, a systematic review and meta-analysis was conducted to describe overall response rate (ORR) of lenalidomide in patients with relapsed/refractory CLL. Pooled estimate of cumulative prevalence of total ORR was 42.23 % (95 % confidence interval [CI], 32.49-52.61 %), while pooled ORR in regimen with lenalidomide plus anti-CD20 monoclonal antibody (mAbs) and lenalidomide mono-therapy were 60.01 % (95 % CI, 53.86-65.86 %) and 24.38 % (95 % CI, 16.15-35.06 %), respectively. There was no significant difference between L + R (lenalidomide plus rituximab) group and L + O (lenalidomide plus ofatumumab) group, with pooled ORR of 66.38 % (95 % CI, 57.96-73.87 %) and 57.40 % (95 % CI, 46.46-67.65 %), respectively. When co-administrated with anti-CD20 mAbs, dosage of lenalidomide was not the key factor of ORR in combination therapy. Pooled ORR of patient with high-risk cytogenetic in L + anti-CD20 mAbs group was 56.74 % (95 % CI, 45.53-67.30 %). In comparison with patients without high-risk cytogenetic receiving the same treatment regimen, no significant difference was observed, with relative risk (RR) of 0.87 (95 % CI 0.68-1.11). Our finding demonstrated that lenalidomide plus anti-CD20 mAbs could be an efficient therapy regimen for relapsed/refractory CLL patients, especially for those with high-risk cytogenetic factor.