Effect of Lenalidomide Maintenance in Chronic Lymphocytic Leukemia: A Meta-Analysis and Trial-Sequential Analysis

Chronic lymphocytic leukemia (CLL) is the most common lymphoproliferative disease in adults. Despite durable responses and sustained remission rates to frontline therapy, CLL is still incurable within standard therapy and eventually relapses. Maintenance therapies aim to achieve deep remission. However, the efficacy and safety of lenalidomide maintenance are still debated. Randomized controlled trials published before March 2022 were retrieved from databases. Primary outcomes were progression-free survival (PFS) and overall survival (OS). Trial sequential analysis examined analytical power in primary outcomes. Secondary outcomes were Grade 3-4 neutropenia, treatment discontinuation (TD), serious adverse events (SAE), and fatal adverse events (FAE). Hazard (HR) and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Four articles (733 patients) met the selection criteria. Lenalidomide maintenance was associated with a statistically significant effect in prolonging PFS (HR, 0.43; 95% CI, 0.28-0.68; I² = 57%) and higher proportion of SAE (OR 4.64; 95% CI 2.96-7.26; I² = 0%) and exhibited no difference in OS (HR, 0.62; 95% CI, 0.29-1.30; I² = 52%) observation/placebo. It showed no significant difference compared with observation/placebo regarding Grade 3-4 neutropenia (OR 2.30; 95% CI 0.84-6.28; I² = 81%), TD (OR 0.76; 95% CI 0.29-1.99; I² = 84%), and FAE (OR 0.86; 95% CI 0.28-2.63; I² = 0%). Lenalidomide maintenance can prolong PFS in CLL. Further studies should verify its effect on OS.