The efficacy and safety of lenalidomide maintenance therapy after ASCT in patients with MM has been in question. In order to address the issue, we conducted a meta-analysis of two randomized double-blind placebo-controlled studies encompassing 1074 patients treated with lenalidomide or placebo maintenance therapy after ASCT. The predominant clinical outcomes of interest were overall survival (OS), progression-free survival (PFS), and adverse events. There was a marked benefit in PFS with lenalidomide (Odds Ratio [OR] = 2.5, 95% confidence interval [CI] = 1.93 to 3.24). There was statistically non-significant tendency toward benefit in OS with lenalidomide (OR = 1.21, 95% CI = 0.65 to 2.24). For adverse events, more patients in lenalidomide treatment arm experienced neutropenia (OR = 4.88, 95% CI = 3.67 to 6.50), infection (OR = 2.82, 95% CI = 1.67 to 4.73), hematologic cancers (OR = 3.31, 95% CI = 1.30 to 8.41), and solid tumors (OR = 2.24, 95% CI = 1.01 to 4.98). No significant differences were seen with deep vein thrombosis (OR = 2.15, 95% CI = 0.92 to 5.06), peripheral neuropathy (OR = 1.50, 95% CI = 0.53 to 4.25), thrombocytopenia (OR = 1.05, 95% CI = 0.12 to 9.54), and anemia (OR = 1.36, 95% CI = 0.02 to 83.86). Based on these results, we conclude that lenalidomide maintenance therapy for patients with MM after ASCT was effective in the improvement of PFS. However, treatment-related adverse events must be close monitored. Although there was a trend for increased OS with lenalidomide, there was no statistically significant difference in OS between lenalidomide maintenance therapy arm and placebo maintenance therapy arm. Therefore, longer follow-up and additional high quality RCTs were needed to evaluate the effects of lenalidomide maintenance on OS.
Keywords: Lenalidomide; maintenance therapy; meta-analysis; multiple myeloma.