Incidence of thromboses and secondary cancers in patients with multiple myeloma after lenalidomide-based induction followed by maintenance as first-line therapy: A systematic review and meta-analysis.

Abstract

e19510 Background: Lenalidomide, an immunomodulatory drug (IMiD) is one of the backbones of standard first-line induction regimen for multiple myeloma (MM). Lenalidomide maintenance is associated with improved progression-free survival, especially after bone marrow transplantation. The optimal duration of maintenance therapy is unknown. In our study, we evaluated the incidence of any thrombosis, venous thrombosis (VTh) and arterial thrombosis (ATh) as well as any secondary cancers, secondary solid and hematologic cancers in patients with MM who received lenalidomide-based first-line induction followed by lenalidomide maintenance for at least 6 months. Methods: This systematic review identified pertinent clinical trials from MEDLINE, Embase, and CENTRAL databases from inception to December 31, 2023. After two rounds of review by 4 authors independently, 25 clinical trials in patients with MM met the above eligibility criteria. The number of cases with any thrombosis, VTh, ATh, any secondary cancers, secondary solid and hematologic cancers along with the total number of patients in the arms with lenalidomide-based therapy were extracted from each trial. The incidence meta-analysis was performed using the “meta” package version 6.2-0 of R version 4.2.2 via a random-effects model. Pooled incidence and its associated 95% confidence interval (CI) were reported for each outcome. I² statistic was used to determine the heterogeneity of the studies. Results: 10743 patients were reviewed from 25 clinical trials. The pooled incidence rate of any thrombosis was 4% (0.04; 95% CI: 0.03 to 0.06, I2=91%). The pooled incidence rate of arterial thrombosis and venous thrombosis was 1% (0.01; 95% CI: 0.00 to 0.02, I2=77%) and 4% (0.04; 95% CI: 0.02-0.09, I2=94%) respectively. The pooled incidence rate of any secondary cancer was 5% (0.05; 95% CI, 0.04 to 0.07, I2=93%). The pooled incidence rate of secondary hematological malignancies was 2% (0.02; 95% CI, 0.01 to 0.03, I2=90%) and secondary solid cancers was 4% (0.04; 95% CI, 0.03 to 0.06, I2=76%). Conclusions: IMiDs are one of the backbones of the MM regimen. Our meta-analysis showed lenalidomide-based regimen increased the risk for thromboses – higher for VTh (4%) and slightly higher for ATh (1%). It also showed a higher rate of secondary cancers – both solid (4%) and hematologic cancers (2%). However, our study showed considerable heterogeneity. These events become clinically important as patients with MM live longer. MM patients on lenalidomide maintenance could benefit from an active surveillance, monitoring and early treatment program for these long-term adverse effects. VTh prophylaxis based on the type of regimen is already standard. Secondary cancer surveillance may need to be individualized for MM patients in remission.