A systematic literature review and meta-analysis of radioimmunotherapy consolidation for patients with untreated follicular lymphoma.

Background: Follicular lymphoma (FL) is characterized by multiple relapses and progressively shorter response durations with subsequent therapies. Despite the development of numerous treatment strategies to reduce the risk of progression, optimal therapeutic strategies for patients with FL remain undefined. Radioimmunotherapy (RIT) with an anti-CD20 antibody linked to iodine-131 or to yttrium-90 has emerged as well-tolerated treatment after induction. We conducted a systematic literature review and meta-analyses to quantify the benefits of consolidative RIT.

Methods: We searched the CENTRAL and MEDLINE libraries, and conference abstracts for reports on phase II/III clinical trials that assessed RIT consolidation for patients with untreated FL. Extracted data included pretreatment disease status, patient characteristics, treatment regimen, response rates, progression-free survival (PFS), and overall survival (OS). Pooled estimates of complete response (CR), overall response (OR), 2- and 5-year PFS and OS rates were computed by using random effects models.

Results: Eight studies (n = 783) were included in the meta-analyses. CR rates after RIT ranged from 69.0% to 96.5%, 2-year PFS ranged from 64.8% to 86.1%, and 5-year PFS ranged from 47.0% to 67.3%. The pooled estimates of the CR rate and OR rate were 82.7% (95% CI, 67.4%-91.7%) and 96.2% (95% CI, 90.4%-98.6%), respectively. The pooled estimates for 5-year PFS and OS were 57.6% (95% CI, 47.8%-66.9%) and 90.1% (95% CI, 83.9%-94.1%), respectively.

Conclusions: We believe that these aggregated data can further the discussion on RIT as a consolidation therapy and inform decisions on future study designs Additional studies are needed to compare the benefits of RIT consolidation to maintenance therapy with rituximab.