R-GEM-Lenalidomide versus R-GEM-P as second-line treatment of diffuse large B-cell lymphoma: results of the UK NRCI phase II randomised LEGEND trial.

Outcome of patients with relapsed/refractory (r/r) diffuse large B-cell lymphoma (DLBCL) remains poor, highlighting the need for novel treatment approaches. The multicentre randomised phase II LEGEND trial evaluated lenalidomide in combination with rituximab, methylprednisolone and gemcitabine (R-GEM-L) vs. standard R-GEM-P as second-line treatment of DLBCL. The study closed early to recruitment after the planned interim analysis failed to demonstrate a complete response (CR) rate of ≥ 40% in either arm. Among 34 evaluable patients, 7/18 (38.9%) achieved CR with R-GEM-L and 3/16 (18.8%) with R-GEM-P. Median event-free and overall survival was 3.5/3.8 months and 10.8/8.3 months for R-GEM-L and R-GEM-P, respectively. The incidence of grade ≥ 3 toxicities was 52% in R-GEM-L and 83% in R-GEM-P. Efficacy and tolerability of R-GEM-L seem comparable with R-GEM-P and other standard salvage therapies, but a stringent design led to early trial closure. Combination of lenalidomide with gemcitabine-based regimens should be further evaluated in r/r DLBCL.