Six-month Rituximab-Lenalidomide regimen in advanced untreated Follicular Lymphoma: SAKK 35/10 Trial 10-year Update

The Swiss Group for Clinical Cancer Research (SAKK) and the Nordic Lymphoma Group conducted the SAKK 35/10 randomized phase 2 trial to compare rituximab (R) alone vs R plus lenalidomide (L) as initial treatment for follicular lymphoma (FL). Patients with grade 1 to 3A FL, requiring systemic therapy, were randomized to either R (n = 77; 375 mg/m2 IV × 1, weeks 1-4) or rituximab-lenalidomide (RL) (n = 77; R on the same schedule and L at 15 mg daily continuously). Responders (evaluated at 10 weeks) repeated R during weeks 12 to 15 with or without L (for a total of 18 weeks). Both arms had 47% of patients with a poor risk score on the FL International Prognostic Index. The primary end point, complete response (CR)/CR unconfirmed rates at 6 months, was superior with the combination, and after a median follow-up of 9.5 years, this has translated into a longer duration of response (median, not reached vs 3.2 years; hazard ratio [HR], 0.42; 95% confidence interval [CI], 0.21-0.86; P = .014), progression-free survival (9.3 vs 2.3 years; HR, 0.57; 95% CI: 0.37-0.89; P = .0128), and time to next treatment (median, not reached vs 2.1 years; HR, 0.43; 95% CI, 0.27-0.67; P < .001). Over 60% of RL responders remained in first CR at 10 years. Overall survival was similar in both arms (77% vs 78% at 10 years; P = .881). Toxicity was more common with RL but manageable. The SAKK 35/10 trial's long-term results confirmed a durable benefit of a short-term chemotherapy-free first-line RL regimen in symptomatic FL. This trial was registered at www.clinicaltrials.gov as #NCT0137605.