MAGNIFY (NCT01996865) is a phase 3b, multicenter, open-label study of patients with grades 1-3b or transformed follicular lymphoma (FL), marginal zone lymphoma (MZL), or mantle cell lymphoma (MCL) who received ≥1 prior therapy and had stage I-IV, measurable disease. \~500 patients are planned for enrollment in 12 cycles of R2 induction, with a projected \~314 patients with ≥SD after induction randomized (1:1) to two maintenance arms. Induction includes oral lenalidomide 20 mg/day, days 1-21 per 28-day cycle (d1-21/28) plus IV rituximab 375 mg/m2, days 1, 8, 15, and 22 of cycle 1 and day 1 of cycles 3, 5, 7, 9, and 11 (28-day cycles). Patients are then randomized to maintenance lenalidomide 10 mg/day, d1-21/28, cycles 13-30, plus rituximab 375 mg/m2, day 1 of cycles 13, 15, 17, 19, 21, 23, 25, 27, and 29 (R2, Arm A), or rituximab alone (same schedule, Arm B). Patients receiving R2 maintenance after 18 cycles may continue maintenance lenalidomide monotherapy 10 mg/day, d1-21/28 (per patient and/or investigator discretion), until disease progression as tolerated. The primary endpoint is progression-free survival (per modified 1999 IWG criteria). Secondary endpoints include safety, overall survival, response rates, duration of response, and quality of life (exploratory). Patients will be followed for ≥5 years after the last patient initiated induction therapy. Enrollment in MAGNIFY began in March 2014; as of Jan 2016, 133 patients are enrolled.