This trial consists of both a phase I portion and a phase II portion. In phase I, the MTD of lenalidomide is determined, starting with 5 mg/day given up to maximally 25 mg/day. In combination with this treatment, bendamustine and rituximab are given at fixed doses.~The phase I portion follows a sequential dose escalation, 3+3 design. Initially, three subjects are started treatment with dose regimen 1 (5 mg/day). After the third subject completed two cycles of treatment, if no DLT has occured, the next group of three subjects are treated at the next dose level of lenalidomide (10 mg/day). If one of the three initial subjects experiences a DLT, the cohort is expanded to six subjects. If less than two out of the six subjects experiences a DLT, then the next higher dose group is initiated. If two or more subjects experiences a DLT, no higher dose levels will be tested and the MTD dose has been exceeded.~Additional subjects are enrolled at the MTD on the phase II portion of the trial.~The above described treatment with lenalidomide, bendamustine and rituximab are given in 6 cycles, cycle length 22 days. Lenalidomide is given day 1-21, bendamustine day 1-2 and rituximab day 1. During the following maintenance treatment, single treatment with lenalidomide will be given with the same dose of lenalidomide (25 mg/day) for 7 cycles, whether in phase I or phase II portion of the trial.
In phase I: Establishing maximally tolerated dose of lenalidomide in combination with bendamustine and rituximab.~In phase II: Evaluation of progression free survival with treatment with lenalidomide, bendamustine and rituximab