Phase II Protocol for CLL With Fludarabine and Cyclophosphamide With Rituximab (FCR) Plus Lenalidomide

Overview

In previously-untreated subjects with CLL, fludarabine and rituximab with or without cyclophosphamide (FR or FCR) produces complete responses (CR) of 40-80%. The major complication of FCR has been grade 3/4 neutropenia which was reduced using a lower dose of fludarabine and cyclophosphamide (FCR-Lite) The objective of this study is to evaluate the minimal residual disease (MRD) complete response rate (using the 2008 IWCLL guidelines) after 4 cycles of FCR-Lite plus lenalidomide in subjects with previously untreated CLL. Lenalidomide is active in frontline treatment of CLL as well as in patients with refractory disease. MRD has been demonstrated to be a sensitive surrogate marker for progression-free survival. If patients are MRD negative complete responders (CR) they will stop at 4 cycles of FCR-Lite followed by the lenalidomide consolidation/maintenance arm of the study. If they have a MRD positive CR or partial response (PR) they will continue with 2 additional cycles of FCR-Lite plus lenalidomide followed by lenalidomide consolidation/maintenance. They will be re-tested for MRD after the 6th cycle of FCR-Lite and after 6 and 12 months of lenalidomide monotherapy If they have no response (NR) or progressive disease (PD) following 4 cycles of FCR-Lite plus lenalidomide they will be removed from the study.

STUDY OBJECTIVES: Primary: The primary objective is to evaluate the complete response rate following 4 cycles of FCR-Lite plus lenalidomide in previously untreated patients with CLL. Secondary: The first secondary objective is to evaluate the toxicity of patients with previously untreated CLL treated with FCR-Lite plus lenalidomide, followed by lenalidomide. The second is to evaluate the overall response rate and overall survival of patients with previously untreated CLL treated with FCR-Lite plus lenalidomide followed by lenalidomide. The third is to determine whether adding lenalidomide as a consolidation/maintenance therapy will eliminate bone marrow minimal residual disease in CR patients and whether patients who have a PR after 6 cycles of FCR-Lite plus lenalidomide will respond to 12 months of lenalidomide. The final secondary objective is to determine whether the expression of ZAP-70, CD38, and chromosomes correlate with response rate, duration of response, and survival for previously untreated patients with CLL. STUDY DESIGN: 2-stage phase 2 study-design. 19 subjects are treated in stage-1 with FCR-Lite plus 5mg lenalidomide increasing to 10mg and 15mg in subsequent cycles depending on toxicity. If there are at least 5 CRs the study will accrue an additional 35 subjects (see statistical section). A secondary objective of this study will be to determine if MRD positive patients will become MRD negative with lenalidomide consolidation/maintenance and whether PR patients will convert to CRs Lenalidomide will begin 2 months after the last dose of FCR-Lite in all subjects with CR. It may begin as soon as 1 month after FCR-Lite plus lenalidomide in subjects with PR. Lenalidomide is given in 28 d cycles increasing the dose from 5 mg/d to 10 mg/d in cycle 2 and to 15mg in cycles 3-6 if well- tolerated (no grade-3 or -4 toxicity). Patients with creatinine clearance ≥30ml/min and \<60ml/min will start at 2.5mg daily increasing to 5 and 10mg in subsequent cycles . Reduction to the prior dose is allowed for grade-3/-4 toxicity. MRD will be studied by flow cytometry from bone marrow and peripheral blood samples following 4 and 6 cycles of FCR-Lite and after 6 and 12 months of lenalidomide in CR patients.