This is a prospective, multicenter phase II trial designed to evaluate the safety and activity of the combination of Bendamustine, Lenalidomide and Rituximab (R2-B) in patients with first relapsed/refractory mantle cell lymphoma (MCL) and the efficacy and safety of a maintenance treatment with Lenalidomide for 18 months from the end of R2-B (from month 7 to 24) for those responding to the induction.

This is a phase II study, non randomized, multicenter. Patients with MCL refractory to front line therapy or in first relapse will be enrolled.

The study includes an induction phase, a consolidation phase, a maintenance phase and a follow up phase.

Inclusion Criteria:

• Patient has a diagnosis of MCL according to the WHO classification;
• Patient age is ≥ 18 years;
• Patient has an Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 2;
• Understands and voluntarily signs an informed consent form;
• Able to adhere to the study visit schedule and other protocol requirements;
• Patients treated with one prior regimen and relapsed, or refractory to front line therapy; front line consolidation with autologous stem cell transplantation is considered to be part of first line therapy;
• Patient has at least one site of measurable nodal disease at baseline ≥ 2.0 cm in the longest transverse diameter as determined by CT scan (MRI is allowed only if CT scan can not be performed). Note: Patients with bone marrow involvement are eligible;
• Adequate haematological counts: ANC > 1.5 x 109/L and platelet count > 75 x 109/L unless due to bone marrow involvement by MCL;
• Conjugated bilirubin up to 2 x ULN unless due to liver involvement by MCL;
• Alkaline phosphatase and transaminases up to 2 x ULN unless due to liver involvement by MCL;
• Creatinine clearance ≥ 30 ml/min; a dose reduction of Lenalidomide for patients with creatinine clearance ≥ 30 mL/min but < 50 mL/min is planned;
• Written informed consent was obtained from the patient prior to any study-specific screening procedures;
• Patient has the ability to swallow capsules or tablets;
• Life expectancy ≥ 6 months;
• Disease free of prior malignancies (a part MCL) with the exception of currently treated basal cell, squamous cell carcinoma of the skin, or carcinoma "in situ" of the cervix or breast;

Exclusion Criteria:

• Patients who have received an experimental drug or used an experimental medical device within 4 weeks before the planned start of treatment. Concurrent participation in non-treatment studies is allowed, if it will not interfere with participation in this study;
• Patient has a history of CNS involvement with lymphoma;
• Patients with previous history of malignancies (a part MCL) ≤ 3 years before study accrual with the exception of currently treated basal cell and squamous cell carcinoma of the skin, or carcinoma "in situ" of the cervix;
• History of clinically relevant liver or renal insufficiency; significant cardiac, vascular, pulmonary, gastrointestinal, endocrine, neurologic, rheumatologic, hematologic, psychiatric, or metabolic disturbances;
• Patient has any other concurrent severe and/or uncontrolled medical condition(s) (e.g., uncontrolled diabetes mellitus, active or uncontrolled infection) that could cause unacceptable safety risks or compromise compliance with the protocol;
• Creatinine clearance < 30 ml/min;
• Patient has a known history of HIV seropositivity;
• Patient has active HBV hepatitis. The following categories of HBV positive patients but with non evidence of active hepatitis may be considered for the study and treated with R2-B (see also Section 8.1.8):
• patient is HBsAg + with HBV DNA < 2000 UI/ml (inactive carriers); HBV DNA > 2000 UI/ml is criteria of exclusion;
• patient is HBsAg - HBsAb +;
• patient is HBsAg - but HBcAb +
• Patients with HCV active hepatitis are excluded from the study. Patient with no evidence of active hepatitis and/or advanced chronic liver disease according to liver biopsy or fibro-scan evaluation may be included into the study
• Patients have received previous treatment with either Bendamustine and/or Lenalidomide.