To evaluate the complete clinical response rate according to the International Working Group criteria with a consolidation treatment with 90Y-ibritumomab tiuxetan (Zevalin®) in patients with high-risk follicular lymphoma with either partial or complete response to R-CHOP induction chemotherapy

Inclusion Criteria:

• Signature of the written informed consent by the subject or his/her legal representative before initiation of any trial specific procedure.

• Patients older than 18.

• Histologic diagnosis of CD20+, grade 1-3a follicular lymphoma as per the WHO classification.

• High-risk patients according to FLIPI before initiation of induction chemotherapy.

• Stage II-IV prior to initiation of induction treatment, or any stage in patients with grade 3 follicular lymphoma.

• Complete or partial response to the induction scheme.

• ECOG scale performance status 0 - 2.

• Life expectancy greater than 3 months.

• In women of childbearing age, use of a reliable contraceptive method.

• A suitable bone marrow reserve:

  • Lower than 25% Bone marrow infiltration by lymphoma.

  • Hb 10 g/dL. PMN leukocytes 1,500 cel/mm3, platelets 100,000/mm3

  • Suitable hepatic, renal and cardiac function:

    • creatinine <2,5 x UNL (upper normality limit).
    • bilirubin or ALT/AST < 2,5 x UNL

Exclusion Criteria:

• Patients with no objective clinical response to induction chemotherapy.
• > 25% bone marrow infiltration following induction chemotherapy.
• Platelets < 100,000 before radioimmunotherapy.
• Severe and/or uncontrolled concomitant disease:
• Hepatic, renal, cardiovascular, neurological or metabolic disease.
• Cardiac failure, ischemic cardiopathy, ischemic cardiopathy with a history of myocardial infarction or angor, or major ventricular arrhythmia.
• Positive regarding HBV, HCV, HIV.
• Active acute or chronic infection.
• Social, psychic or geographic disability to satisfy any of the treatment schemes.
• Pregnant and/or breastfeeding women, or adult patients of childbearing age who are not using a safe birth control device throughout the study treatment and at least 12 months thereafter.
• Known or suspected hypersensitivity, or confirmed or suspected adverse reaction to the study drugs and other related compounds (Rituximab, Ibritumomab tiuxetan, a history of sensitivity to murine proteins, dexametasone, cyclophosphamide and other anthracyclines, cytarabine).