Imaging results after CHOP-rituximab followed by 90Y ibritumomab tiuxetan and rituximab (R) in patients with previously-untreated follicular lymphoma (FL)

7589 Background: There has been some question regarding the predictive value of 111In scans in FL. We report imaging results with fusion PET-CT scans and 111In scans in a single-institution, non-randomized, phase II trial in patients with FL treated with CHOP-R followed by 90Y ibritumomab tiuxetan (Zevalin (Z)) and R. Methods: Eligible patients have CD20 positive FL, Grade 1–3 or transformed, Stage II-IV, no prior treatment with monoclonal antibody or chemotherapy, and symptomatic disease (if grade 1–2). CHOP-R is given every 21 days for 3 cycles. Four weeks after the last dose of CHOP-R, patients receive the Zevalin regimen, which includes 111In imaging and 90Y therapy. One week after Z, patients receive R 375 mg/m2 IV weekly for 4 doses. Bone marrow examination and fusion PET-CT scans are performed at baseline, after CHOP-R, and 12 weeks after Z. The primary endpoint is CR, and responses are reported using the International Working Group (IWG) criteria with the additional requirement of a negative PET s...