Quantitative PCR Analysis for Bcl-2/IgH in a Phase III Study of Yttrium-90 Ibritumomab Tiuxetan As Consolidation of First Remission in Patients With Follicular Lymphoma

Purpose The randomized First-Line Indolent Trial (FIT) was conducted in patients with advanced follicular lymphoma (FL), to evaluate the safety and efficacy of yttrium-90 (90Y) ibritumomab tiuxetan given as consolidation of complete or partial remission. This study of minimal residual disease was undertaken in parallel, to determine the rate of conversion from bcl-2 polymerase chain reaction (PCR) –detectable to –undetectable status and the corresponding effect on progression-free survival (PFS). Patients and Methods Blood samples from 414 patients (90Y-ibritumomab, n = 208; control, n = 206) were evaluated using real-time quantitative polymerase chain reaction (RQ-PCR); 186 were found to have the bcl-2 rearrangement and were thus eligible for inclusion in the RQ-PCR analysis. Results Overall, 90% of treated patients converted from bcl-2 PCR–detectable to –undetectable disease status, compared with 36% in the control group. Treatment significantly prolonged median PFS in patients converting to bcl-2 PCR-u...