Idiotype vaccine therapy (BiovaxID) in follicular lymphoma in first complete remission: Phase III clinical trial results.

2 Background: In previous trials, tumor-specific purified idiotype (Id) protein conjugated to keyhole limpet hemocyanin (KLH) administered with granulocyte-monocyte colony-stimulating factor (GM-CSF) induced follicular lymphoma (FL)-specific immune responses and molecular remissions (Nat Med. 1999;5:1171-7). METHODS We conducted a prospective randomized double-blind placebo-controlled multicenter phase III study of patient-specific autologous tumor-derived Id vaccine in advanced stage previously untreated FL patients (pts) with a lymph node adequate for vaccine production (≥ 2cm). Pts achieving complete response (CR) or complete response unconfirmed (CRu) after chemotherapy (PACE: prednisone, doxorubicin, cyclophosphamide, etoposide) were stratified by International Prognostic Index risk group and randomized 2:1 to receive either vaccination with Id-KLH/GM-CSF or control (KLH/GM-CSF). The primary endpoint was disease free survival. RESULTS 234 pts were enrolled; 177 (76%) achieved CR/CRu and were randomized. Of 177 randomized pts, 117 maintained CR/CRu ≥ 6 mo per protocol requirement and then received at least one dose of vaccine, 55 relapsed before vaccination, 4 were vaccine manufacturing failures, and 1 violated protocol. Pts who received ≥ one vaccine dose constituted the modified intent-to-treat population for determination of efficacy. 76 pts received Id-KLH/GM-CSF and 41 pts received the control (KHL/GM-CSF). No serious adverse events were attributed to Id vaccination. At a median follow-up of 56.6 mo (range 12.6 -89.3 mo), median time to relapse after randomization for the Id-KLH/GM-CSF arm was 44.2 mo, versus 30.6 mo for the control arm (p = 0.045; HR = 1.6). CONCLUSIONS Id vaccination after a chemotherapy-induced remission of ≥ 6 mo prolongs remission duration in pts with FL. Compared to other phase III Id vaccine trials, the positive outcome of this study may reflect application of Id vaccine in pts in CR/CRu or use of hybridomas to produce Id. Genomic and immune response analyses are planned on residual autologous tumor and blood samples. Additional studies of this patient-specific vaccine in FL pts pretreated with anti-CD20 antibody-containing chemotherapy are indicated. [Table: see text].