Last December Biovest International presented results of an 11-year, Phase II study it conducted with NCI testing its BiovaxID® in the treatment of mantle cell lymphoma (MCL). Study results showed that BiovaxID active immunotherapy following treatment with rituximab combination chemotherapy induced nearly universal immune responses. These responses, which strongly correlated with overall survival (OS) in treated patients, primarily consisted of tumor-specific T-cell immune responses.
BiovaxID comprises a protein isolated from each patient’s tumor combined with a carrier protein and administered with GMCSF. It stimulates the immune system to target a protein (idiotype) exclusively expressed on malignant B cells.
As part of the clinical development of BiovaxID, in 2000 the NCI began the Phase II trial in MCL patients who received rituximab-combination chemotherapy (etoposide, vincristine, doxorubicin, cyclophosphamide, prednisone, rituximab; EPOCH-R) prior to vaccination with BiovaxID to determine the impact of severe B-cell depletion on vaccine-induced immune responses.
With 122 months of median follow-up, the median overall patient survival in this study was 104 months. The investigators reported a significant association between T-cell immune responses (measured by antitumor, post-vaccine T-cell cytokine induction) and overall survival. The median overall survival in patients who did not develop or developed a below-median vaccine-induced T-cell response was 79 months at the time of follow-up.
“Our clinical trial experience with BiovaxID immunotherapy demonstrates that vaccination of lymphoma patients results in a broad spectrum antitumor immune response involving both cellular and humoral immune repertoires,” Carlos Santos, Ph.D., Biovest’s svp told GEN. “Further, randomized clinical trial data demonstrate that vaccination effectively extends remission duration lymphoma.
Dr. Santos emphasized that Biovest’s 11-year follow up with these vaccines “now shows that not only does vaccination provide clear improvements in remission duration but also that these vaccines may fundamentally alter tumor kinetics over many years. T-cell immune responses primed by Id vaccination in turn change tumor growth such that patients survive with lower disease aggressiveness.”
Moreover, he said, clinicians now for the first time may offer patients therapies that may truly add benefit without also adding significant risk, changing the risk/benefit equation in cancer treatment in ways even a decade ago would have seemed far beyond reach.