Phase II study of anti-CD4 idiotype vaccination in HIV positive volunteers.

A clinical phase II trial of postinfectional idiotype vaccination was performed in early stage HIV + volunteers. The mAb 13B8.2 is directed against the CDR3-homologous CD4/D1 region implicated in HIV-gp120 binding. We have previously shown that this mAb induces HIV-gp120 cross-reactive immunity. In addition, the mAb 13B8.2 was well tolerated in a clinical phase-Ia trial. In this phase-II trial, 158 patients with 350-500 CD4+ cells/microl blood were randomised to receive either 1.2 mg of alum-precipitated mAb 13B8.2 or placebo. The mAb was well tolerated evoking predominantly local side effects. Multivariant analysis of clinical study endpoints demonstrated a significant response in the verum group (intend-to-treat analysis). Titres of HIV-1 neutralisation in vitro were raised along with HIV/gp120 antigen binding titres. Our data indicate that patients treated with the idiotype vaccine will produce an augmented specific anti-viral immune response. The vaccine might thus have a positive impact on the course of HIV disease.