Patient-Specific Immunotherapy Shows Promise in HIV Studies
Programmed dendritic cells attack disease antigens
New data from clinical studies of AG-S004 (Argos Therapeutics), a patient-specific immunotherapy currently in development for the treatment of human immunodeficiency virus (HIV) infection, were presented March 4 at the Conference on Retroviruses and Opportunistic Infections (CROI) meeting in Boston.
The first presentation discussed new findings from a phase IIa clinical trial that assessed the safety and efficacy of AGS-004 during a 12-week antiretroviral therapy (ART) structured treatment interruption (STI) in patients with chronic HIV-1infection. The goal of the intervention was to induce long-term immunity against each patient’s unique viral variants and to determine the effect on viral load control after stopping ART.
The results showed that AGS-004 induced anti-HIV T memory stem cell-like immune responses, which were associated with a longer time to viral rebound after ART interruption. In addition, the longer time to viral rebound was associated with lower expression of the checkpoint inhibitor PD-1 on activated CD8+ T cells.
The second presentation highlighted results from an open-label, single-arm study in which treatment with AGS-004 was administered to patients who initiated ART within 45 days after primary HIV infection.
The results showed that new anti-HIV memory T cell immune responses were induced in all six patients treated. One patient was able to maintain sufficient viral control while off ART drugs for approximately 5 months, and another patient continues ART treatment interruption after nearly 9 months. In addition, three of six patients had decreases in circulating CD4+ T cells containing HIV DNA of 25%, 47%, and 63%, respectively, when measured after three doses of AGS-004 while on ART.
AG-S004 was developed using the Arcelis immunotherapy technology platform. Arcelis captures mutated and variant antigens that are specific to each patient’s disease. It is designed to overcome immunosuppression by producing a durable memory T cell response without adjuvants, which may be associated with toxicity.
The Arcelis process uses only a small tumor or blood sample and the patient’s own dendritic cells, which are collected and optimized following a single leukapheresis procedure. The proprietary process uses RNA isolated from the patient’s disease sample to program dendritic cells to target disease antigens. The activated, antigen-loaded dendritic cells are then formulated into the patient's plasma and administered via intradermal injection.
Source: Argos Therapeutics Inc.; March 4, 2014.