Positive results from Argos Therapeutics' personalized immunotherapy candidate AGS-004 Phase 2a trial

Argos Therapeutics today announced two presentations at the AIDS Vaccine 2009 conference, detailing positive viral load, immune response and safety data from an ongoing Phase 2a trial of AGS-004, its personalized immunotherapy candidate. AGS-004 is a product of the Company’s Arcelis™ technology, and is a personalized, RNA-loaded, dendritic cell-based immunotherapy that is perfectly matched to each patient’s unique HIV viral burden. The presentations contained important results, including a favorable safety profile for AGS-004, the ability to induce partial to complete viral load control in the absence of antiretroviral therapy (ART) during a 12-week structured treatment interruption (STI), and a potent and diverse immune response to AGS-004 treatment. These AGS-004 results are unprecedented for an immunotherapeutic candidate in HIV and, if confirmed in an upcoming randomized study, could lead to a new treatment paradigm for HIV.

“The Arcelis approach to immunotherapy has broad potential as a new therapeutic strategy to combat HIV,” said Jean-Pierre Routy, M.D., from McGill University Health Centre in Montreal. “The level of viral load control in response to AGS-004 has been unexpectedly strong compared to what has been reported for other immunotherapies tested in similar patient populations. Additionally, because this approach uses patient-specific HIV antigens, it may overcome the extreme genetic heterogeneity of HIV from patient to patient, which has been one of the reasons for the failure of prior HIV immunotherapies.”

In an oral presentation, Dr. Routy, principal investigator of the ongoing Phase 2a trial, discussed data assessing the safety and impact of AGS-004 in controlling viral load during a 12-week STI from ART. Patients enrolled in the trial had pre-ART viral load levels ranging between 10,000-500,000 copies/mL. Data were presented for 16 patients that had successfully completed the STI. After the three month treatment break from ART, 13 of 16 patients had a lower viral load compared to their pre-ART levels, with a mean reduction of greater than 1 Log, corresponding to a greater than 80% reduction from pre-ART levels. AGS-004 also exhibited a favorable side-effect and safety profile, with no reports of autoimmunity or AIDS-defining events during the STI, and no treatment-related serious adverse events reported.

Charles Nicolette, Ph.D., Chief Scientific Officer and Vice President of Research and Development of Argos Therapeutics, commented, “These data demonstrate that AGS-004 may make a significant impact on pre-ART viral load levels during an STI, and that it is potentially able to keep patients safely off of ART for at least three months. Most of the patients in this trial were chronically infected, and did not have a genetic predisposition to viral control. Therefore, the large reduction in viral load from pre-ART is a very promising outcome. These data provide strong support for one of the main therapeutic objectives of AGS-004, that it could potentially offer patients partial or complete independence from ART, thereby addressing the side effects, resistance, and compliance issues associated with ART and improving patients’ quality of life.”

In a poster session, Bader Yassine-Diab, Ph.D., from the National Immunomonitoring Laboratory (NIML) at the University of Montreal Research Center, presented additional data supporting patients’ immune response to the autologous HIV antigens used in AGS-004 – Gag, Nef, Rev, and Vpr – following STI. Researchers analyzed patients’ anti-HIV-specific immune responses by evaluating the proliferation and the functionality of CD8+ and CD4+ T cells stimulated with these autologous HIV antigens. Preliminary results indicated an increase in HIV-specific CD8+ T-lymphocyte polyfunctional populations following immunotherapy with AGS-004, which was accentuated after the STI from ART.

“Although still preliminary, we are impressed with the diversity and strength of the immune responses observed so far. Importantly, the immune responses were composed of the same types of T cells observed in long-term non-progressors, which are individuals who are infected with HIV, but whose infection does not rapidly progress to AIDS,” said Rafick Sekaly, Ph.D., Scientific Director of the NIML.

Based on these positive data from the current Phase 2a study, Argos is planning on initiating a Phase 2b trial in the first half of 2010. The majority of the costs of this next trial will be funded by the National Institutes of Health, as part of a $21 million contract that Argos was awarded in 2006.

SOURCE Argos Therapeutics, Inc.