Results were presented in two poster presentations at the Conference on Retroviruses and Opportunistic Infections (CROI) meeting in Boston.
The first poster, entitled Immune Function and Viral Load Post-AGS-004 Administration to Chronic HIV Subjects Undergoing STI, presents new findings from a Phase IIa clinical trial to assess safety and efficacy of AGS-004 during a 12-week antiretroviral therapy (ART) structured treatment interruption (STI) in chronic HIV-1 infected patients.
The goal of intervention was to induce long-term immunity against each patient’s unique viral variants and determine the impact on viral load control after stopping ART drug therapy.
Results showed that AGS-004 induced anti-HIV T memory stem cell-like immune responses (TSCM) that were associated with a longer time to viral rebound after ART treatment interruption. In addition, the longer time to viral rebound was also associated with lower expression of the checkpoint inhibitor PD-1 on activated CD8+ T cells.
Argos Therapeutics chief scientific officer research and development vice president Dr Charles Nicolette noted this is the first demonstration that AGS-004 can induce anti-viral TSCM-like immune responses in chronic HIV patients and that these responses are associated with viral load control in the absence of ART drugs.
"Establishing long-lasting immune memory is a critical component of durable viral load control and bodes well for our planned eradication and functional cure studies," Dr Nicolette added.
The second poster, entitled Immunogenicity of AGS-004 Dendritic Cell Therapy in Patients Treated During Acute HIV Infection, highlights results from an open-label, single arm study where treatment with AGS-004 was administered to patients who initiated ART within 45 days of primary HIV infection.
The study was led by Dr David Margolis, Dr Joseph Eron, Dr Nancie Archin, and Dr Cynthia Gay, faculty at the University of North Carolina School of Medicine, and Dr Charles B. Hicks, professor of medicine at Duke University Medical Center.
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 five months and another patient continues ART treatment interruption after nearly nine months. Additionally, 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.
The Argos AGS-004 clinical research program is supported by funding from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under Contract No. N01-AI-60019.