abstract released today https://programme.aids202
Post# of 148110
https://programme.aids2024.org/Abstract/Abstr...actid=3857
excerpts
Title
Delivery and long-term expression of CCR5-blocking monoclonal antibody Leronlimab with AAV for ART-free remission from SHIV viremia
BACKGROUND: CCR5 blockade represents a scalable non-transplantation approach for long-term ART-free HIV remission. Here, we tested if AAV vectors could induce long-term expression of CCR5-blocking monoclonal antibody Leronlimab in a SHIV-infected rhesus macaques (RMs).
METHODS: Four SHIV-infected RMs received AAV9 encoding macaque Fc Leronlimab with stabilizing, silencing, and half-life extending mutations (AAV9-MacLSLeron). Animals were monitored longitudinally for CCR5 receptor occupancy (RO), plasma Leronlimab concentrations, antidrug antibodies (ADAs), and SHIV plasma viral loads.
RESULTS: All four AAV9-MacLSLeron-treated RMs reached 100% CCR5 RO on blood CD4+ T cells within 1 week and plasma Leronlimab was detected (>1ug/ml) within 2 weeks of AAV administration. In two of the RMs, SHIV viremia declined and reached undetectable levels between 10-40 weeks post-AAV, and those levels have remained undetectable through 70 weeks post-AAV. The remaining two RMs developed ADAs within 5-15 weeks post-AAV resulting in complete clearance of Leronlimab from plasma as well as a rapid decline in CCR5 RO. Spontaneous reemergence of CCR5 RO by Leronlimab was observed approximately 1 year post-AAV. One of the two animals has had full and sustained CCR5 RO, detectable plasma Leronlimab, and undetectable SHIV RNA in plasma for over 1 year post-reexpression. The second re-expressing animal has achieved and maintained 100% CCR5 RO for about 10 weeks, has detectable plasma Leronlimab, and has declined plasma viremia.
CONCLUSIONS: While further investigation is needed to develop AAV vectors and/or regimens that reduce the incidence of ADAs, the transgene reexpression phenomenon we have observed highlights the need to further investigate the interplay between AAV establishment and the development of ADAs. Overall, these data demonstrate the potential of AAV vectors for sustained antibody-based CCR5 blockade as a gene therapy approach for long-term ART-free HIV remission.