A Paradigm Shift in HIV Therapy: Evaluating CRISPR-Cas9’s Safety and Efficacy in SIV Eradication from Non-Human Primates

The battle against HIV has been a prolonged and arduous one, with significant strides in treatment but no definitive cure. In a groundbreaking study, researchers have shifted the paradigm by using CRISPR-Cas9 gene editing technology to target and excise simian immunodeficiency virus (SIV), a close relative of HIV, from infected non-human primates (NHPs).  CRISPR-Cas9 is a revolutionary gene editing technology that has transformed the field of genetics. It stands for “Clustered Regularly Interspaced Short Palindromic Repeats” and “CRISPR-associated protein 9.” This system, derived from a natural defense mechanism found in bacteria, allows for precise editing of DNA at specific locations in the genome. In a new study published in Gene Therapy by Dr. Jennifer Gordon from the Excision BioTherapeutics, Inc and Professor Kamel Khalili from Temple University investigated a new CRISPR-Cas9 HIV treatment.

The study involved twelve male Indian rhesus macaques, infected with SIV and treated with antiretroviral therapy (ART). They were divided into groups, with varying doses of EBT-001, an AAV9-based vector delivering SaCas9 and dual guide RNAs designed to target the SIV genome. The macaques received a single intravenous infusion of EBT-001. Researchers monitored the animals for weight, lymphocyte and monocyte counts, blood chemistries, cytokine levels, and off-target effects using whole genome sequencing. The biodistribution of the vector DNA in tissues and blood was quantified using a TaqMan-based qPCR assay.

The authors found that EBT-001 was well-tolerated across all dosage groups, with no significant off-target effects or abnormal pathology. This establishes the safety profile of CRISPR-Cas9 in a large animal model, a critical step towards human application. Moreover, the vector DNA was broadly distributed across known tissue reservoirs of SIV, including the spleen, lymph nodes, and colon. This widespread distribution is crucial for targeting the virus in all potential reservoirs. According to the authors, there was successful editing of proviral DNA fragments in blood cells and various organs. The presence of excision products confirmed the effectiveness of CRISPR-Cas9 in excising viral DNA, a promising result for its potential in eradicating HIV. The authors demonstrated that animals treated with EBT-001 showed improvement in absolute lymphocyte counts and maintained normal body weight, suggesting an overall beneficial effect on health. Whole genome sequencing revealed no significant unintended editing events, reinforcing the specificity of CRISPR-Cas9.  Given the similarities between SIV and HIV, these results are a beacon of hope. They demonstrate the potential of CRISPR-based gene editing as a therapeutic approach for HIV in humans.

This research marks a pivotal moment in HIV cure strategies. The use of CRISPR-Cas9 to successfully edit SIV DNA in a large animal model not only demonstrates the feasibility of this approach but also paves the way for human clinical trials. The findings bring us a step closer to a potential cure for HIV, which could transform millions of lives globally. The journey towards an HIV cure has been laden with challenges, but this study illuminates a new path. The safety, efficacy, and precision of CRISPR-Cas9 in excising SIV from non-human primates herald a new era in HIV treatment. While further research is needed, particularly in human trials, the promise shown in this study is undeniably a leap forward in the quest to conquer HIV.