Trial Shows Antibody Neutralizes, Reduces HIV Virus

T-cell infected by HIV (NIAID, Flickr)

26 Oct. 2022. Results from a clinical trial show an experimental one-time antibody therapy, even at low doses, lowers levels of HIV virus in people living with the disease. Researchers from ViiV Healthcare, based in London, presented the findings yesterday in the 30th HIV Glasgow Conference in Glasgow, Scotland. ViiV Healthcare is a joint venture of drug makers GSK, Pfizer, and Shionogi.

While research in the past 35 years has improved our understanding, diagnosis, and control of the human immunodeficiency virus, the disease remains highly contagious and continues to spread. According to World Health Organization, 38.4 million people worldwide are living with HIV, with 15 percent of people with the disease unaware they’re infected. Centers for Disease Control and Prevention say as of 2019, the latest year with complete data, 1.2 million people in the U.S. are living with HIV, with more than 30,600 new cases diagnosed in 2020. While the number of new cases are declining, about two-thirds of new cases (68 percent) are from male-to-male sexual contact.

While no cure is available for HIV infections, antiretroviral drugs are available to reduce HIV virus in the blood to negligible levels, which can also reduce the chance of spreading the virus to others. However, antiretroviral drugs must be taken regularly, with viral levels also monitored regularly. As reported by Science & Enterprise in January 2021, Food and Drug Administration approved an antiretroviral drug formulation taken monthly by people with the disease, made by ViiV Healthcare.

Virus unable to replicate

A drug in development by ViiV, code-named N6LS, seeks to offer a one-time treatment that reduces HIV levels in people with the disease. The company says N6LS is a synthetic antibody, given as a single infusion or injection, designed to block infection by different HIV strains in CD4+ T-cells in the immune system targeted by the virus. ViiV says N6LS binds to a specific site on the HIV surface called gp120 that prevents the virus from entering and infecting CD4+ T-cells. And, says the company, blocking the virus in this way makes it unable to replicate, which lowers the chance for further viral transmission.

The mid-stage clinical trial is enrolling 44 people with HIV in the U.S., Canada, Mexico, Argentina, and Brazil. ViiV reported findings from the first part of the study for identifying safe dosage levels, where 14 participants were randomly assigned to receive a low dose, or a 10 times higher dose infusion of N6LS. The study team then compared HIV levels in blood plasma samples after the infusions to samples taken before receiving N6LS, and watched for signs of adverse effects. The trial has no placebo group. Findings from the first part of the trial are expected to determine the N6LS dose in the second part of the study, where 30 more participants are tracked for 12 weeks.

ViiV says results show 13 of the 14 participants experienced lower median viral counts in their blood, across both dosage levels, but particularly among those receiving the higher dose. Nine participants reported adverse effects, of which six were linked to N6LS, but none of the adverse effects were rated as severe. All participants completed the first part of the trial.

The company says the findings prove the concept of a broadly neutralizing antibody or bNAb, and can meet a continuing need for new mechanisms to treat HIV infections. “Because of the rapidly changing nature of HIV and its potential to develop resistance to certain treatments,” says Kimberly Smith who heads R&D for ViiV Healthcare in a company statement, “the HIV community continues to be in need of medicines with unique mechanisms of action like bNAbs, which may open up a completely new approach to treating HIV.”

More from Science & Enterprise:

• Roche, Global Fund to Build Local Diagnostic Processes
• Clinical Trial Underway for One-Time Crispr HIV Treatment
• FDA Okays One-Time HIV Treatment Clinical Trial
• Gates Grant Funds HIV-Birth Control Implant
• Cancer Immunotherapy Adapted for HIV

Disclosure: The author owns shares in Pfizer.

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