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New Antibody Treatment for Drug Resistant HIV Passes Crucial Test

An entirely new class of HIV medication called monoclonal antibodies can effectively treat multiple drug-resistant HIV, a recent study found.

For the first time in about a decade, scientists have identified a new way to treat HIV. The treatment, called ibalizumab, is a monoclonal antibody that binds to the body’s immune cells to prevent the virus from entering. Clinical trial results presented last week show that the long-acting drug causes few side effects and is capable of treating individuals who have become resistant to other classes of HIV medication.

“This is something to really pay attention to,” said Dr. Brinda Emu, an assistant professor of infectious disease medicine at Yale University School of Medicine. “It’s a very exciting development for infectious disease.”

Although previous classes of HIV drugs have done a tremendous job of viral suppression, many of them result in unwelcome side effects. Monoclonal antibodies, by contrast, are a more targeted approach that mimic the body’s own immune response to potential threats.

“It has a great potential,” Emu added, “to have a better side effects profile but also to avoid a lot of drug-drug interactions. As a person who studies immunology and biologics, it’s really exciting to see the infectious disease field really explore monoclonal antibodies for therapeutic options for our patients.”

Emu presented 48-week study results at IDWeek in San Diego as part of a larger panel on advances in modern antiretroviral therapy. The majority of the patients enrolled in the study were “highly resistant” to standard HIV medications, meaning that they had already exhausted 3 – 4 classes of HIV drugs in efforts to maintain viral suppression. Some patients carried strains of HIV that were resistant to all approved classes of antiretroviral therapy. In short, drug resistance made these patients extremely vulnerable to running out of options for HIV treatment.

The drug used in the study, ibalizumab, is not only the first monoclonal antibody but also the first long-acting and first intravenous drug for treating HIV. Theratechnologies Inc. is partnering on ibalizumab with TaiMed Biologics Inc. They have submitted study results to the U.S. Food and Drug Administration (FDA) and are currently awaiting further approvals. In a press release last week, company Chief Executive Officer, Luc Tanguay emphasized the need for a drug like ibalizumab.

"With the dramatic progress made over the past two decades in treating HIV, the crucial need for new treatments for these very vulnerable patients is often overlooked,” said Tanguay. “At Theratechnologies, focusing on these unmet needs is what we are committed to doing, and ibalizumab is a prime example of that.”

Individuals who harbor drug-resistant strains of the HIV virus are indeed one of the most vulnerable groups of persons with HIV. They represent less than 10% of patients in HIV care and tend to have had the virus for over 20 years. Drug resistance developed in these individuals for numerous reasons, mostly stemming from inadequate viral suppression. In the study, the average patient with drug resistance was over fifty years old and may have become infected with HIV at a time when potent antiretroviral drugs were unavailable. Others in the study were infected at birth and may have struggled to adhere to a strict drug regimen during their childhood and adolescence. These are just a couple ways in which drug resistance can develop.

This study reminds us of the constant need to develop new ways of suppressing the virus. The aspect of ibalizumab that is so exciting is the fact that it achieves viral suppression through an entirely different mechanism from other existing HIV medications. For people whose HIV has grown resistant to integrase inhibitors, reverse transcriptase inhibitors, etc., monoclonal antibodies represent a fresh and highly effective way of treatment. As the virus continues to mutate and adapt to existing treatments, new treatment mechanisms like this one will always be needed to maintain viral suppression.