HIV drug reduces virus, boosts immunity in hard-to-treat patients

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A new HIV drug reduces viral replication and increases immune cells in people with advanced, drug-resistant HIV infection, according to a new study. In combination with existing medications, the drug holds promise for patients who have run out of effective treatment options, researchers say.

For some people with HIV, existing drug therapies fail to suppress the virus, leading to drug resistance and worsening disease. While several HIV drugs target the virus effectively, there has not been a new class of HIV drugs approved to combat the disease in a decade.

In March 2018, the FDA approved ibalizumab, a drug that targets the primary receptor for HIV entry into immune cells known as CD4 T cells. This new mechanism of action prevents HIV from entering target cells.

Viral load

Multiple sites participated in the new study, enrolling patients with multi-drug-resistant HIV. Patients received a dose of ibalizumab intravenously, in addition to their failing regimen, for one week. After that period, they received ibalizumab in combination with optimized treatment regimens for six months.

“To see viral suppression in a significant percentage of these patients at six months is heartening”

After one week on ibalizumab, the majority of the 40 patients (83 percent) enrolled in the study experienced decrease in viral load, which refers to the amount of HIV detected in the blood.

After 25 weeks, nearly half of patients saw viral load suppression dip below the level of detection. The researchers also saw an increase in CD4 T cells, which are a marker for immune strength. A single individual experienced an adverse event, which was felt to be ibalizumab-related and resulted in withdrawal from the study, the researchers say.

Remain vigilant

The results, which appear in the New England Journal of Medicine, are notable for this drug-resistant population of patients studied, says Brinda Emu, assistant professor of medicine at Yale University.

“These patients had extremely advanced HIV and resistant virus with limited options,” she says. “To see viral suppression in a significant percentage of these patients at six months is heartening. The result represents a much-needed new mechanism of action for patients who have highly resistant HIV.”

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As the first monoclonal antibody approved to treat HIV, ibalizumab is a promising option for individuals who have tried several other drug therapies. “It should be considered for patients that have multi-drug resistance given the efficacy seen this study,” Emu notes.

Because of its novel mechanism, ibalizumab will not interact negatively with other medications, researchers say. It is also delivered intravenously every two weeks and lasts longer than current HIV drugs, which are taken daily by mouth.

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“It’s ushering in a whole class of medicine and a new mode of delivery for the treatment of HIV,” Emu says. “I look forward to discussions in the community about how such a therapy will fit into the current treatment paradigm for HIV infection.

“We must also keep in mind that ibalizumab was approved with a smaller number of patients treated than other medications due to the rarity of patients with multi-drug resistant HIV. As such, patients and providers must remain vigilant for side effects and adverse events.”

The FDA’s Orphan Products Clinical Trials Grants Program funded the work.

Source: Yale University