Conference on Retroviruses and Opportunistic Infections (CROI)

Conference on Retroviruses and Opportunistic Infections (CROI)

Source:

Bailon L, et al. Abstract 161. Presented at: Conference on Retroviruses and Opportunistic Infections; March 6-10, 2021 (virtual meeting).

Disclosures: Kamarulzaman reports no relevant financial disclosures. Mothe reports being a coinventor of the HTI vaccine and a part-time clinical consultant for Aelix Therapeutics.
March 11, 2021
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HTI vaccines ‘induce some level of viral control’ in patents with HIV who are off ART

Source:

Bailon L, et al. Abstract 161. Presented at: Conference on Retroviruses and Opportunistic Infections; March 6-10, 2021 (virtual meeting).

Disclosures: Kamarulzaman reports no relevant financial disclosures. Mothe reports being a coinventor of the HTI vaccine and a part-time clinical consultant for Aelix Therapeutics.
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Vaccines containing a novel T cell immunogen were safe and highly immunogenic in early-treated people with HIV who discontinued ART, according to study results presented at the Conference on Retroviruses and Opportunistic Infections.

HTI vaccines — HTI stands for HIVACAT T cell immunogen (Aelix Therapeutics) — contain “a novel HIV vaccine immunogen designed at redirecting cellular immune responses to HIV targets associated with viral control,” researchers explained in an abstract.

The results presented at CROI represent “an exciting step forward to HIV cure research,” said International AIDS Society President Adeeba Kamarulzaman, MBBS, FRACP, FASc.

"The Aelix study has demonstrated that immunization with a mix of DNA and viral vector vaccines that contain a unique set of peptides called HTI is feasible and can induce some level of viral control in people with HIV who stop antivirals,” Kamarulzaman said in a statement. “This vaccine used peptides that are commonly recognized by elite controllers, people who can naturally control virus with no treatment.”

The HTI design “has demonstrated for the first time that it is possible to induce an immune response that can contribute to a better control of HIV,” Beatriz Mothe, MD, PhD, associate investigator at the IrsiCaixa AIDS Research Institute in Badalona, Spain, told Healio. “This is the first step toward a functional cure and positions HTI as a promising vaccine backbone in any combination cure strategy.”

Mothe and colleagues randomly assigned 45 early-treated patients with HIV to receive the DNA.HTI and MVA.HTI vaccines, followed by either the ChAdOx1.HTI and MVA.HTI vaccines or a placebo. They monitored viral load over 24 weeks and resumed ART if a patient’s viral load exceeded 100,000 copies/mL, exceeded 10,000 copies/mL over 8 weeks or CD4 counts dropped below 350.

A total of 30 participants received the ChAdOx.HTI and MVA.HTI vaccine and 15 received a placebo, and 41 of the 45 total participants completed the DNA.HTI and MVA.HTI or placebo regimen. The immunizations were found to be well tolerated, immunogenic — defined as a twofold or greater increase in HTI-specific T-cell responses — and caused no severe adverse events in 97% of vaccinated patients, the researchers reported.

Further, among participants without any potentially beneficial HLA class I alleles, 40% of vaccinees were able to remain off ART for 22 weeks compared with 8% of participants in the placebo arm.

"The level of viral control off ART was not as strong as what our long-term goal is in HIV cure studies, where we are aiming to achieve a viral load less than 200 copies/mL in the absence of ART,” Kamarulzaman said. “However, the beneficial effect of immunization on controlling viral load was clear and represents the first proof of concept in people living with HIV that stimulation of HIV-specific T-cells can contribute to cure strategies."

Mothe said one of the study’s limitations was the specificity of the population.

“This is a very specific population in which — in our setting — women are especially underrepresented,” Mothe said. “For future trials we plan to simplify the vaccination regimen in terms of number of vaccines used to make it more feasible, and to broaden the study population to get closer to the final target population of all people living with HIV.”