Long-term results with the Tat vaccine point to a new approach for a functional cure of HIV

By: Vaxxit
ROME - Feb. 16, 2019 - PRLog -- A new study announced by Istituto Superiore di Sanità (ISS, Rome, Italy) and published in "Frontiers in Immunology, February 13, 2019" suggests new avenues toward cure of HIV: the administration of the recombinant HIV-1 Tat protein (rTAT) to people living with HIV on antiretroviral therapy drastically reduced the "latent virus reservoir", which is invulnerable to HIV drugs. The rTAT has been developed at the National HIV/AIDS Research Center of the Istituto Superiore di Sanità (Rome, Italy), under the leadership of its Director, Dr Barbara Ensoli.

The results announced by ISS open new perspectives for a "functional" cure of HIV, i.e. the ability to control the virus during the suspension of antiretroviral drugs; a functional cure would ease the long-term clinical management of people with HIV by reducing the cumulative toxicity of antiretroviral drugs while improving adherence to therapy and quality of life that are crucial especially for children and adolescents.

Almost 40 years from the discovery of the virus, HIV/AIDS remains a global emergency, particularly for the poorest and most vulnerable populations in the world: women and children, homosexuals, bisexuals and transgenders (LGBT), sex workers, migrants, and users of injectable drugs. To date, almost 40 million people in the world live with HIV infection, half of them without any treatment, and international agencies are calling for a renewed effort, more investments and innovative strategies to find a cure for HIV and eradicate the virus.

Strict adherence to lifelong therapy is required to control HIV, in fact the virus hides in the "virus reservoir" as silent viral DNA invisible to the immune system and to antiretroviral therapy (ART), but it reactivates once therapy is interrupted. In the new study entitled "Continued decay of HIV proviral DNA upon vaccination with HIV-1 Tat of subjects on long-term ART: an 8-year follow-up study", published in the open access journal "Frontiers in Immunology", February 13, the authors present data of the long-term clinical monitoring of 92 volunteers who completed the previous phase II clinical trial in Italy (ISS T-002 ClinicalTrials.gov NCT00751595) and enrolled in the extended follow-up (ISS T-002 EF-UP, ClinicalTrials.gov NCT02118168). The 8-year study was conducted in 8 clinical sites in Italy: San Raffaele Hospital in Milan, L. Sacco Hospital of the University of Milan, San Gerardo Hospital in Monza, University Hospital of Ferrara, Policlinic Hospital of the University of Modena, Santa Maria Annunziata Hospital in Florence, San Gallicano Dermatological Institute in Rome, and the Policlinic Hospital in Bari. The results suggest new avenues towards a "functional cure" and, in perspective, the eradication of HIV.

The study shows that the volunteers treated with rTAT after being on ART for an average of 6 years, experienced, during the following 8 years, a continued decrease of viral DNA in blood, which occurred at an average speed 4-7 times greater than that observed in similar studies in patients treated with ART alone. Furthermore, in the vaccinated volunteers the reduction of the virus reservoir was associated with an increase in CD4+ T-cell number and CD4+/CD8+ T-cell ratio. A very small reservoir of latent virus (as evidenced by the low levels of proviral DNA in blood), and a good recovery of the immune system (as indicated by a high ratio of CD4+/CD8+ T lymphocytes) are found also in rare patients called "post-treatment controllers", who can control the reactivation of HIV after discontinuing therapy.

It is therefore conceivable that vaccination with Tat may confer to patients the ability to become post-treatment controllers, i.e. to control the virus without taking medications for periods of time the duration of which will be evaluated with specific clinical studies. Therefore, the results of the study lead to programmed and controlled therapy interruptions in volunteers treated with ART and rTAT that are currently being planned in order to verify this hypothesis.

The economic impact of a HIV cure is expected to be substantial. HIV is taking vast resources from the fight against poverty and inequality in the world: $ 563 billion between 2000 and 2015, a taxpayer contribution of $ 100 dollars in developing countries and $ 5,000 in Europe and North America ($ 330/$ year); and a net loss of national wealth (GDP) in African countries of between - $ 30 - $ 150 billion a year ($450 billion -4.5 trillion in 15 years), huge figures that impose urgent and innovative therapeutic solutions for HIV/AIDS.

For more information visit http://www.vaxxit.com

Giovanni Cozzone

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