Current antiretroviral therapies are effective and provide an excellent quality of life for people suffering from HIV infection, but still doesn’t exist a vaccine that can control the infection.

For this reason, researchers from Viral Evolution and Transmission team, led by Dr. Gabriella Scarlatti, and from Infective Diseases Unit, headed by Professor Antonella Castagna – both from IRCCS San Raffaele Hospital, started a controlled randomized phase 1 clinical study focusing on people living with HIV in order to test the safety profile and immune response level in a new vaccine, HIVconsvX, which may be used for therapeutic goals.

HIV emergency

There are 85.6 million people in the world living with HIV and 160.000 of these are currently living in Italy, where in 2022 there were around 200 new diagnosed infections. “AIDS and HIV infections are still present. The research of new cures, such as vaccines, is an absolute priority of the international scientific community”, says Gabriella Scarlatti.

Nowadays, antiretroviral drugs can successfully block virus replication and make its presence in human blood not particularly significant; this makes life expectancy of a person living with HIV comparable to that of general people.

However, antiretroviral therapies – even in cases of “long acting” drugs that can be administered over long periods of time – must be pursued throughout entire life.

“Their interruption leads, in the majority of cases, to a viral rebound, i.e. a reappearance of viral load within 3-4 weeks” says Professor Castagna.

In addition to requiring a meticulous adherence for their efficacy, further problems lie in the possibility of side effects related to the long period of administration. Last but not least, in nowadays developing countries all of these therapies are hardly accessible.

The clinical study HIV-CORE007

HIB-CORE007 San Raffaele study plans to enroll 33 HIV-1 positive volunteers (≥18 years old and ≤60 years old) that have early started antiretroviral therapy with a stable regime for at least 3 months and have stably checked infection for at least 2 months.

In the first part, a phase 1 randomized study will be conducted, in single-blind, in order to evaluate safety profile of the new vaccine which is administered intramuscularly for the first time and for a second time after 4 months. 

The second part of the study aims at testing vaccine immunogenicity, i.e. the level of the immune response, and the capability to control virus. The study is therefore randomized in order to receive the vaccinal regime or placebo.

HIVconsvX is a mosaic vaccine created for a wide range of HIV-1 variants, potentially applicable to different HIV strains in any geographic region. Raffaele Dell'Acqua, Infectious disease specialist and principal investigator of the study says: "We hypothesize that this vaccination regime is able to enhance the immune response against relevant sequences of the HIV genome, so as to favor the control of replication."

HIV-CORE007 is the result of an international collaboration in which the immunogen has been developed by Tomas Hanke. The project is part of the European AIDS Vaccine Initiative 2020 (EAVI2020) and granted also by the Ministry of Health.

The challenge of the vaccine against HIV

Due to its great variability and mutability, HIV eradication is difficult to achieve but a therapeutic vaccine could promote long-lasting and effective control of the infection.

“Together with my research group, we believe that this and similar research can lead to relevant opportunities for long-term clinical management of people suffering from HIV, improving their well-being and their quality of life, also in populations that have no continuous access to drug.”, concludes Gabriella Scarlatti.