Discover the new weapons of science against HIV – Agência AIDS

Study treatments include injectable drug and messenger RNA immunizer

It was through the hands of French scientists Luc Montagnier (1932-2022) and Françoise Barré-Sinoussi, in 1983, that the world of science first glimpsed the HIV virus, which causes a severe disease that attacks the immune system. At that time, the Acquired Immunodeficiency Syndrome (AIDS), surrounded by prejudice, was even called by the unfortunate nickname of “gay cancer”. The terminology alluded to the first groups to be affected by the infection in the United States, still in 1981. It didn’t take long, however, for the virus to radiate to heterosexual men, women and even children, becoming a global public health problem.

Montagnier and Barré-Sinoussi’s discovery paved the way for scientists to look for tests to detect the virus and drugs that would offer the body some chance of defense. More than forty years have passed since the first cases, today medicine understands very well the action of HIV in the body.

Over these decades, it has developed around thirty antiretroviral drugs — for combined use — capable of inhibiting the replication of this infectious agent in the immune system, preventing it from pacifying the patient’s defenses and preventing it from leading to AIDS. Thus, the chain of dissemination of the virus, a fundamental step for the control of the epidemic, is broken.

The problem is that not everyone takes the pills in the required regularity and some people, due to treatment failures, fail to respond well to existing drugs. Aware of the limitations, the scientific community followed in search of advances. New drug presentations (single dose or injectables) are beginning to be scrutinized by regulatory agencies around the world. More than 20 immunizers in development stages are also in the sights of researchers, according to the International AIDS Vaccine Initiative (IAVI). One of them is tested in Brazil.

Prevention made easy

— It is a promising moment, of optimism. Researchers are advancing new classes of drugs, including innovations for people who have resistance after previous treatments have failed. The arrival of new drugs always opens up new hopes – says Valdez Madruga, coordinator of the HIV/AIDS Committee of the Brazilian Society of Infectious Diseases.

Among the celebrated recent innovations is the program to include a new injectable drug — the first of its kind — in the SUS. The study will be operationalized by the Oswaldo Cruz Foundation (Fiocruz), starting in the second half of this year, as it still needs to go through approvals, and will target populations at high risk of infection by the virus, in the case of young people, for example.

With a durable action, the drug removes the need for pills for daily use, which reduces the gap for treatment failures and, consequently, reduces the effectiveness of drugs. Its application lasts two months, so it only requires six injections over a whole year.

This presentation of the active ingredient cabotegravir is dedicated to PrEP – pre-exposure prophylaxis – whose function is to prevent HIV infection in healthy individuals who have risk behaviors. In Brazil, approximately 33,000 people use this oral drug care method today.

— It is a highly effective new strategy to prevent HIV infection. The person can use it only in the periods when they are more exposed to the virus. If that person, however, is constantly at increased risk of acquiring HIV, they will need to adhere to PrEp on an ongoing basis, and then the injectable becomes an even more attractive option,” says Beatriz Grinsztejn, head of the STD and AIDS Clinical Research Lab. from the National Institute of Infectious Diseases Evandro Chagas, from Fiocruz.

Two in one

Claudia Velasques, director and representative in Brazil of the Joint United Nations Program on HIV and AIDS (Unaids) also lists another important and recent advance: in 2021, the National Health Surveillance Agency (Anvisa) approved a drug that combines two active principles : dolutegravir with lamivudine. This, that is, for the treatment of people already identified with the virus.

– Although they are not new compounds, the combination of these two active ingredients in the same pill is unprecedented in the country and contributes to treatment adherence, since the person needs to take only one pill a day – he says.

Both innovations are under the umbrella of the pharmaceutical company GSK, which still wants the approval of injectable cabotegravir – in partnership with another drug from the pharmaceutical company Janssen – for the treatment of HIV in Brazil. The combination must still be endorsed by Anvisa to be used in the country.

— The easier and more comfortable the therapeutic regimen, the better the adherence. Studies show that the fewer pills and the fewer daily doses the treatment requires, the easier it is to continue,” says Rodrigo Zilli, Medical Director of HIV at GSK.

Vaccines under study

In another wing of development, two dozen vaccines dedicated to preventing infection are also making progress. The American pharmaceutical company Moderna, responsible for one of them, this year began phase 1 of development — the one dedicated to verifying the safety of a drug — of a vaccine that uses the messenger RNA platform, which is usually linked to high rates of efficacy, as has been reported. possible to observe with the new immunizers for Covid-19.

More advanced is the so-called “Mosaic study”, whose development includes Brazilian reference centers, such as the Instituto de Infectologia Emílio Ribas and Hospital das Clínicas, both in São Paulo. The study is in phase 3 and has already recruited all the necessary 3,600 volunteers. The vaccine uses technology similar to that used by the University of Oxford and AstraZeneca antigen against Covid-19.

— We already have results from the pre-clinical phase carried out in primates, which was 67% protection in unprotected exposures. It is something unprecedented in vaccines at this stage for HIV — says Bernardo Porto Maia, infectious disease specialist at Emílio Ribas and one of the leaders of the study.

The minimum forecast to assess effectiveness is for early 2023, he adds.

Path to healing

All these novelties represent a valuable advance for health in the country. Every day, around 90 Brazilians are diagnosed with the HIV virus, according to the average number of notifications sent to the Ministry of Health in recent years. Worldwide, there are 38 million people living with the virus. The persistent rates of transmission even make it necessary to repeat: the main means of transmission continue to be unprotected sex and the sharing of sharp items without proper hygiene.

Without large-scale replicable mechanisms to achieve a cure — some methods of bone marrow transplantation have shown positive results to eliminate the virus — strengthening prevention, treatment and immunization fronts are the main weapons in the arsenal against infection.

— The virus has an ability to be latent in some cells of the body, which are reservoirs of HIV. It’s as if he slept, without replicating, but still viable inside the cells. We still haven’t managed to achieve it, except by preventing its replication — explains Bernardo Porto Maia.

With the new strategies available, however, the fight against HIV points to the victory of science.

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