A Therapeutic HIV Vaccine Is Not Yet At The Corner, Experts Say At An International Meeting

At the recent International Symposium on HIV and Emerging Infectious Diseases (ISHEID), new data on anti-HIV vaccines were presented by worldwide experts.

Online PR News – 07-June-2014 – There are two types of anti-HIV vaccines: the preventive ones and the therapeutic ones.

A preventive vaccine is designed to protect seronegative individuals, those who are not yet infected by HIV. A few years back, the “RV 144 trial” demonstrated a small advantage for the candidate vaccine versus the placebo but this superiority did not last for more than 6 months. Now, are tested other protective vaccines against HIV targeting the virus V3 loop by neutralizing antibodies or the stimulation of the CTL (Cytotoxic T Lymphocytes) response.

Regarding the search of a therapeutic vaccine, results are quite disappointing by now. A trial conducted By Professor Gatell in Madrid showed a limited effect on plasma viral load with a drop of just than 1 log.
Other groups are trying dendritic cells to boost the immune response, with more success, in particular in patients with undetectable viremia with antiretroviral therapy.

The final readout of these trials is to stop the antiretrovirals in order to see if the immune response induced by the virus is able to keep it at bay.

Therapeutic vaccines targeting a viral protein named Tat have been tried for 10 years now without success. However, the Marseille trial with anti-tat is not yet completed (consequently, no data were presented at the ISHEID) but fate will probably be a failure like others.

It is important for clinicians to not give false hope to the patients who are generally fed up of taking daily antiretrovirals. For now, the only proven way to stop disease evolution is to keep taking the antiretrovirals. This therapy also dramatically reduces the risk of sexual transmission of HIV and has the potential to decrease the pandemic.

The HIV therapeutic vaccine looks as a pipe dream because it has been well documented that the body immune response is unable to control HIV replication. HIV always remains hidden in the so-called “reservoirs” which contain tissues, organs and lymph nodes.

About the ISHEID: International Symposium on HIV and Emerging Infectious Diseases, Marseille, France. The meeting is held every other year and attracts more than 900 international scientists.