HIV, a therapeutic vaccine testing

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In Marseille, the first doses of a therapeutic vaccine against HIV were injected into patients as part of a clinical trial that will continue until June 2015. It would take several years for such a vaccine could be marketed, but this treatment option now seems accessible.

Pedro Lima on 18.04.2013

On 8 April, the Clinical Investigation Center Hospital of the Conception in Marseille, two patients infected with HIV have received the first dose of a therapeutic vaccine as part of a clinical trial to validate its effectiveness. Injections will continue at the rate of three new patients a week for a total of 48 volunteers, divided into four groups: three groups will receive three injections of the vaccine at different doses (11, 33 and 99 micrograms of active ingredient) the fourth will receive a placebo. Test objective, authorized on January 24 by the National Security Agency of the drug (MSNA): check that, three months after the end of treatment, the virus has been controlled in the body and does not resurface again beautiful, in the form of viral rebound. To confirm this beneficial effect, patients should stop their antiretroviral therapy, or HAART, two months after the injections.

The target: the Tat protein

Les atouts de Tat Oyi

Portrait of Tat Oyi

The specificity of this clinical trial of anti-HIV therapeutic vaccine, the only one currently in phase 2 in France (three others are being worldwide): it targets a protein, called Tat (for transactivating), which protects access , in people with HIV, cells infected with HIV and prevents the immune system from attacking them. To counteract this negative effect of the Tat protein, the vaccine developed over the past fifteen years, contains a synthetic protein, called Tat Oyi, which is a variant of the target protein. The goal is to enable, through Tat Oyi, the immune system against Tat, and thus enable it to neutralize Tat with antibodies. Interest would then be able to reduce the use of HAART, whose side effects are numerous. Or, if successful, can waive it.

If successful this first phase, a second phase will, by 2014, to demonstrate the effectiveness of the vaccine on a group of patients statistically significant, 80 patients divided into two groups. The first would be vaccinated with the optimal dose of Tat Oyi, the second using placebo. For now, thirty patients only on 2000 volunteered were identified as meeting the stringent criteria of the protocol under the leadership of Dr. Isabelle Ravaux. HIV-positive patients who are particularly accepting an informed manner to interrupt their HAART for two months at the end of three vaccinations to effectively measure the effect of the latter.

The advantages of Tat Oyi

If researchers and doctors are very cautious, the vaccine, the manufacture has been entrusted to the company Biosantech has several strengths. Studies on macaques have shown its ability to control the infection, and also seem to indicate that it could also have a preventive effect. Another advantage throughout basic research phase, the variant Tat Oyi has shown an amazing ability to recognize all shapes, varied, Tat protein. Much hope that will be confirmed or not by testing that begins in Marseille. First deliverables in a journal at best at the end of 2014.

Point Clinical Trials EVA TAT


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(October 15, 2013)

After getting the Clinic Trial Authorisation issued January 24, 2013 by the National Agency of Drug Safety, Biosantech SA was started Phase I clinical trial of its vaccine against AIDS from the Tat Oyi .The March 25, 2013, pre inclusion of the first patient took place, inclusion corresponding to the first injection took place on 10 April.

Three groups of patients were vaccinated with three different doses: 11 mcg, 33 mcg and 99 mcg of the active Tat Oyi. A fourth group (placebo) is vaccinated with the vaccine without the buffer active ingredient. Three vaccinations are performed one month apart (M0, M1 and M2) and are made of random double blind.

Biosantech SA obtained the passage of the clinical trial of its therapeutic vaccine in Phase II / a Sept. 2 with discontinuation of HAART in 1 patient for two months. The objective of Phase II / a is to determine what the most effective dose between 3 levels of vaccine.

Phase I is to date a total success because no side effects from vaccination were observed and that anti Tat immune response was observed in patients from the 2nd vaccination.

Knowing that observed after 3 weeks of triple therapy stop, there is a rebound viremia in 95% of patients. The aim is that at least 30% of patients
one of the three groups is able to maintain an undetectable viral load after 2 months of HAART stop. In order to begin Phase IIb, so you have at least four patients to one of three groups immunized with the active ingredient have been able to maintain an undetectable viral load for 2 months.

If there is an effective dose vaccination can be considered a success. This will be validated on a statically significant staff of 40 patients versus a placebo group. This is the objective of Phase II / b.

To know the results of the Phase II / a, we must do what is called « unblinding ». This unblinding in place when the last patient out of the study included in our protocol is one year (M12) after the first vaccination. One can expect a waiver of blind by the Supervisory Committee, the end of 2014.

Dr. Isabelle Ravaux (principal investigator), depending on availability of patients and capabilities of Clinical Investigation Center (CIC) did last inclusion mid November. Provision may be starting the pre-phase II b inclusions in July 2014. The last patient Phase IIb scheduled for late December 2014.

The laboratory used to analyze the secondary endpoints of clinical trials managed from November 2012 to May 2013 the synthesis of 5 variants of the Tat protein with biological activity. These Tat variants were aliquots and should be used with Tat Oyi antigen to test the antibody response to vaccination. Since the start of clinical trials, the laboratory has collected the CIC blood samples of patients in the trial EVA TAT, serum was extracted and sterilized according to a standardized procedure (SOP) developed in the laboratory before testing begins. . this SOP allowed serological studies in June 2013 on J-15 and M2 samples that confirmed some patients anti Tat-dependent response to vaccination, which has resulted in the passage authorization in phase II / has the clinical trial for the vaccine.

After being left with five candidate vaccines earlier this year, we are the only in the world to have had the authority to go into Phase II of our supervisory board thanks to the antibodies produced in response to vaccinations.

Corinne Muselier Treger.

President Corporate