Therapeutic vaccine offers hope in Aids fight
A team headed by Barbara Ensoli at the Istituto Superiore di Sanità in Rome developed the “Tat vaccine” which is injected into patients when they are already infected, with HIV. A spinout company has been set up to commercialise the technology.
The trial in South Africa, where almost 7m are believed to be HIV-positive, involved 200 people receiving standard antiretroviral drugs; half were given the Tat vaccine and half a placebo injection. After a year blood tests showed much higher levels of infection-fighting immune cells in the vaccinated group. Results are published in the journal Retrovirology.
Tat is a protein that HIV produces when infecting human cells. It plays a key role in viral replication and in the progress of the disease by weakening the host’s immune system, said Dr Ensoli: “By designing a vaccine that included a small amount of the Tat protein, we were able to induce an immune response capable of improving the effect of HIV drugs.”
HIV drugs — known collectively as antiretroviral therapy or Art — have been a huge success, reducing the global death toll of Aids from 1.5m in 2010 to 1.1m in 2015, according to UNAids. An estimated 17m people currently receive Art.
But the drugs are far from perfect. They do not affect hidden reservoirs of HIV lurking throughout the body; if the patient does not adhere strictly to the regime of pill-taking, the infection may flare up again; and the immune system often remains suppressed even when HIV levels in the blood are very low.
So a dozen or so therapeutic HIV vaccines are in clinical development. The Italian Tat vaccine is the most advanced of these — just three to four years from market — and its “manufacturing is straightforward and much less expensive when compared with other therapeutic HIV vaccines”, Dr Ensoli said. To make a significant impact on the Aids pandemic, new treatments must be affordable in developing countries where the disease is most prevalent, such as South Africa, she added.
To help pay for more extensive clinical trials of the Tat vaccine and commercialise the technology, Dr Ensoli — director of the National Aids Centre within ISS — has co-founded a private company called Vaxxit. She believes it is the first drug development spinout from ISS, which is Italy’s equivalent of the US National Institutes of Health or UK Medical Research Council.
“ISS has been a bit of a dinosaur in dealing with spinouts but that is changing now,” Dr Ensoli said. “We need spinouts to take discoveries from the lab out into the world.”
Giovanni Cozzone, Vaxxit chief executive, said the company “is actively engaged in raising at least €15m to be used in South Africa to conduct the final clinical studies for [regulatory approval]. Discussions are also taking place with key stakeholders in South Africa to establish a public-private partnership.”