The results of a small study published in The Lancet has generated talk of a possible cure for HIV infection but let’s not get ahead of ourselves.
It’s been a while since anyone in the HIV world has dared to use the ‘C’ word. While treatments have improved in leaps and bounds over recent years, the expectation remains that a cure for HIV is probably impossible to achieve, or is so far in the future that it belongs in the realm of science fiction.
Back in 1996, at the landmark Vancouver AIDS Conference, American researcher David Ho opined that the newly-discovered combination therapies could, if used over a period of years, eventually eradicate HIV from the body of an infected person. That claim proved wrong when it became clear that HIV lies dormant in viral reservoirs, ready to spring back into action as soon as treatment is withdrawn.
Since those days, we’ve become accustomed to hearing the words ‘chronic manageable illness’ repeated like a mantra — usually accompanied with a comparison between HIV and type-1 diabetes — both requiring ongoing medication to control, but both allowing people with these conditions to live ‘full and active lives’.
But with the reality of possibly decades of HIV treatments, with their attendant toxicities and side effects, starting to sink in, is it time to start dreaming of a cure again?
The Lancet article, published on 13 August, was certainly intriguing. The study looked at a drug widely used to treat epilepsy, valproic acid (Depakote). Test-tube studies had previously suggested that valproic acid could stimulate resting, HIV-infected CD4 cells to start expressing the proteins from the HIV genome — in layman’s terms, it might be able to coax HIV out of its hidey-holes.
Intrigued by the test-tube data, researchers at the University of Texas in the United States set up a small ‘proof of concept’ clinical trial to see whether there was evidence that the drug could have a similar effect when used in humans.
The researchers recruited four people whose long-term HIV infection was stable and well controlled on HAART. The four had been diagnosed between 1985 and 1995, and had maintained undetectable viral loads continuously for between two and six years.
They were all on different HAART combination at the start of the trial (two protease, two non-nuke), to which the researchers added twice-daily T-20 injections, in case the experiment triggered an increase in the amount of HIV in their blood.
After 4-6 weeks on their boosted HAART regimen, the participants added daily valproic acid tablets for the next three months, during which they had frequent tests to determine the number of HIV-infected cells in their bodies, including supersensitive viral load tests capable of measuring viral loads as low as one copy per millilitre.
After about 18 weeks, the researchers found that the number of infected cells had fallen substantially — by between 68 and 84 percent — in three of the four patients. The fourth patient had a smaller reduction of 29 percent. None of the patients experienced a spike in viral load.
Although this is a very small, brief trial at the cutting edge of HIV science, these results suggest that latently-infected CD4 cells may be able to reactivated safely and effectively, in at least some people — a finding that holds out the tantalising hope of eradication of HIV at some point in the future. In a commentary to the Lancet article, Canadian researcher Jean-Pierre Routy described the study as “the first glimpse of a new therapeutic approach that might represent a possible step towards making HIV-infection no longer a chronic disease.”
Routy’s language is sensibly cautious, and certainly stops short of using the ‘C’ word, but it’s clear that these results have medical researchers and positive people justifiably excited.
Of course, this was a very small pilot study, something which the researchers acknowledged in their report. “Our pilot study is limited and leaves many questions unanswered,” they wrote.
Routy echoed their concerns, wondering whether the results might be explained by an interaction between valproic acid and HAART, or whether even better results could be obtained by adding other agents such as IL-7 or a therapeutic vaccine into the mix. “These results, although preliminary, merit further urgent study,” he wrote. “In particular … a randomised trial to assess changes in the blood and tissue of the number of latently-infected cells.”
For people living with HIV, these results must of course be viewed with some caution — after all, we’ve been disappointed before. But while it’s probably a bit early to break open the champagne just yet, there is a promising message here. The day could yet come when the ‘C’ word makes a welcome return to our vocabulary.
Speed the day.
❧ The opinions expressed in this article are the author’s own.
