A medical breakthrough for HIV: is a cure “reachable”?
An anonymous HIV patient in London has displayed “sustained remission” since halting antiretroviral treatment in September 2017. HIV attacks the immune system, leaving you vulnerable to “opportunistic infections”. If not treated correctly, HIV can evolve into a condition known as AIDS (Acquired-Immunodeficiency Syndrome).
About 12 years ago another man, Timothy Ray Brown, was deemed the first “successful” breakthrough towards an HIV cure. Brown suffered leukaemia and needed two bone marrow transplants. He nearly lost his life after a temporarily induced coma.
The London-based patient, however, had Hodgkin’s lymphoma. This patient received a bone-marrow transplant from a donor with a ‘CCR5 mutation’ in May 2016. During their respective treatments for leukaemia and Hodgkin’s lymphoma, both patients received immunosuppressive drugs.
The donors, known as Delta32, display a rare genetic mutation resistance to HIV, said to be from a North European gene pool. It prevents a protein called CCR5 from rising to the surface of white ‘T’ blood cells. This leaves nothing for the HIV virus cells to latch onto, preventing HIV from infecting cells altogether. What happens eventually is that the body seems to automatically keep the virus under control, without requiring support from ARVs.
Sustained remission, though, is not the same as being cured completely.
Although Brown’s viral load hasn’t ever reappeared as detectable, a number of important facts need to be considered. As of 2017, an estimated 36.9 million people were living with HIV, yet Brown is the only individual who remains free of the virus. Other people have been “cured” before and in every case (except for Brown’s) their viral load has relapsed within a few years.
While 18 consecutive ‘HIV-free’ months is remarkable, it’s still not sufficient proof that remission will last permanently. Any claim that an HIV patient is “functionally cured,” must be supported by ongoing and consecutive test results pointing to an undetectable viral load.
To some extent, this is accomplished today with ARVs. ARVs are HIV treatment medications which suppress the virus to such low levels that it’s no longer detectable in the bloodstream. This idea is been supported by government agencies like the U.S. Center for Disease Control and Prevention.
A functional cure occurs when HIV patients no longer require treatment to keep the virus suppressed. We are slowly heading in the right direction, thanks to multiple vaccines currently being studied and milestones in the pharmaceutical landscape. Scientists around the world hope that this will lead to long-acting HIV treatments (pills and vaccines) entering the market more frequently.
HIV can remain dormant in your body.
HIV researchers admit that functional cures will likely last no more than a decade at a time. Essentially, a functional cure means that the virus is still in your system, hiding in what is known as HIV reservoirs. Right now we have no way of predicting whether or not a relapse will occur once treatment stops. This applies even if in theory, it shouldn’t, like with the presence of the CCR5 mutation in white blood cells.
An eradication cure is an entirely different scenario. It would mean total eradication of the virus from the body: destroying every ounce of active (and dormant) HIV from the blood, organs, and reservoirs. We are not quite there just yet, but major advancements have been made. HIV patients now have almost equal life expectancy as their HIV negative peers, and that’s something worth celebrating.
So what does this mean in terms of an HIV cure?
It’s currently too early to know what the London-based patient’s ultimate contribution will be to the development of a cure. All medical teams can do is continue to closely monitor his viral load, and keep scientific communities informed. Bone-marrow transplants are unlikely to be a realistic or financially viable treatment option; powerful drugs already exist that help immensely with suppressing the viral load of HIV in patients. But rearming the body with immune cells similarly modified to resist H.I.V. might well succeed as a practical treatment, experts say.
“This will inspire people, that a cure is not [just] a dream,” said Dr Annemarie Wensing, a virologist at the University Medical Center Utrecht in the Netherlands. “It’s reachable.”
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King, M. 2015. Five things you don’t know about the first man cured of HIV. Queerty. 4 February. Available at: https://www.queerty.com/five-things-you-dont-know-about-the-first-man-cured-of-hiv-20150204 [Accessed 18 July 2019].
Mandavilli, A. 2019. H.I.V. is reported cured in a second patient, a milestone in the global AIDS epidemic. The New York Times. 4 March. Available at: https://www.nytimes.com/2019/03/04/health/aids-cure-london-patient.html [Accessed 18 July 2019].