Until today, there are only two people and several mice known to have been cured of HIV. However, there is growing optimism that these breakthroughs will lead to a way of eradicating the virus without the need for further treatment.
“We now have very good understanding of why the virus keeps evading the antiretroviral therapy, and we know where it hides,” says Dr Peter Cherutich.
Dr Cherutich is a celebrated Kenyan public health specialist and HIV researcher, who became the first graduate of the PhD programme in global health metrics and evaluation at the University of Washington in 2015.
That year, the university awarded him the prestigious Gilbert S. Omenn Award, for his academic excellence and commitment to public health.
In 2016, a study he conducted in Kenya informed the World Health Organisation’s HIV self-testing and assisted partner notification guidelines.
Dr Cherutich took part in the exclusive Sunnylands Summit in February this year, where some of the world’s top researchers described how a future HIV cure might look like, its cost and delivery.
Dr Cherutich spoke to the Star on the ongoing global efforts to find a cure for HIV.
QUESTION: This year we’ve had two major breakthroughs in HIV treatment reported: The London patient who became the second person ever to be free of the virus after a bone marrow transplant, and, two weeks ago, researchers announced they cleared HIV from infected mice through gene editing. IS A CURE IN SIGHT?
ANSWER: There are two things that are related. One is it has always been the aspiration of the global community, of advocates and researchers, to find a cure. From day one, we knew that’s where the journey would end. The treatments are just intermediate, not the final solution. The treatments help a lot, but it’s been the aspiration to find a cure. The two cases represent a significant milestone.
In the last three years, the milestone for cure has gone up sharply because we have an idea of what would lead to a cure. Antiretroviral therapy does not eliminate the virus from the body completely because the virus hides in some cells, where ARVs don't reach. They can only clear what’s in the blood.
The way HIV cure would happen is that we would start with ARV so when the viral load is down, you knock them down. Then you still keep someone on antiretroviral for some time as you monitor.
The second part is there are 30 million-plus (37 million, according to the Unaids) people with HIV across the world. We can put everyone on ART and incidence will go down, and people will have a normal life expectancy. But the amount of dollars we need to put all these people on treatment for life is too much, so we have sufficient motivation to find treatment.
WHERE EXACTLY ARE WE ON THE JOURNEY OF FINDING A CURE?
We now have a very good understanding of why the virus keeps evading the antiretroviral therapy, and we know where it hides. We have proof of concept that cure is possible.
If you follow both the Berlin and London patient, the thread is similar. If you have a mutation to the gene CCR5 gene, you can’t get HIV, it cannot attach to the cell and so it will be knocked off by ARVs.
The medicines are always circulating in the blood but the ARVs cannot recognise or enter into some of those cells. When a virus has entered a cell, sometimes this cell exposes itself to white blood cells and is killed together with the virus. So sometimes, these hijacked cells hide. It’s like if someone is hijacked by thugs, sometimes they can’t alert cops in case they are shot along with the hijackers.
So there is proof this mutation can be engineered to make the cell become immune to HIV infection. In the entire bloodstream, to find those infected cells that are hiding takes a lot of time, because they are also very few. It could mean one infected cell in a million cells. So if you miss that one and discontinue ART, that one cell will come out and the virus will spread.
People with CCR5 mutation can get still infected but the virus has nowhere to hide, so ART will come and kill them.
SO WHAT DOES THE PROOF OF CONCEPT IMPLY EXACTLY?
Proof of concept means if you follow that line, you can find a cure. You can also use gene therapy. You can just get an injection and this causes a mutation and prevents the cells from infection.
You could even use the antibodies that are there to identify those cells where the virus is hiding. With ARVs we have done 99 per cent of the work, ARVs have done the dirty work. But now you need another compound that will go into those cells and kill them. So the antibodies will go door to door, and if they find a virus they bombard it. I’m putting it in a simplistic way for easy understanding.
The foundation of HIV cure is viral suppression with ART, so you need to clear the circulating viruses completely, then you focus on the spots where they are hiding.
HOW LONG ARE WE TO THE CURE?
There is extreme optimism by the top HIV researchers in the world. Between February 7-9 this year, I joined 30 high-level stakeholders from the HIV scientific, product development, financing and delivery communities for an intimate and vital discussion on prospects and requirements for developing a cure for HIV.
The Sunnylands Summit (held in California) also considered how to ensure the widest possible distribution and access for a future cure. While a cure will be essential worldwide, the primary focus of the retreat was the challenge of distribution in low and lower-middle-income countries, particularly in sub-Saharan Africa.
Of course the reason they involved us in the summit is we will be consumers and we have to provide a product profile. What would be the most effective way to deliver a cure? What’s the cost?
We want something that can be delivered by the lowest cadre of health workers. If we say it’s just doctors, a lot of people will die as we wait. The lowest cadre can deliver an injection; I mean people are even injecting themselves with insulin. It can be something pre-loaded in a syringe and ideally it should be long-acting, so that you don't come every day. You can have your shot and return after three months — those are some of the suggestions we’re giving.
It will take time but the fact that we’re talking of a product profile, shelf life, then you know there's something. Those are the discussions happening and it’s public now.
THERE ARE 1.5 MILLION KENYANS LIVING WITH HIV. WHAT’S YOUR ADVICE TO THEM?
For those living with HIV, the current ARVs are efficacious and enable individuals to live a full life. To that extent, people should continue taking ARVs.
ARVs are the best we have for now, but there are two things: You need to take them for life, and daily. An HIV cure would eliminate that. It will be good for the patient.
The issue of taking the current drugs for life isn't even a patient issue but a donor-and-government issue because we may not have the resources to sustain that. You can imagine how much it would cost to put 30 million people on treatment. It would cost trillions of dollars; we may not have the resources.
But compare that with investing in 10 to 15 years in research, productions and manufacturing; it will be cheaper. The search for HIV cure is a cheaper, better and prudent use of our money. But for now, we cling to ARVs to save lives.