A blood test for analysis of HIV.
Last week, top experts on HIV/AIDS convened in Amsterdam for the 22nd International AIDS conference, and the mood was not great. Even though remarkable advances in treating HIV have led to effective management for many people living with the disease, and its overall incidence has declined, there are signs that the virus could make a troubling comeback.
"In a perfect world, we'd get a vaccine like the HPV vaccine that was 100% effective and I think that's ultimately what we're going to strive for."
Growing resistance to current HIV drugs, a population boom in Sub-Saharan Africa, and insufficient public health resources are all poised to contribute to a second AIDS pandemic, according to published reports.
Already, the virus is nowhere near under control. Though the infection rate has declined 47 percent since its peak in 1996, last year 1.8 million people became newly infected with HIV around the world, and 37 million people are currently living with it. About 1 million people die of AIDS every year, making it the fourth biggest killer in low-income countries.
Leapsmag Editor-in-Chief Kira Peikoff reached out to Dr. Carl Dieffenbach, Director of the Division of AIDS at the National Institute of Allergy and Infectious Diseases, to find out what the U.S. government is doing to develop an HIV vaccine and cure. This interview has been edited and condensed for clarity.
What is the general trajectory of research in HIV/AIDS today?
We can break it down to two specific domains: focus on treatment and cure, and prevention.
Let's start with people living with HIV. This is the area where we've had the most success over the past 30 plus years, because we've taken a disease that was essentially a death sentence and converted it through the development of medications to a treatable chronic disease.
The second half of this equation is, can we cure or create a functional cure for people living with HIV? And the definition of functional cure would be the absence of circulating virus in the body in the absence of therapy. Essentially the human body would control the HIV infection within the individual. That is a much more, very early research stage of discovery. There are some interesting signals but it's still in need of innovation.
I'd like to make a contrast between what we are able to do with a virus called Hepatitis C and what we can do with the virus HIV. Hep C, with 12 weeks of highly active antiviral therapy, we can cure 95 to 100% of infections. With HIV, we cannot do that. The difference is the behavior of the virus. HIV integrates into the host's genome. Hep C is an RNA virus that stays in the cytoplasm of the cell and never gets into the DNA.
On the prevention side, we have two strategies: The first is pre-exposure prophylaxis. Then of course, we have the need for a safe, effective and durable HIV vaccine, which is a very active area of discovery. We've had some spectacular success with RV144, and we're following up on that success, and other vaccines are in the pipeline. Whether they are sufficient to provide the level of durability and activity is not yet clear, but progress has been made and there's still the need for innovation.
The most important breakthrough in the past 5 to 10 years has been the discovery of broad neutralizing monoclonal antibodies. They are proteins that the body makes, and not everybody who's HIV infected makes these antibodies, but we've been able to clone out these antibodies from certain individuals that are highly potent, and when used either singly or in combination, can truly neutralize the vast majority of HIV strains. Can those be used by themselves as treatment or as prevention? That is the question.
Can you explain more about RV144 and why you consider it a success?
Prior to RV144, we had run a number of vaccine studies and nothing had ever statistically shown to be protective. RV144 showed a level of efficacy of about 31 percent, which was statistically significant. Not enough to take forward into other studies, but it allowed us to generate some ideas about why this worked, go back to the drawing board, and redesign the immunogens to optimize and test the next generation for this vaccine. We just recently opened that new study, the follow-up to RV144, called HVTN702. That's up and enrolling and moving along quite nicely.
Carl Dieffenbach, Director of the Division of AIDS at the National Institute of Allergy and Infectious Diseases
(Courtesy)
Where is that enrolling?
Primarily in Sub-Saharan Africa and South Africa.
When will you expect to see signals from that?
Between 2020 and 2021. It's complicated because the signal also takes into account the durability. After a certain time of vaccination, we're going to count up endpoints.
How would you explain the main scientific obstacle in the way of creating a very efficacious HIV vaccine?
Simply put, it's the black box of the human immune system. HIV employs a shield technology, and the virus is constantly changing its shield to protect itself, but there are some key parts of the virus that it cannot shield, so that's the trick – to be able to target that.
So, you're trying to find the Achilles' Heel of the virus?
Exactly. To make a flu vaccine or a Zika vaccine or even an Ebola vaccine, the virus is a little bit more forthcoming with the target. In HIV, the virus does everything in its power to hide the target, so we're dealing with a well-adapted [adversary] that actively avoids neutralization. That's the scientific challenge we face.
What's next?
On the vaccine side, we are currently performing, in collaboration with partners, two vaccine trials – HVTN702, which we talked about, and another one called 705. If either of those are highly successful, they would both require an additional phase 3 clinical trial before they could be licensed. This is an important but not final step. Then we would move into scale up to global vaccination. Those conversations have begun but they are not very far along and need additional attention.
What percent of people in the current trials would need to be protected to move on to phase 3?
Between 50 and 60 percent. That comes with this question of durability: how long does the vaccine last?
It also includes, can we simplify the vaccine regimen? The vaccines we're testing right now are multiple shots over a period of time. Can we get more like the polio or smallpox vaccine, a shot with a booster down the road?
We're dealing with sovereign nations. We're doing this in partnership, not as helicopter-type researchers.
If these current trials pan out, do you think kids in the developed world will end up getting an HIV vaccine one day? Or just people in-at risk areas?
That's a good question. I don't have an answer to that. In a perfect world, we'd get a vaccine like the HPV vaccine that was 100% effective and I think that's ultimately what we're going to strive for. That's where that second or third generation of vaccines that trigger broad neutralizing antibodies come in.
With any luck at all, globally, the combination of antiretroviral treatment, pre-exposure prophylaxis and other prevention and treatment strategies will lower the incidence rate where the HIV pandemic continues to wane, and we will then be able to either target the vaccine or roll it out in a way that is both cost effective and destigmatizing.
And also, what does the country want? We're dealing with sovereign nations. We're doing this in partnership, not as helicopter-type researchers.
How close do you think we are globally to eradicating HIV infections?
Eradication's a big word. It means no new infections. We are nowhere close to eradicating HIV. Whether or not we can continue to bend the curve on the epidemic and have less infections so that the total number of people continues to decline over time, I think we can achieve that if we had the political will. And that's not just the U.S. political will. That's the will of the world. We have the tools, albeit they're not perfect. But that's where a vaccine that is efficacious and simple to deliver could be the gamechanger.
Puschel Sorensen undergoing physical therapy using Cyberdyne's hybrid assistive limb, left, and with her grandson while still in a wheelchair.
Puschel Sorensen first noticed something was wrong when her fingertips began to tingle. Later that day, she grew weak and fell.
It picked up small electrical impulses on her skin's surface and turned them into full movement in her legs.
Her family rushed her to the doctor, where she received the devastating diagnosis of Guillain-Barré Syndrome -- a rare and rapidly progressing autoimmune disorder that attacks the myelin sheath covering nerves.
Sorensen, a once-spry grandmother in her late fifties, spent 54 days in intensive care in 2018. When she was finally transferred to a rehab facility near her home in Florida, she was still on a feeding tube and ventilator, and was paralyzed from the neck down. Progress with traditional physical therapy was slow.
Sorensen in the hospital after her diagnosis of Guillain-Barré syndrome.
And then everything changed. Sorensen began using a cutting-edge technology called an exoskeleton to relearn how to walk. In the vein of Iron Man's fictional power suit, it confers strength and mobility to the wearer that isn't possible otherwise. In Sorensen's case, her device, called HAL – for hybrid assistive limb -- picked up small electrical impulses on her skin's surface and turned them into full movement in her legs while she attempted to walk on a treadmill.
"It was very difficult, but super awesome," recalls Sorensen, of first using the device. "The robot was having to do all the work for me."
Amazingly, within a year, she was running. She's one of 38 patients who have used HAL to recover from accidents or medical catastrophes.
"How do you thank someone for giving them back the ability to walk, the ability to live your life again?" Sorensen asks effusively.
It's still early days for such exoskeleton devices, which number perhaps a few thousand worldwide, according to data from the handful of manufacturers who create them with any scale. But the devices' ability to dramatically rehabilitate patients like Sorensen highlights their potential to extract untold numbers of people from wheelchairs, and even to usher in a new paradigm for caregiving – one of the fastest growing segments of the U.S. economy.
"I've been a physical therapist for 16 years, and (these devices) help teach patients the right way to move in rehabilitation," says Robert McIver, director of clinical technology at the Brooks Cybernic Treatment Center, part of the Brooks Rehabilitation Hospital in Jacksonville, Fla, where Sorensen recovered.
Another patient there, a 17-year-old named George with a snowboarding injury that paralyzed his legs, was getting around with a walker within 20 sessions.
As patients progress in their recoveries, so does exoskeleton technology. Jack Peurach, CEO of Ekso, one of the leaders in the space, believes within a decade they could resemble an article of clothing (a "magic pair of pants" is his phrase). They also may become inexpensive and reliable enough to transition from a medical to a consumer device. McIver sees them eventually being used in the home on an ongoing basis as a personal assistive device, much like a walker or cane, to prevent falls in elderly people.
Such a transition "certainly could eventually lessen the need for caregivers," says Sharona Hoffman, a professor of law at Case Western University in Cleveland who has written extensively on aging and bioethics. "We have a real shortage of caregivers, so that would be a good thing."
Of course, having an aging and disabled population using exoskeletons in much the same way as an Apple Watch raises issues of its own.
Dr. Elizabeth Landsverk, a California-based geriatrician and founder of a company that performs house calls for elderly patients, believes the tech holds some promise in easing the burden on caregivers, who sometimes have to lift or move patients without assistance. But she also believes exoskeletons could become overhyped.
"I don't see robotics as completely replacing the caregiver," she says. And even if exoskeletons became akin to articles of clothing, she is skeptical of how convenient they could become.
"It's hard enough to get into support hose. Would an older person be able to get in and out of it on their own?" she asks, noting that a patient's cognitive levels could pose a huge barrier to donning such a device without assistance.
If personal exoskeletons did wildly succeed, Hoffman wonders whether they would leave the elderly more physically mobile yet also more socially isolated, since caregivers or even residing in an assisted living facility may no longer be required. Or, if they were priced in the hundreds or thousands of dollars, he worries that the cost would exacerbate social inequalities among the elderly and disabled.
"It's almost like a bad dream that [my illness] happened."
With any technology that confers superhuman ability, there's also the question of appropriate usage. Even the fictional Power Loader in the movie Alien required an operator's license. In the real world, such an approach would likely pay dividends.
"We would have to make sure physicians are well-trained in these devices, and patients have a way of getting training to operate them that is thorough and responsible," Hoffman says.
But despite some unresolved questions, it is a remarkable achievement to be able to give people back their lives thanks to new technology.
"It's almost like a bad dream that [my illness] happened," says Sorensen, who managed to walk in her daughter's wedding after her recovery. "Because now everything is pretty much back to normal and it's awesome."
