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.
Sarah Watts's son Henry was born with spina bifida and can't stand or walk without assistance.
When our son Henry, now six, was diagnosed with spina bifida at his 20-week ultrasound, my husband and I were in shock. It took us more than a few minutes to understand what the doctor was telling us.
When Henry was diagnosed in 2012, postnatal surgery was still the standard of care – but that was about to change.
Neither of us had any family history of birth defects. Our fifteen-month-old daughter, June, was in perfect health.
But more than that, spina bifida – a malformation of the neural tube that eventually becomes the baby's spine – is woefully complex. The defect, the doctor explained, was essentially a hole in Henry's lower spine from which his spinal nerves were protruding – and because they were exposed to my amniotic fluid, those nerves were already permanently damaged. After birth, doctors could push the nerves back into his body and sew up the hole, but he would likely experience some level of paralysis, bladder and bowel dysfunction, and a buildup of cerebrospinal fluid that would require a surgical implant called a shunt to correct. The damage was devastating – and irreversible.
We returned home with June and spent the next few days cycling between disbelief and total despair. But within a week, the maternal-fetal medicine specialist who diagnosed Henry called us up and gave us the first real optimism we had felt in days: There was a new, experimental surgery for spina bifida that was available in just a handful of hospitals around the country. Rather than waiting until birth to repair the baby's defect, some doctors were now trying out a prenatal repair, operating on the baby via c-section, closing the defect, and then keeping the mother on strict bedrest until it was time for the baby to be delivered, just before term.
This new surgery carried risks, he told us – but if it went well, there was a chance Henry wouldn't need a shunt. And because repairing the defect during my pregnancy meant the spinal nerves were exposed for a shorter amount of time, that meant we'd be preventing nerve damage – and less nerve damage meant that there was a chance he'd be able to walk.
Did we want in? the doctor asked.
Had I known more about spina bifida and the history of its treatment, this surgery would have seemed even more miraculous. Not too long ago, the standard of care for babies born with spina bifida was to simply let them die without medical treatment. In fact, it wasn't until the early 1950s that doctors even attempted to surgically repair the baby's defect at all, instead of opting to let the more severe cases die of meningitis from their open wound. (Babies who had closed spina bifida – a spinal defect covered by skin – sometimes survived past infancy, but rarely into adulthood).
But in the 1960s and 1970s, as more doctors started repairing defects and the shunting technology improved, patients with spina bifida began to survive past infancy. When catheterization was introduced, spina bifida patients who had urinary dysfunction, as is common, were able to preserve their renal function into adulthood, and they began living even longer. Within a few decades, spina bifida was no longer considered a death sentence; people were living fuller, happier lives.
When Henry was diagnosed in 2012, postnatal surgery was still the standard of care – but that was about to change. The first major clinical trial for prenatal surgery and spina bifida, called Management of Myelomeningocele (MOMS) had just concluded, and its objective was to see whether repairing the baby's defect in utero would be beneficial. In the trial, doctors assigned eligible women to undergo prenatal surgery in the second trimester of their pregnancies and then followed up with their children throughout the first 30 months of the child's life.
The results were groundbreaking: Not only did the children in the surgery group perform better on motor skills and cognitive tests than did patients in the control group, only 40 percent of patients ended up needing shunts compared to 80 percent of patients who had postnatal surgery. The results were so overwhelmingly positive that the trial was discontinued early (and is now, happily, the medical standard of care). Our doctor relayed this information to us over the phone, breathless, and left my husband and me to make our decision.
After a few days of consideration, and despite the benefits, my husband and I actually ended up opting for the postnatal surgery instead. Prenatal surgery, although miraculous, would have required extensive travel for us, as well as giving birth in a city thousands of miles from home with no one to watch our toddler while my husband worked and I recovered. But other parents I met online throughout our pregnancy did end up choosing prenatal surgery for their children – and the majority of them now walk with little assistance and only a few require shunting.
Even more amazing to me is that now – seven years after Henry's diagnosis, and not quite a decade since the landmark MOMS trial – the standard of care could be about to change yet again.
Regardless of whether they have postnatal or prenatal surgery, most kids with spina bifida still experience some level of paralysis and rely on wheelchairs and walkers to move around. Now, researchers at UC Davis want to augment the fetal surgery with a stem cell treatment, using human placenta-derived mesenchymal stromal cells (PMSCs) and affixing them to a cellular scaffold on the baby's defect, which not only protects the spinal cord from further damage but actually encourages cellular regeneration as well.
The hope is that this treatment will restore gross motor function after the baby is born – and so far, in animal trials, that's exactly what's happening. Fetal sheep, who were induced with spinal cord injuries in utero, were born with complete motor function after receiving prenatal surgery and PMSCs. In 2017, a pair of bulldogs born with spina bifida received the stem cell treatment a few weeks after birth – and two months after surgery, both dogs could run and play freely, whereas before they had dragged their hind legs on the ground behind them. UC Davis researchers hope to bring this treatment into human clinical trials within the next year.
A century ago, a diagnosis of spina bifida meant almost certain death. Today, most children with spina bifida live into adulthood, albeit with significant disabilities. But thanks to research and innovation, it's entirely possible that within my lifetime – and certainly within Henry's – for the first time in human history, the disabilities associated with spina bifida could be a thing of the past.
Dr. Andrew Brooks of RUCDR Infinite Biologics holds up a saliva sample.
The patient tilts back her head and winces as the long swab stick pushes six inches up her nose. The tip twirls around uncomfortably before it's withdrawn.
"Our saliva test can detect the virus in asymptomatic and pre-symptomatic cases."
A gloved and gowned healthcare worker wearing a face shield and mask tells the patient that she will learn whether she is positive for COVID-19 as soon as the lab can process her test.
This is the typical unpleasant scenario for getting a coronavirus test. But times are rapidly changing: Today, for the first time, the U.S. Food and Drug Administration cleared one company to sell saliva collection kits for individuals to use at home.
Scientists at the startup venture, RUCDR Infinite Biologics at Rutgers University in New Jersey, say that saliva testing offers an easier, more useful alternative to the standard nasal swab.
"Our saliva test can detect the virus in asymptomatic and pre-symptomatic cases," said Dr. Andrew Brooks, chief operating officer at RUCDR.
Another venture, Darwin BioSciences in Colorado, has separately developed an innovative method of testing saliva for the coronavirus that causes COVID-19.
Saliva testing can allow earlier detection to identify people who may not know they are contagious, say scientists at both companies. In addition, because patients spit into a tube or cup, saliva testing is safer for healthcare workers than taking swabs. This frees up scarce personal protective equipment (PPE) for use elsewhere. Nasal swabs themselves have been in scarce supply.
Saliva testing, if it becomes widespread, potentially could mean opening society sooner. The more ubiquitous testing becomes across the population, experts say, the more feasible it becomes for public health officials to trace and isolate contacts, especially of asymptomatic cases. Testing early and often will be essential to containing emerging hot spots before a vast outbreak can take root.
Darwin Biosceiences is preparing to seek an FDA Emergency Use Authorization (EUA) this month for its patented "CoVScreen" testing system, which potentially could be available to labs nationally by mid-summer.
Meanwhile, Infinite Biologics will now begin selling kits to consumers for home collection, upon order by a physician. The FDA said that the company's saliva test was as accurate as the nasal swab method used by health care professionals. An FDA summary documenting the company's data reported: "There was 100% positive and negative agreement between the results obtained from testing of saliva and those obtained from nasopharyngeal and oropharyngeal swabs."
The greatest scientific advantage, said Dr. Brooks, is that nasal and oral swabs only collect the surface area where the swab goes, which may not be the place with most viral load. In contrast, the virus occurs throughout a saliva sample, so the test is more trustworthy.
The lab at Rutgers can process 20,000 tests a day, with a 48-hour turnaround. They have 75,000 tests ready to ship now.
The Leap: Detecting Sickness Before You Feel It
"We wanted to create a device that could detect infections before symptoms appeared," explained Nicholas Meyerson, co-founder and CEO of Darwin.
For more than 300 years, he said, "the thermometer was the gold standard for detecting disease because we thought the first sign of illness was a fever. This COVID-19 pandemic has proven that not all pathogens cause a fever. You can be highly contagious without knowing it."
"The question is whether we can scale up fast enough to meet the need. I believe saliva testing can help."
Therefore, Meyerson and co-founder Sara Sawyer from the University of Colorado began to identify RNA biomarkers that can sense when a pathogen first enters a molecule and "sets off alarms." They focused on the nucleic acids concentrated in saliva as the best and easiest place to collect samples for testing.
"The isothermal reaction in saliva takes place at body or room temperature," he said, "so there's no need for complicated testing machinery. The chemical reaction can be read out on a paper strip, like a pregnancy test -- two stripes if you're sick, and one stripe if you're okay."
Before the pandemic, limited but successful human trials were already underway at CU in Boulder and at the CU Anschutz Medical Campus east of Denver. "This was our proof of concept," he said.
Darwin was founded in March and has secured enough venture capital to concentrate protype development on detecting the virus causing COVID-19. So far, said Meyerson, "Everything works."
A small double-blind test of 30 samples at CU produced 100 percent accuracy. "I'm not sure if that will hold true as we go into clinical trials," he said, "but I'm confident we will satisfy all the requirements for at least 95 percent clinical validation."
The specific "CoVStick" test strips will roll out soon, he said: "We hope before the second wave of the pandemic hits."
The broader saliva test-strip product from Darwin, "SickStick," is still one to two years away from deployment by the military and introduction into the consumer drugstore market for home use, said Meyerson. It will affordably and quickly detect a range of viral and bacterial infections.
An illustration of the "CoVStick."
(Darwin Biosciences)
A Potential Game Changer
Society needs widespread testing daily, said George Church, founding core faculty of the Wyss Institute for Biologically Inspired Engineering at Harvard University. Speaking at an online SynBioBeta webinar in April, he urged developing stockpiles of testing kits for home use.
As for any potential of false positives, Church said a much bigger risk is not having enough tests.
"Saliva testing is going to speed up the timeline for opening society a lot," said Meyerson. "People need to self-collect samples at home. A lot more people are going to be willing to spit into a tube than to push a swab six inches up their own nose."
Brooks, of Rutgers, addressed the big picture. "It's critical that we open society as soon as possible to minimize the economic impact of the pandemic. Testing is the surest and safest path. The question is whether we can scale up fast enough to meet the need. I believe saliva testing can help."