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.
Scientists are studying cancer genomes to more precisely diagnose their patients' diseases - offering hope for targeted drug treatments.
Next, he recalls, he felt ushered into “the jaws of the medical system very quickly.” He spent a couple of days meeting with a team of doctors at Beth Israel Deaconess Medical Center in nearby Boston. One of them was from a medical field he hadn’t even known existed, a pulmonary interventionist, who would perform a biopsy on the mass in his lung.
“Knowing there was a medicine for my particular type of cancer was like a weight lifted off my shoulders."
A week later he and his wife Allison returned to meet with the oncologist, radiologist, pulmonary interventionist – his medical team. They confirmed his initial diagnosis: Stage 4 metastatic lung cancer that had spread to several parts of his body. “We just sat there, stunned,” he says. “I felt like I was getting hit by a wrecking ball over and over.”
An onslaught of medical terminology about what they had identified flowed over the shocked couple, but then the medical team switched gears, he recalls. They offered hope. “They told me, ‘Hey, you’re not a smoker, so that’s good,’” Reiner says. “‘There’s a good chance that what’s driving this disease for you is actually a genetic mutation, and we have ways to understand more about what that could be through some simple testing.’”
They told him about Foundation Medicine, a company launched in neighboring Cambridge, MA, in 2009 that develops, manufactures, and sells genomic profiling assays. These are tests that, according to the company’s website, “can analyze a broad panel of genes to detect the four main classes of genomic alterations known to drive cancer growth.” With these insights, certain patients can be matched with therapies targeted specifically for the genetic driver(s) of their cancer. The company maintains one of the largest cancer genomic databases in the world, with more than 500,000 patient samples profiled, and they have more than 65 biopharma partners.
According to Foundation Medicine, they are the only company that has FDA-approved tests for both tissue- and blood-based comprehensive genomic profiling tests. One other company has an FDA-approved biopsy test, and several other companies offer tissue-based genomic profiling. Additionally, several major cancer centers like Memorial Sloan Kettering in New York and Anderson Cancer Center in Texas have their own such testing platforms.
Currently, genomic profiling is more accessible for patients with advanced cancer, due to broader insurance coverage in later stages of disease.
“Right now, the vast majority of patients either have cancers for which we don’t have treatments or they have genetic alterations that are not known,” says Jorge Garcia, MD, Division Chief, Solid Tumor Oncology, UH Cleveland Medical Center, which has its own CGP testing platform. “However, a significant proportion of patients with advanced cancer have alterations that we can tap for therapeutic purposes.”
Foundation Medicine estimates that in 2017, just over 5 percent of advanced solid cancer patients in the U.S. received CGP testing. In 2021, they estimate that number is between 25 to 30 percent of advanced solid cancer patients in the U.S., which doesn’t include patients who are tested with small (less than 50 genes) panels. Their panel tests for more than 300 cancer-related genes.
“The good news is the platforms we are developing are better and more comprehensive, and they’re going to continue to be larger data sets,” Dr. Garcia adds.
In Reiner’s case, his team ordered comprehensive genetic profiling on both his tissue and blood, from Foundation Medicine.
At this point, Reiner still wasn’t sure what genetic mutations were or how they factored into cancer or what comprehensive genomic profiling entailed. That day, though, his team ushered the Reiners into the world of precision oncology that placed him on much more sure footing to learn about and fight the specific lung cancer that had been troubling him for more than a year.
What genetic alterations were driving his cancer? Foundation Medicine’s tests were about to find out.
At the core of these tests is next generation sequencing, a DNA sequencing technology. Since 2009, this has revolutionized genomic research, according to the National Center for Biotechnology Information, because it allows an entire human genome to be sequenced within one day. Cancer genomics posits that cancer is caused by mutations and is a disease of the genome. Now, cancer genomes can be systemically studied in their entirety. For cancer patients such as Reiner, NGS can provide a more precise diagnosis and classification of the disease, more accurate prognosis, and potentially the identification of targeted drug treatments. Ultimately, the technology can provide the basis of personalized cancer management.
The detailed reports supply patients and their oncologists with extensive information about the patient’s genomic profile and potential treatment options that they can discuss together. Reiner trusted his doctors that this approach was worth the two- or three-week wait to receive the Foundation Medicine report and the specifically targeted treatment, rather than immediately jump into a round of chemotherapy. He is especially grateful now, he says, because the report delivered a great deal of relief from his previously exhausting and growing anxiety about having cancer.
Reiner and his team learned his lung cancer contained the epidermal growth factor receptor (EGFR) mutation. That biomarker enabled his oncologist to prescribe Tagrisso (osimertinib), a medication developed to directly target that genetic mutation.
“Knowing there was a medicine for my particular type of cancer was like a weight lifted off my shoulders,” he says. “It only took a week or two before my cough finally started subsiding. This pill goes right after the particular piece of genetic material in the tumor that’s causing its growth.”
Dr. Jerry Mitchell, director field medical oncology, Foundation Medicine, in Columbus, Ohio, explains that genomic profiling is generating substantial impacts today. “This is a technology that is the standard of care across many advanced malignancies that takes patients from chemotherapy-only options to very targeted options or immunotherapy options,” he says. “You can also look at complex biomarkers, and these are not specific genetic changes but different genes across the tumor to get a biomarker.”
According to Dr. Mitchell, Foundation Medicine’s technology can test more than 324 different cancer-related genes in a single test. Thus, a growing number of patients are benefitting from comprehensive genetic profiling, due to the rapidly growing number of targeted therapies. While not all of the cancers are treatable yet, the company uses that information to partner with researchers to find new potential therapies for patient groups that may have rare mutations.
Since his tumor’s diagnosis, Reiner has undergone chemotherapy and a couple surgeries to treat the metastatic cancer in other parts of his body, but the drug Tagrisso has significantly reduced his lung tumor. Now, having learned so much during the past couple of years, he is grateful for precision oncology. He still reflects on the probability that, had the Tagrisso pill not been available in May 2019, he might have only survived for another six months or a year.
“Comprehensive Genomic Profiling is not some future state, but in both the U.S. and Europe, it is a very standard, accepted, and recommended first step to knowing how to treat your cancer,” says Dr. Mitchell, adding that he feels fortunate to be an oncologist in this era. “However, we know there are still people not getting this recommended testing, so we still have opportunities to find many more patients and impact them by knowing the molecular profile of their cancer.”