A Cure for Sickle Cell Disease Is Coming. Will Patients Accept It?
If any malady proves the fragile grace of the human genome, it is sickle cell disease.
If experimental treatments receive regulatory approval, it would be a watershed breakthrough for tens of thousands of Americans.
It occurs because of a single "misspelled" letter of DNA, causing red blood cells to run low on oxygen and transforming the hemoglobin in each cell into a stiff rod. Normally round cells become rigid crescents that hamper the flow of blood throughout the body, like leaves clumping in a drain.
Strokes in toddlers are merely the beginning of the circulatory calamities this disease may inflict. Most sickled cells cannot carry oxygen through the body, causing anemia as well as excruciating chronic pain. Older patients are at risk of kidney failure, heart disease and all the other collateral damage caused by poor circulation. Few live beyond middle age.
The only way to cure it has been through a bone marrow transplant from a donor, which requires not only a closely matching volunteer, but bouts of chemotherapy to allow new stem cells to take root, as well as rounds of immunosuppressive drugs that may last for years.
Recent advances in genomic medicine may soon alter the disease's outlook, although many obstacles remain.
In one treatment under development, patient's skin cells are converted into stem cells, allowing them to be inserted into the bone marrow without the need for a donor. Another treatment known as gene therapy involves replacing the aberrant gene in the patient's body with new genetic material.
Although both remain in clinical trials -- and also require at least chemotherapy -- they have shown promise. Matthew Hsieh, a hematologist and staff scientist with the National Heart Lung and Blood Institute in Maryland, has performed about 10 gene therapy procedures over the past three years as part of a clinical trial. Ongoing tweaks in the procedure have led to the blood in more recent patients showing sickle cell trait -- not a perfect outcome, but one that leaves patients with far fewer symptoms than if they have the full-blown disease.
If one or both treatments receive regulatory approval, it would be a watershed breakthrough for the tens of thousands of Americans who suffer from the disease.
Yet it is entirely possible many patients may decline the cure.
A Painful History
The vast majority of sickle cell sufferers in the U.S. -- well beyond 90 percent -- are African-American, a population with a historically uneasy relationship toward healthcare.
"There is a lot of data on distrust between African-Americans and American medical institutions," says J. Corey Williams, a psychiatrist with the Children's Hospital of Philadelphia who has written extensively on racial disparities in healthcare. "It comes from a long legacy of feeling victimized by medicine."
"What you hear from many patients is 'I am not going to be your guinea pig, and I am not going to be experimented on.'"
As a result, Williams is among several clinicians interviewed for this story who believe a cure for sickle cell disease would be embraced reluctantly.
"What you hear from many patients is 'I am not going to be your guinea pig, and I am not going to be experimented on.' And so the history of African-Americans and research will manifest as we develop gene therapies for [these] patients," says Christopher L. Edwards, a clinical psychologist and researcher with the Maya Angelou Center for Health Equity at the Wake Forest University School of Medicine.
Fear among African-Americans of becoming guinea pigs is well-founded. The first c-sections and fistula repairs occurring in North America were performed on enslaved women -- all without consent and virtually none with anesthesia.
Modern 20th century medicine led to the Tuskegee syphilis experiments conducted by the U.S. Public Health Service. Researchers withheld treatment from some 400 African-American men from the 1930s well into the 1970s to observe how they reacted to the disease -- even though curative antibiotics had been around for decades. Only news reports ended the experiment.
The long-standing distrust of American healthcare in the African-American community is also baked into the care provided to sickle cell patients. Despite affecting one in 365 African-Americans, there is no disease registry to assist clinical trials, according to Mary Hulihan, a blood disorders epidemiologist with the Centers for Disease Control and Prevention. Edwards says many sufferers are suspicious of being monitored.
Meanwhile, only two drugs are available to alleviate the worst symptoms. The first one, hydroxyurea, received FDA approval only in 1998 -- nearly 90 years after the disease was first diagnosed. Moreover, Edwards says that some sufferers shy away from using hydroxyurea because it is also used to treat cancer. It's part of what he calls the "myth and folklore" in the African-American community about sickle cell disease.
Economics plays a role as well in the often-fragmented care such patients receive. According to CDC data, many patients rely extensively on public insurance programs such as Medicaid, whose coverage varies from state to state.
A Tough Transition
Edwards notes that sickle cell sufferers usually receive good care when they're children because of support provided by family members. But that often breaks down in adulthood. According to CDC data, an adult sickle cell patient visits a hospital emergency room three times as often as a child patient.
The consensus is that the path to a medical cure for sickle cell will first need to be smoothed over with a talk cure.
Modupe Idowu, a hematologist with the University of Texas Health system, estimates that there are perhaps a dozen comprehensive care centers for the estimated 100,000 sickle cell patients in the U.S., including the one she operates in Houston. That means a significant proportion of those afflicted are on their own to procure care.
And since many patients are on Medicaid, "a lot of hematologists that train to take care of blood disorders, many are not interested in treating [sickle cell disease] because the reimbursement for providers is not great," Idowu says.
Hsieh acknowledges that many of his patients can be suspicious about the care they are receiving. Frustration with fragmented care is usually the biggest driver, he adds.
Meanwhile, the skepticism that patients have about the treatments they seek is often reciprocated by their caregivers.
"The patients have experiences with medication and know what works at a very young age (for their pain)," Edwards says. Such expertise demonstrated by an African-American patient often leads to them being labeled as narcotics seekers.
The Correct Path
This all begs the question of how to deploy a cure. Idowu, who regularly holds town hall-style meetings with Houston-area patients, often must allay anxieties. For example, the gene therapy approach uses a harmless virus to transport new genetic material into cells. That virus happens to be a benign version of HIV, and convincing patients they won't be infected with HIV is a fraught issue.
The consensus is that the path to a medical cure for sickle cell will first need to be smoothed over with a talk cure.
Idowu tries to hammer home the fact that patients are afforded vastly more protections than in the past. "There are a lot of committees and investigational review boards that keep track of clinical trials; things just don't happen anymore as they did in the past," she says. She also believes it helps if more providers of color communicate to patients.
Hsieh is very straightforward with his patients. He informs them about the HIV vector but assures them no one has ever tested positive for the virus as a result of its use.
Edwards notes that since many patients suffer psychosocial trauma as a result of their chronic pain, there already is some counseling infrastructure in place to help them cope. He believes such resources will have to be stretched further as a cure looms closer.
In the absence of formal mental health services, straight talk may be the best way to overcome wariness.
"If patients have misgivings, we try our best to address them, and let them know at the end of the day it is their decision to make," Hsieh says. "And even the patients who have gone through the gene therapy and it didn't work well -- they're still glad they took the chance."
Meet Dr. Renee Wegrzyn, the first Director of President Biden's new health agency, ARPA-H
In today’s podcast episode, I talk with Renee Wegrzyn, appointed by President Biden as the first director of a health agency created last year, the Advanced Research Projects Agency for Health, or ARPA-H. It’s inspired by DARPA, the agency that develops innovations for the Defense department and has been credited with hatching world-changing technologies such as ARPANET, which became the internet.
Time will tell if ARPA-H will lead to similar achievements in the realm of health. That’s what President Biden and Congress expect in return for funding ARPA-H at 2.5 billion dollars over three years.
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How will the agency figure out which projects to take on, especially with so many patient advocates for different diseases demanding moonshot funding for rapid progress?
I talked with Dr. Wegrzyn about the opportunities and challenges, what lessons ARPA-H is borrowing from Operation Warp Speed, how she decided on the first ARPA-H project that was announced recently, why a separate agency was needed instead of reforming HHS and the National Institutes of Health to be better at innovation, and how ARPA-H will make progress on disease prevention in addition to treatments for cancer, Alzheimer’s and diabetes, among many other health priorities.
Dr. Wegrzyn’s resume leaves no doubt of her suitability for this role. She was a program manager at DARPA where she focused on applying gene editing and synthetic biology to the goal of improving biosecurity. For her work there, she received the Superior Public Service Medal and, in case that wasn’t enough ARPA experience, she also worked at another ARPA that leads advanced projects in intelligence, called I-ARPA. Before that, she ran technical teams in the private sector working on gene therapies and disease diagnostics, among other areas. She has been a vice president of business development at Gingko Bioworks and headed innovation at Concentric by Gingko. Her training and education includes a PhD and undergraduate degree in applied biology from the Georgia Institute of Technology and she did her postdoc as an Alexander von Humboldt Fellow in Heidelberg, Germany.
Dr. Wegrzyn told me that she’s “in the hot seat.” The pressure is on for ARPA-H especially after the need and potential for health innovation was spot lit by the pandemic and the unprecedented speed of vaccine development. We'll soon find out if ARPA-H can produce gamechangers in health that are equivalent to DARPA’s creation of the internet.
Show links:
ARPA-H - https://arpa-h.gov/
Dr. Wegrzyn profile - https://arpa-h.gov/people/renee-wegrzyn/
Dr. Wegrzyn Twitter - https://twitter.com/rwegrzyn?lang=en
President Biden Announces Dr. Wegrzyn's appointment - https://www.whitehouse.gov/briefing-room/statement...
Leaps.org coverage of ARPA-H - https://leaps.org/arpa/
ARPA-H program for joints to heal themselves - https://arpa-h.gov/news/nitro/ -
ARPA-H virtual talent search - https://arpa-h.gov/news/aco-talent-search/
Dr. Renee Wegrzyn was appointed director of ARPA-H last October.
Tiny, tough “water bears” may help bring new vaccines and medicines to sub-Saharan Africa
Microscopic tardigrades, widely considered to be some of the toughest animals on earth, can survive for decades without oxygen or water and are thought to have lived through a crash-landing on the moon. Also known as water bears, they survive by fully dehydrating and later rehydrating themselves – a feat only a few animals can accomplish. Now scientists are harnessing tardigrades’ talents to make medicines that can be dried and stored at ambient temperatures and later rehydrated for use—instead of being kept refrigerated or frozen.
Many biologics—pharmaceutical products made by using living cells or synthesized from biological sources—require refrigeration, which isn’t always available in many remote locales or places with unreliable electricity. These products include mRNA and other vaccines, monoclonal antibodies and immuno-therapies for cancer, rheumatoid arthritis and other conditions. Cooling is also needed for medicines for blood clotting disorders like hemophilia and for trauma patients.
Formulating biologics to withstand drying and hot temperatures has been the holy grail for pharmaceutical researchers for decades. It’s a hard feat to manage. “Biologic pharmaceuticals are highly efficacious, but many are inherently unstable,” says Thomas Boothby, assistant professor of molecular biology at University of Wyoming. Therefore, during storage and shipping, they must be refrigerated at 2 to 8 degrees Celsius (35 to 46 degrees Fahrenheit). Some must be frozen, typically at -20 degrees Celsius, but sometimes as low -90 degrees Celsius as was the case with the Pfizer Covid vaccine.
For Covid, fewer than 73 percent of the global population received even one dose. The need for refrigerated or frozen handling was partially to blame.
The costly cold chain
The logistics network that ensures those temperature requirements are met from production to administration is called the cold chain. This cold chain network is often unreliable or entirely lacking in remote, rural areas in developing nations that have malfunctioning electrical grids. “Almost all routine vaccines require a cold chain,” says Christopher Fox, senior vice president of formulations at the Access to Advanced Health Institute. But when the power goes out, so does refrigeration, putting refrigerated or frozen medical products at risk. Consequently, the mRNA vaccines developed for Covid-19 and other conditions, as well as more traditional vaccines for cholera, tetanus and other diseases, often can’t be delivered to the most remote parts of the world.
To understand the scope of the challenge, consider this: In the U.S., more than 984 million doses of Covid-19 vaccine have been distributed so far. Each one needed refrigeration that, even in the U.S., proved challenging. Now extrapolate to all vaccines and the entire world. For Covid, fewer than 73 percent of the global population received even one dose. The need for refrigerated or frozen handling was partially to blame.
Globally, the cold chain packaging market is valued at over $15 billion and is expected to exceed $60 billion by 2033.
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Freeze-drying, also called lyophilization, which is common for many vaccines, isn’t always an option. Many freeze-dried vaccines still need refrigeration, and even medicines approved for storage at ambient temperatures break down in the heat of sub-Saharan Africa. “Even in a freeze-dried state, biologics often will undergo partial rehydration and dehydration, which can be extremely damaging,” Boothby explains.
The cold chain is also very expensive to maintain. The global pharmaceutical cold chain packaging market is valued at more than $15 billion, and is expected to exceed $60 billion by 2033, according to a report by Future Market Insights. This cost is only expected to grow. According to the consulting company Accenture, the number of medicines that require the cold chain are expected to grow by 48 percent, compared to only 21 percent for non-cold-chain therapies.
Tardigrades to the rescue
Tardigrades are only about a millimeter long – with four legs and claws, and they lumber around like bears, thus their nickname – but could provide a big solution. “Tardigrades are unique in the animal kingdom, in that they’re able to survive a vast array of environmental insults,” says Boothby, the Wyoming professor. “They can be dried out, frozen, heated past the boiling point of water and irradiated at levels that are thousands of times more than you or I could survive.” So, his team is gradually unlocking tardigrades’ survival secrets and applying them to biologic pharmaceuticals to make them withstand both extreme heat and desiccation without losing efficacy.
Boothby’s team is focusing on blood clotting factor VIII, which, as the name implies, causes blood to clot. Currently, Boothby is concentrating on the so-called cytoplasmic abundant heat soluble (CAHS) protein family, which is found only in tardigrades, protecting them when they dry out. “We showed we can desiccate a biologic (blood clotting factor VIII, a key clotting component) in the presence of tardigrade proteins,” he says—without losing any of its effectiveness.
The researchers mixed the tardigrade protein with the blood clotting factor and then dried and rehydrated that substance six times without damaging the latter. This suggests that biologics protected with tardigrade proteins can withstand real-world fluctuations in humidity.
Furthermore, Boothby’s team found that when the blood clotting factor was dried and stabilized with tardigrade proteins, it retained its efficacy at temperatures as high as 95 degrees Celsius. That’s over 200 degrees Fahrenheit, much hotter than the 58 degrees Celsius that the World Meteorological Organization lists as the hottest recorded air temperature on earth. In contrast, without the protein, the blood clotting factor degraded significantly. The team published their findings in the journal Nature in March.
Although tardigrades rarely live more than 2.5 years, they have survived in a desiccated state for up to two decades, according to Animal Diversity Web. This suggests that tardigrades’ CAHS protein can protect biologic pharmaceuticals nearly indefinitely without refrigeration or freezing, which makes it significantly easier to deliver them in locations where refrigeration is unreliable or doesn’t exist.
The tricks of the tardigrades
Besides the CAHS proteins, tardigrades rely on a type of sugar called trehalose and some other protectants. So, rather than drying up, their cells solidify into rigid, glass-like structures. As that happens, viscosity between cells increases, thereby slowing their biological functions so much that they all but stop.
Now Boothby is combining CAHS D, one of the proteins in the CAHS family, with trehalose. He found that CAHS D and trehalose each protected proteins through repeated drying and rehydrating cycles. They also work synergistically, which means that together they might stabilize biologics under a variety of dry storage conditions.
“We’re finding the protective effect is not just additive but actually is synergistic,” he says. “We’re keen to see if something like that also holds true with different protein combinations.” If so, combinations could possibly protect against a variety of conditions.
Commercialization outlook
Before any stabilization technology for biologics can be commercialized, it first must be approved by the appropriate regulators. In the U.S., that’s the U.S. Food and Drug Administration. Developing a new formulation would require clinical testing and vast numbers of participants. So existing vaccines and biologics likely won’t be re-formulated for dry storage. “Many were developed decades ago,” says Fox. “They‘re not going to be reformulated into thermo-stable vaccines overnight,” if ever, he predicts.
Extending stability outside the cold chain, even for a few days, can have profound health, environmental and economic benefits.
Instead, this technology is most likely to be used for the new products and formulations that are just being created. New and improved vaccines will be the first to benefit. Good candidates include the plethora of mRNA vaccines, as well as biologic pharmaceuticals for neglected diseases that affect parts of the world where reliable cold chain is difficult to maintain, Boothby says. Some examples include new, more effective vaccines for malaria and for pathogenic Escherichia coli, which causes diarrhea.
Tallying up the benefits
Extending stability outside the cold chain, even for a few days, can have profound health, environmental and economic benefits. For instance, MenAfriVac, a meningitis vaccine (without tardigrade proteins) developed for sub-Saharan Africa, can be stored at up to 40 degrees Celsius for four days before administration. “If you have a few days where you don’t need to maintain the cold chain, it’s easier to transport vaccines to remote areas,” Fox says, where refrigeration does not exist or is not reliable.
Better health is an obvious benefit. MenAfriVac reduced suspected meningitis cases by 57 percent in the overall population and more than 99 percent among vaccinated individuals.
Lower healthcare costs are another benefit. One study done in Togo found that the cold chain-related costs increased the per dose vaccine price up to 11-fold. The ability to ship the vaccines using the usual cold chain, but transporting them at ambient temperatures for the final few days cut the cost in half.
There are environmental benefits, too, such as reducing fuel consumption and greenhouse gas emissions. Cold chain transports consume 20 percent more fuel than non-cold chain shipping, due to refrigeration equipment, according to the International Trade Administration.
A study by researchers at Johns Hopkins University compared the greenhouse gas emissions of the new, oral Vaxart COVID-19 vaccine (which doesn’t require refrigeration) with four intramuscular vaccines (which require refrigeration or freezing). While the Vaxart vaccine is still in clinical trials, the study found that “up to 82.25 million kilograms of CO2 could be averted by using oral vaccines in the U.S. alone.” That is akin to taking 17,700 vehicles out of service for one year.
Although tardigrades’ protective proteins won’t be a component of biologic pharmaceutics for several years, scientists are proving that this approach is viable. They are hopeful that a day will come when vaccines and biologics can be delivered anywhere in the world without needing refrigerators or freezers en route.