New Hope for Organ Transplantation: Life Without Anti-Rejection Drugs
Rob Waddell dreaded getting a kidney transplant. He suffers from a genetic condition called polycystic kidney disease that causes the uncontrolled growth of cysts that gradually choke off kidney function. The inherited defect has haunted his family for generations, killing his great grandmother, grandmother, and numerous cousins, aunts and uncles.
But he saw how difficult it was for his mother and sister, who also suffer from this condition, to live with the side effects of the drugs they needed to take to prevent organ rejection, which can cause diabetes, high blood pressure and cancer, and even kidney failure because of their toxicity. Many of his relatives followed the same course, says Waddell: "They were all on dialysis, then a transplant and ended up usually dying from cancers caused by the medications."
When the Louisville native and father of four hit 40, his kidneys barely functioned and the only alternative was either a transplant or the slow death of dialysis. But in 2009, when Waddell heard about an experimental procedure that could eliminate the need for taking antirejection drugs, he jumped at the chance to be their first patient. Devised by scientists at the University of Louisville and Northwestern University, the innovative approach entails mixing stem cells from the live kidney donor with that of the recipient to create a hybrid immune system, known as a chimera, that would trick the immune system and prevent it from attacking the implanted kidney.
The procedure itself was done at Northwestern Memorial Hospital in Chicago, using a live kidney donated by a neighbor of Waddell's, who camped out in Chicago during his recovery. Prior to surgery, Waddell underwent a conditioning treatment that consisted of low dose radiation and chemotherapy to weaken his own immune system and make room for the infusion of stem cells.
"The low intensity chemo and radiation conditioning regimen create just enough space for the donor stem cells to gain a foothold in the bone marrow and the donor's immune system takes over," says Dr. Joseph Levanthal, the transplant surgeon who performed the operation and director of kidney and pancreas transplantation at Northwestern University Feinberg School of Medicine. "That way the recipient develops an immune system that doesn't see the donor organ as foreign."
"As a surgeon, I saw what my patients had to go through—taking 25 pills a day, dying at an early age from heart disease, or having a 35% chance of dying every year on dialysis."
A week later, Waddell had the kidney transplant. The following day, he was infused with a complex cellular cocktail that included blood-forming stem cells derived from his donor's bone marrow mixed what are called tolerance inducing facilitator cells (FCs); these cells help the foreign stem cells get established in the recipient's bone marrow.
Over the course of the following year, he was slowly weaned off of antirejection medications—a precaution in case the procedure didn't work—and remarkably, hasn't needed them since. "I felt better than I had in decades because my kidneys [had been] degrading," recalls Waddell, now 54 and a CPA for a global beverage company. And what's even better is that this new approach offers hope for one of his sons who has also inherited the disorder.
Kidney transplants are the most frequent organ transplants in the world and more than 23,000 of these procedures were done in the United States in 2019, according to the United Network for Organ Sharing. Of this, about 7,000 operations are done annually using live organ donors; the remainder use organs from people who are deceased. Right now, this revolutionary new approach—as well as a similar strategy formulated by Stanford University scientists--is in the final phase of clinical trials. Ultimately, this research may pave the way towards realizing the holy grail of organ transplantation: preventing organ rejection by creating a tolerant state in which the recipient's immune system is compatible with the donor, which would eliminate the need for a lifetime of medications.
"As a surgeon, I saw what my patients had to go through—taking 25 pills a day, dying at an early age from heart disease, or having a 35% chance of dying every year on dialysis," says Dr. Suzanne Ildstad, a transplant surgeon and director of the Institute for Cellular Therapeutics at the University of Louisville, whose discovery of facilitator cells were the basis for this therapeutic platform. Ildstad, who has spent more than two decades searching for a better way, says, "This is something I have worked for my entire life."
The Louisville group uses a combination of chemo and radiation to replace the recipient's immune and blood forming cells with that of the donor. In contrast, the Stanford protocol involves harvesting the donor's blood stem cells and T-cells, which are the foot soldiers of the immune system that fight off infections and would normally orchestrate the rejection of the transplanted organ. Their transplant recipients undergo a milder form of "conditioning" that only radiates discrete parts of the body and selectively targets the recipient's T-cells, creating room for both sets of T-cells, a strategy these researchers believe has a better safety profile and less of a chance of rejection.
"We try to achieve immune tolerance by a true chimerism," says Dr. Samuel Strober, a professor of medicine for immunology and rheumatology at Stanford University and a leader of this research team. "The recipients immune system cells are maintained but mixed in the blood with that of the donor."
Studies suggest both approaches work. In a 2018 clinical trial conducted by Talaris Therapeutics, a Louisville-based biotech founded by Ildstad, 26 of 37 (70%) of the live donor kidney transplant recipients no longer need immunosuppressants. Last fall, Talaris began the final phase of clinical tests that will eventually encompass more than 120 such patients.
The Stanford group's cell-based immunotherapy, which is called MDR-101 and is sponsored by the South San Francisco biotech, Medeor Therapeutics, has had similar results in patients who received organs from live donors who were either well matched, such as one from siblings, meaning they were immunologically identical, or partially matched; Talaris uses unrelated donors where there is only a partial match.
In their 2020 clinical trial of 51 patients, 29 were fully matched and 22 were a partial match; 22 of the fully matched recipients didn't need antirejection drugs and ten of the partial matches were able to stop taking some of these medications without rejection. "With our fully matched, roughly 80% have been completely off drugs up to 14 years later," says Strober, "and reducing the number of drugs from three to one [in the partial matches] means you have far fewer side effects. The goal is to get them off of all drugs."
But these protocols are limited to a small number of patients—living donor kidney recipients. As a consequence, both teams are experimenting with ways to broaden their approach so they can use cadaver organs from deceased donors, with human tests planned in the coming year. Here's how that would work: after the other organs are removed from a deceased donor, stem cells are harvested from the donor's vertebrae in the spinal column and then frozen for storage.
"We do the transplant and give the patient a chance to recover and maintain them on drugs," says Ildstad. "Then we do the tolerance conditioning at a later stage."
If this strategy is successful, it would be a genuine game changer, and open the door to using these protocols for transplanting other cadaver organs, including the heart, lungs and liver. While the overall procedure is complex and costly, in the long run it's less expensive than repeated transplant surgeries, the cost of medications and hospitalizations for complications caused by the drugs, or thrice weekly dialysis treatments, says Ildstad.
And she adds, you can't put a price tag on the vast improvement in quality of life.
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."
Probiotics seem to be everywhere these days. They are marketed for numerous health issues, from irritable bowel syndrome and vaginal yeast infections to life-threatening disorders like the bacterial infection Clostridium difficile.
The new probiotic drink is made of genetically engineered bacteria meant to help people feel better the day after drinking.
While the probiotic gummies that you'll find in supermarkets may not do much for you, good clinical evidence does support the C. difficile treatment, known as a fecal transplant, despite a recent setback, and there are always new probiotic regimens entering the scene. One emerging such treatment targets the hangover.
The Lowdown
You read that right – although "hangover" is a loaded term, according to ZBiotics, the company that's developing the product. The popular understanding of a hangover implies a collection of symptoms like a headache and fatigue, many of which result simply from dehydration and low-quality sleep. But those aren't the problems that the new product, a genetically engineered form of a common bacterial species, was developed to confront.
"Dehydration and poor sleep have actually always been pretty simple to deal with by having a good breakfast and some caffeine," notes ZBiotics founder and microbiologist Zack Abbott. Instead, the product targets acetaldehyde, a chemical that accumulates in the body if more than small amounts of alcohol are consumed.
Normally, body cells produce an enzyme that converts acetaldehyde into harmless acetic acid. But the enzyme becomes overwhelmed if you drink more than a little alcohol, or if you have a certain genetic deficiency.
A new probiotic drink aims to neutralize a chemical that builds up in the body after drinking alcohol.
(Zbiotics)
"I started ZBiotics with the hypothesis that if we used edible probiotic bacteria to make enzymes, and chose applications in which the enzymes these microbes make would be useful directly in the gut after you eat them, we could create all sorts of beneficial products," says Abbott. "I started with alcohol with the idea that we can augment the body's natural ability to digest its nasty byproduct, acetaldehyde, helping people feel better the day after drinking."
Next Steps
Based on the premise that the engineered bacteria augments a natural body function, ZBiotics had the product "sampled by thousands of beta-testers," including ZBiotics personnel, with "almost unanimously positive feedback," says Abbott.
"We are working on future scientifically controlled testing for publication."
ZBiotics is to set to launch on the market next week as a probiotic supplement, a category that does not require FDA approval. But some observers are troubled over whether the new product is attempting to serve a medical function without going through the standard drug testing process.
"I am skeptical of any new alternative product that is not FDA approved, has not undergone rigorous double-blind placebo control testing and adverse effects evaluation, and cites anecdotes as evidence of its efficacy," warns Heather Berlin, a cognitive neuroscientist and assistant professor of psychiatry at Icahn School of Medicine at Mount Sinai, in New York.
Abbott acknowledges that his product still needs to undergo rigorous study. "We are working on future scientifically controlled testing for publication," he says, noting that the company was "founded and [is] run by people with backgrounds in academic research."
Open Questions
Moving beyond the need for proper testing, Berlin has an additional concern: will a "hangover"-blocking substance cause people to drink more alcohol, or mask important physiological sensations like thirst?
"If that negative feeling is obscured, they may not [rehydrate], which can cause numerous adverse effects," Berlin says.
As for excessive drinking, there is a treatment on the market that does the opposite of Zbiotics. Disulfiram, commonly given to alcohol abusers, inhibits the very enzyme that ZBiotics supplements, causing acetaldehyde to accumulate especially fast. This makes drinking a pretty miserable experience.
But Abbott says his product would not interfere with disulfiram.
"[Zbiotics] is about enjoying the special moments in life where alcohol happens to be involved, but isn't the main focus."
"Disulfiram globally inhibits the enzyme throughout the entire body, including the liver, creating a massive amount of acetaldehyde at once, making the person ill immediately and forcing them to stop drinking right away," Abbott explains, whereas his product exerts its effects in the gut, and is really only helpful the next day. Thus, timing is everything; the probiotic would not change the experience at the moment of drinking.
"ZBiotics isn't about going out and ripping shots all night," Abbott says. "It's about enjoying the special moments in life where alcohol happens to be involved, but isn't the main focus. Weddings, celebrations, weekends with friends. And wanting to do that enjoyably while being safe and responsible at the same time."