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.
New Tech Can Predict Breast Cancer Years in Advance
Every two minutes, a woman is diagnosed with breast cancer. The question is, can those at high risk be identified early enough to survive?
New AI software has predicted risk equally well in both white and black women for the first time.
The current standard practice in medicine is not exactly precise. It relies on age, family history of cancer, and breast density, among other factors, to determine risk. But these factors do not always tell the whole story, leaving many women to slip through the cracks. In addition, a racial gap persists in breast cancer treatment and survival. African-American women are 42 percent more likely to die from the disease despite relatively equal rates of diagnosis.
But now those grim statistics could be changing. A team of researchers from MIT's Computer Science and Artificial Intelligence Laboratory have developed a deep learning model that can more accurately predict a patient's breast cancer risk compared to established clinical guidelines – and it has predicted risk equally well in both white and black women for the first time.
The Lowdown
Study results published in Radiology described how the AI software read mammogram images from more than 60,000 patients at Massachusetts General Hospital to identify subtle differences in breast tissue that pointed to potential risk factors, even in their earliest stages. The team accessed the patients' actual diagnoses and determined that the AI model was able to correctly place 31 percent of all cancer patients in the highest-risk category of developing breast cancer within five years of the examination, compared to just 18 percent for existing models.
"Each image has hundreds of thousands of pixels identifying something that may not necessarily be detected by the human eye," said MIT professor Regina Barzilay, one of the study's lead authors. "We all have limited visual capacities so it seems some machines trained on hundreds of thousands of images with a known outcome can capture correlations the human eye might not notice."
Barzilay, a breast cancer survivor herself, had abnormal tissue patterns on mammograms in 2012 and 2013, but wasn't diagnosed until after a 2014 image reading, illustrating the limitations of human processing alone.
MIT professor Regina Barzilay, a lead author on the new study and a breast cancer survivor herself.
(Courtesy MIT)
Next up: The MIT team is looking at training the model to detect other cancers and health risks. Barzilay recalls how a cardiologist told her during a conference that women with heart diseases had a different pattern of calcification on their mammograms, demonstrating how already existing images can be used to extract other pieces of information about a person's health status.
Integration of the AI model in standard care could help doctors better tailor screening and prevention programs based on actual instead of perceived risk. Patients who might register as higher risk by current guidelines could be identified as lower risk, helping resolve conflicting opinions about how early and how often women should receive mammograms.
Open Questions: While the results were promising, it's unknown how well the model will work on a larger scale, as the study looked at data from just one institution and used mammograms supplied by just one hospital. Some risk factor information was also unavailable for certain patients during the study, leaving researchers unable to fully compare the AI model's performance to that of the traditional standard.
One incentive to wider implementation and study, however, is the bonus that no new hardware is required to use the AI model. With other institutions now showing interest, this software could lead to earlier routine detection and treatment of breast cancer — resulting in more lives saved.
Sarah Mancoll was 22 years old when she noticed a bald spot on the back of her head. A dermatologist confirmed that it was alopecia aerata, an autoimmune disorder that causes hair loss.
Of 213 new drugs approved from 2003 to 2012, only five percent included any data from pregnant women.
She successfully treated the condition with corticosteroid shots for nearly 10 years. Then Mancoll and her husband began thinking about starting a family. Would the shots be safe for her while pregnant? For the fetus? What about breastfeeding?
Mancoll consulted her primary care physician, her dermatologist, even a pediatrician. Without clinical data, no one could give her a definitive answer, so she stopped treatment to be "on the safe side." By the time her son was born, she'd lost at least half her hair. She returned to her Washington, D.C., public policy job two months later entirely bald—and without either eyebrows or eyelashes.
After having two more children in quick succession, Mancoll recently resumed the shots but didn't forget her experience. Today, she is an advocate for including more pregnant and lactating women in clinical studies so they can have more information about therapies than she did.
"I live a very privileged life, and I'll do just fine with or without hair, but it's not just about me," Mancoll said. "It's about a huge population of women who are being disenfranchised…They're invisible."
About 4 million women give birth each year in the United States, and many face medical conditions, from hypertension and diabetes to psychiatric disorders. A 2011 study showed that most women reported taking at least one medication while pregnant between 1976 and 2008. But for decades, pregnant and lactating women have been largely excluded from clinical drug studies that rigorously test medications for safety and effectiveness.
An estimated 98 percent of government-approved drug treatments between 2000 and 2010 had insufficient data to determine risk to the fetus, and close to 75 percent had no human pregnancy data at all. All told, of 213 new pharmaceuticals approved from 2003 to 2012, only five percent included any data from pregnant women.
But recent developments suggest that could be changing. Amid widespread concerns about increased maternal mortality rates, women's health advocates, physicians, and researchers are sensing and encouraging a cultural shift toward protecting women through responsible research instead of from research.
"The question is not whether to do research with pregnant women, but how," Anne Drapkin Lyerly, professor and associate director of the Center for Bioethics at the University of North Carolina at Chapel Hill, wrote last year in an op-ed. "These advances are essential. It is well past time—and it is morally imperative—for research to benefit pregnant women."
"In excluding pregnant women from drug trials to protect them from experimentation, we subject them to uncontrolled experimentation."
To that end, the American College of Obstetricians and Gynecologists' Committee on Ethics acknowledged that research trials need to be better designed so they don't "inappropriately constrain the reproductive choices of study participants or unnecessarily exclude pregnant women." A federal task force also called for significantly expanded research and the removal of regulatory barriers that make it difficult for pregnant and lactating women to participate in research.
Several months ago, a government change to a regulation known as the Common Rule took effect, removing pregnant women as a "vulnerable population" in need of special protections -- a designation that had made it more difficult to enroll them in clinical drug studies. And just last week, the U.S. Food and Drug Administration (FDA) issued new draft guidances for industry on when and how to include pregnant and lactating women in clinical trials.
Inclusion is better than the absence of data on their treatment, said Catherine Spong, former chair of the federal task force.
"It's a paradox," said Spong, professor of obstetrics and gynecology and chief of maternal fetal medicine at University of Texas Southwestern Medical Center. "There is a desire to protect women and fetuses from harm, which is translated to a reluctance to include them in research. By excluding them, the evidence for their care is limited."
Jacqueline Wolf, a professor of the history of medicine at Ohio University, agreed.
"In excluding pregnant women from drug trials to protect them from experimentation, we subject them to uncontrolled experimentation," she said. "We give them the medication without doing any research, and that's dangerous."
Women, of course, don't stop getting sick or having chronic medical conditions just because they are pregnant or breastfeeding, and conditions during pregnancy can affect a baby's health later in life. Evidence-based data is important for other reasons, too.
Pregnancy can dramatically change a woman's physiology, affecting how drugs act on her body and how her body acts or reacts to drugs. For instance, pregnant bodies can more quickly clear out medications such as glyburide, used during diabetes in pregnancy to stabilize high blood-sugar levels, which can be toxic to the fetus and harmful to women. That means a regular dose of the drug may not be enough to control blood sugar and prevent poor outcomes.
Pregnant patients also may be reluctant to take needed drugs for underlying conditions (and doctors may be hesitant to prescribe them), which in turn can cause more harm to the woman and fetus than had they been treated. For example, women who have severe asthma attacks while pregnant are at a higher risk of having low-birthweight babies, and pregnant women with uncontrolled diabetes in early pregnancy have more than four times the risk of birth defects.
Current clinical trials involving pregnant women are assessing treatments for obstructive sleep apnea, postpartum hemorrhage, lupus, and diabetes.
For Kate O'Brien, taking medication during her pregnancy was a matter of life and death. A freelance video producer who lives in New Jersey, O'Brien was diagnosed with tuberculosis in 2015 after she became pregnant with her second child, a boy. Even as she signed hospital consent forms, she had no idea if the treatment would harm him.
"It's a really awful experience," said O'Brien, who now is active with We are TB, an advocacy and support network. "All they had to tell me about the medication was just that women have been taking it for a really long time all over the world. That was the best they could do."
More and more doctors, researchers and women's health organizations and advocates are calling that unacceptable.
By indicating that filling current knowledge gaps is "a critical public health need," the FDA is signaling its support for advancing research with pregnant women, said Lyerly, also co-founder of the Second Wave Initiative, which promotes fair representation of the health interests of pregnant women in biomedical research and policies. "It's a very important shift."
Research with pregnant women can be done ethically, Lyerly said, whether by systematically collecting data from those already taking medications or enrolling pregnant women in studies of drugs or vaccines in development.
Current clinical trials involving pregnant women are assessing treatments for obstructive sleep apnea, postpartum hemorrhage, lupus, and diabetes. Notable trials in development target malaria and HIV prevention in pregnancy.
"It clearly is doable to do this research, and test trials are important to provide evidence for treatment," Spong said. "If we don't have that evidence, we aren't making the best educated decisions for women."