A New Stem Cell Therapy Provides Hope to Patients with Blood Cancer
Stacey Khoury felt more fatigued and out of breath than she was used to from just walking up the steps to her job in retail jewelry sales in Nashville, Tennessee. By the time she got home, she was more exhausted than usual, too.
"I just thought I was working too hard and needed more exercise," recalls the native Nashvillian about those days in December 2010. "All of the usual excuses you make when you're not feeling 100%."
As a professional gemologist, being hospitalized during peak holiday sales season wasn't particularly convenient. There was no way around it though when her primary care physician advised Khoury to see a blood disorder oncologist because of her disturbing blood count numbers. As part of a routine medical exam, a complete blood count screens for a variety of diseases and conditions that affect blood cells, such as anemia, infection, inflammation, bleeding disorders and cancer.
"If approved, it will allow more patients to potentially receive a transplant than would have gotten one before."
While she was in the hospital, a bone marrow biopsy revealed that Khoury had acute myeloid leukemia, or AML, a high-risk blood cancer. After Khoury completed an intense first round of chemotherapy, her oncologist recommended a bone marrow transplant. The potentially curative treatment for blood-cancer patients requires them to first receive a high dose of chemotherapy. Next, an infusion of stem cells from a healthy donor's bone marrow helps form new blood cells to fight off the cancer long-term.
Each year, approximately 8,000 patients in the U.S. with AML and other blood cancers receive a bone marrow transplant from a donor, according to the Center for International Blood and Marrow Transplant Research. But Khoury wasn't so lucky. She ended up being among the estimated 40% of patients eligible for bone marrow transplants who don't receive one, usually because there's no matched donor available.
Khoury's oncologist told her about another option. She could enter a clinical trial for an investigational cell therapy called omidubicel, which is being developed by Israeli biotech company Gamida Cell. The company's cell therapy, which is still experimental, could up a new avenue of treatment for cancer patients who can't get a bone marrow transplant.
Omidubicel consists of stem cells from cord blood that have been expanded using Gamida's technology to ensure there are enough cells for a therapeutic dose. The company's technology allows the immature cord blood cells to multiply quickly in the lab. Like a bone marrow transplant, the goal of the therapy is to make sure the donor cells make their way to the bone marrow and begin producing healthy new cells — a process called engraftment.
"If approved, it will allow more patients to potentially receive a transplant than would have gotten one before, so there's something very novel and exciting about that," says Ronit Simantov, Gamida Cell's chief medical officer.
Khoury and her husband Rick packed up their car and headed to the closest trial site, the Duke University School of Medicine, roughly 500 miles away. There they met with Mitchell Horowitz, a stem cell transplant specialist at Duke and principal investigator for Gamida's omidubicel study in the U.S.
He told Khoury she was a perfect candidate for the trial, and she enrolled immediately. "When you have one of two decisions, and it's either do this or you're probably not going to be around, it was a pretty easy decision to make, and I am truly thankful for that," she says.
Khoury's treatment started at the end of March 2011, and she was home by July 4 that year. She say the therapy "worked the way the doctors wanted it to work." Khoury's blood counts were rising quicker than the people who had bone marrow matches, and she was discharged from Duke earlier than other patients were.
By expanding the number of cord blood cells — which are typically too few to treat an adult — omidubicel allows doctors to use cord blood for patients who require a transplant but don't have a donor match for bone marrow.
Patients receiving omidubicel first get a blood test to determine their human leukocyte antigen, or HLA, type. This protein is found on most cells in the body and is an important regulator of the immune system. HLA typing is used to match patients to bone marrow and cord blood donors, but cord blood doesn't require as close of a match.
Like bone marrow transplants, one potential complication of omidubicel is graft-versus-host disease, when the donated bone marrow or stem cells register the recipient's body as foreign and attack the body. Depending on the severity of the response, according to the Mayo Clinic, treatment includes medication to suppress the immune system, such as steroids. In clinical trials, the occurrence of graft-versus-host disease with omidubicel was comparable with traditional bone marrow transplants.
"Transplant doctors are working on improving that," Simantov says. "A number of new therapies that specifically address graft-versus-host disease will be making some headway in the coming months and years."
Gamida released the results of the Phase 3 study in February and continues to follow Khoury and the other study patients for their long-term outcomes. The large randomized trial evaluated the safety and efficacy of omidubicel compared to standard umbilical cord blood transplants in patients with blood cancer who didn't have a suitable bone marrow donor. Around 120 patients aged 12 to 65 across the U.S., Europe and Asia were included in the trial. The study found that omidubicel resulted in faster recovery, fewer bacterial and viral infections and fewer days in the hospital.
The company plans to seek FDA approval this year. Simantov anticipates the therapy will receive FDA approval by 2022.
"Opening up cord blood transplants is very important, especially for people of diverse ethnic backgrounds," says oncologist Gary Schiller, principal investigator at the David Geffen School of Medicine at UCLA for Gamida Cell's mid- and late-stage trials. "This expansion technology makes a big difference because it makes cord blood an available option for those who do not have another donor source."
As for Khoury, who proudly celebrated the anniversary of her first transplant in April—she remains cancer free and continues to work full-time as a gemologist. When she has a little free time, she enjoys gardening, sewing, or maybe traveling to national parks like Yellowstone or the Grand Canyon with her husband Rick.
In recent years, researchers of Alzheimer’s have made progress in figuring out the complex factors that lead to the disease. Yet, the root cause, or causes, of Alzheimer’s are still pretty much a mystery.
In fact, many people get Alzheimer’s even though they lack the gene variant we know can play a role in the disease. This is a critical knowledge gap for research to address because the vast majority of Alzheimer’s patients don’t have this variant.
A new study provides key insights into what’s causing the disease. The research, published in Nature Communications, points to a breakdown over time in the brain’s system for clearing waste, an issue that seems to happen in some people as they get older.
Michael Glickman, a biologist at Technion – Israel Institute of Technology, helped lead this research. I asked him to tell me about his approach to studying how this breakdown occurs in the brain, and how he tested a treatment that has potential to fix the problem at its earliest stages.
Dr. Michael Glickman is internationally renowned for his research on the ubiquitin-proteasome system (UPS), the brain's system for clearing the waste that is involved in diseases such as Huntington's, Alzheimer's, and Parkinson's. He is the head of the Lab for Protein Characterization in the Faculty of Biology at the Technion – Israel Institute of Technology. In the lab, Michael and his team focus on protein recycling and the ubiquitin-proteasome system, which protects against serious diseases like Alzheimer’s, Parkinson’s, cystic fibrosis, and diabetes. After earning his PhD at the University of California at Berkeley in 1994, Michael joined the Technion as a Senior Lecturer in 1998 and has served as a full professor since 2009.
Dr. Michael Glickman
When Drew Weissman received a call from Katalin Karikó in the early morning hours this past Monday, he assumed his longtime research partner was calling to share a nascent, nagging idea. Weissman, a professor of medicine at the Perelman School of Medicine at the University of Pennsylvania, and Karikó, a professor at Szeged University and an adjunct professor at UPenn, both struggle with sleep disturbances. Thus, middle-of-the-night discourses between the two, often over email, has been a staple of their friendship. But this time, Karikó had something more pressing and exciting to share: They had won the 2023 Nobel Prize in Physiology or Medicine.
The work for which they garnered the illustrious award and its accompanying $1,000,000 cash windfall was completed about two decades ago, wrought through long hours in the lab over many arduous years. But humanity collectively benefited from its life-saving outcome three years ago, when both Moderna and Pfizer/BioNTech’s mRNA vaccines against COVID were found to be safe and highly effective at preventing severe disease. Billions of doses have since been given out to protect humans from the upstart viral scourge.
“I thought of going somewhere else, or doing something else,” said Katalin Karikó. “I also thought maybe I’m not good enough, not smart enough. I tried to imagine: Everything is here, and I just have to do better experiments.”
Unlocking the power of mRNA
Weissman and Karikó unlocked mRNA vaccines for the world back in the early 2000s when they made a key breakthrough. Messenger RNA molecules are essentially instructions for cells’ ribosomes to make specific proteins, so in the 1980s and 1990s, researchers started wondering if sneaking mRNA into the body could trigger cells to manufacture antibodies, enzymes, or growth agents for protecting against infection, treating disease, or repairing tissues. But there was a big problem: injecting this synthetic mRNA triggered a dangerous, inflammatory immune response resulting in the mRNA’s destruction.
While most other researchers chose not to tackle this perplexing problem to instead pursue more lucrative and publishable exploits, Karikó stuck with it. The choice sent her academic career into depressing doldrums. Nobody would fund her work, publications dried up, and after six years as an assistant professor at the University of Pennsylvania, Karikó got demoted. She was going backward.
“I thought of going somewhere else, or doing something else,” Karikó told Stat in 2020. “I also thought maybe I’m not good enough, not smart enough. I tried to imagine: Everything is here, and I just have to do better experiments.”
A tale of tenacity
Collaborating with Drew Weissman, a new professor at the University of Pennsylvania, in the late 1990s helped provide Karikó with the tenacity to continue. Weissman nurtured a goal of developing a vaccine against HIV-1, and saw mRNA as a potential way to do it.
“For the 20 years that we’ve worked together before anybody knew what RNA is, or cared, it was the two of us literally side by side at a bench working together,” Weissman said in an interview with Adam Smith of the Nobel Foundation.
In 2005, the duo made their 2023 Nobel Prize-winning breakthrough, detailing it in a relatively small journal, Immunity. (Their paper was rejected by larger journals, including Science and Nature.) They figured out that chemically modifying the nucleoside bases that make up mRNA allowed the molecule to slip past the body’s immune defenses. Karikó and Weissman followed up that finding by creating mRNA that’s more efficiently translated within cells, greatly boosting protein production. In 2020, scientists at Moderna and BioNTech (where Karikó worked from 2013 to 2022) rushed to craft vaccines against COVID, putting their methods to life-saving use.
The future of vaccines
Buoyed by the resounding success of mRNA vaccines, scientists are now hurriedly researching ways to use mRNA medicine against other infectious diseases, cancer, and genetic disorders. The now ubiquitous efforts stand in stark contrast to Karikó and Weissman’s previously unheralded struggles years ago as they doggedly worked to realize a shared dream that so many others shied away from. Katalin Karikó and Drew Weissman were brave enough to walk a scientific path that very well could have ended in a dead end, and for that, they absolutely deserve their 2023 Nobel Prize.