New therapy may improve stem cell transplants for blood cancers
In 2018, Robyn was diagnosed with myelofibrosis, a blood cancer causing chronic inflammation and scarring. As a research scientist by training, she knew she had limited options. A stem cell transplant is a terminally ill patient's best chance for survival against blood cancers, including leukaemia. It works by destroying a patient's cancer cells and replacing them with healthy cells from a donor.
However, there is a huge risk of Graft vs Host disease (GVHD), which affects around 30-40% of recipients. Patients receive billions of cells in a stem cell transplant but only a fraction are beneficial. The rest can attack healthy tissue leading to GVHD. It affects the skin, gut and lungs and can be truly debilitating.
Currently, steroids are used to try and prevent GVHD, but they have many side effects and are effective in only 50% of cases. “I spoke with my doctors and reached out to patients managing GVHD,” says Robyn, who prefers not to use her last name for privacy reasons. “My concerns really escalated for what I might face post-transplant.”
Then she heard about a new highly precise cell therapy developed by a company called Orca Bio, which gives patients more beneficial cells and fewer cells that cause GVHD. She decided to take part in their phase 2 trial.
How It Works
In stem cell transplants, patients receive immune cells and stem cells. The donor immune cells or T cells attack and kill malignant cells. This is the graft vs leukaemia effect (GVL). The stem cells generate new healthy cells.
Unfortunately, T cells can also cause GVHD, but a rare subset of T cells, called T regulatory cells, can actually prevent GVHD.
Orca’s cell sorting technology distinguishes T regulatory cells from stem cells and conventional T cells on a large scale. It’s this cell sorting technology which has enabled them to create their new cell therapy, called Orca T. It contains a precise combination of stem cells and immune cells with more T regulatory cells and fewer conventional T cells than in a typical stem cell transplant.
“Ivan Dimov’s idea was to spread out the cells, keep them stationary and then use laser scanning to sort the cells,” explains Nate Fernhoff, co-founder of Orca Bio. “The beauty here is that lasers don't care how quickly you move them.”
Over the past 40 years, scientists have been trying to create stem cell grafts that contain the beneficial cells whilst removing the cells that cause GVHD. What makes it even harder is that most transplant centers aren’t able to manipulate grafts to create a precise combination of cells.
Innovative Cell Sorting
Ivan Dimov, Jeroen Bekaert and Nate Fernhoff came up with the idea behind Orca as postdocs at Stanford, working with cell pioneer Irving Weissman. They recognised the need for a more effective cell sorting technology. In a small study at Stanford, Professor Robert Negrin had discovered a combination of T cells, T regulatory cells and stem cells which prevented GVHD but retained the beneficial graft vs leukaemia effect (GVL). However, manufacturing was problematic. Conventional cell sorting is extremely slow and specific. Negrin was only able to make seven highly precise products, for seven patients, in a year. Annual worldwide cases of blood cancer number over 1.2 million.
“We started Orca with this idea: how do we use manufacturing solutions to impact cell therapies,” co-founder Fernhoff reveals. In conventional cell sorting, cells move past a stationary laser which analyses each cell. But cells can only be moved so quickly. At a certain point they start to experience stress and break down. This makes it very difficult to sort the 100 billion cells from a donor in a stem cell transplant.
“Ivan Dimov’s idea was to spread out the cells, keep them stationary and then use laser scanning to sort the cells,” Fernhoff explains. “The beauty here is that lasers don't care how quickly you move them.” They developed this technology and called it Orca Sort. It enabled Orca to make up to six products per week in the first year of manufacturing.
Every product Orca makes is for one patient. The donor is uniquely matched to the patient. They have to carry out the cell sorting procedure each time. Everything also has to be done extremely quickly. They infuse fresh living cells from the donor's vein to the patient's within 72 hours.
“We’ve treated almost 200 patients in all the Orca trials, and you can't do that if you don't fix the manufacturing process,” Fernhoff says. “We're working on what we think is an incredibly promising drug, but it's all been enabled by figuring out how to make a high precision cell therapy at scale.”
Clinical Trials
Orca revealed the results of their phase 1b and phase 2 trials at the end of last year. In their phase 2 trial only 3% of the 29 patients treated with Orca T cell therapy developed chronic GVHD in the first year after treatment. Comparatively, 43% of the 95 patients given a conventional stem cell transplant in a contemporary Stanford trial developed chronic GVHD. Of the 109 patients tested in phase 1b and phase 2 trials, 74% using Orca T didn't relapse or develop any form of GVHD compared to 34% in the control trial.
“Until a randomised study is done, we can make no assumption about the relative efficacy of this approach," says Jeff Szer, professor of haematology at the Royal Melbourne Hospital. "But the holy grail of separating GVHD and GVL is still there and this is a step towards realising that dream.”
Stan Riddell, an immunology professor, at Fred Hutchinson Cancer Centre, believes Orca T is highly promising. “Orca has advanced cell selection processes with innovative methodology and can engineer grafts with greater precision to add cell subsets that may further contribute to beneficial outcomes,” he says. “Their results in phase 1 and phase 2 studies are very exciting and offer the potential of providing a new standard of care for stem cell transplant.”
However, though it is an “intriguing step,” there’s a need for further testing, according to Jeff Szer, a professor of haematology at the Peter MacCallum Cancer Centre at the Royal Melbourne Hospital.
“The numbers tested were tiny and comparing the outcomes to anything from a phase 1/2 setting is risky,” says Szer. “Until a randomised study is done, we can make no assumption about the relative efficacy of this approach. But the holy grail of separating GVHD and GVL is still there and this is a step towards realising that dream.”
The Future
The team is soon starting Phase 3 trials for Orca T. Its previous success has led them to develop Orca Q, a cell therapy for patients who can't find an exact donor match. Transplants for patients who are only a half-match or mismatched are not widely used because there is a greater risk of GVHD. Orca Q has the potential to control GVHD even more and improve access to transplants for many patients.
Fernhoff hopes they’ll be able to help people not just with blood cancers but also with other blood and immune disorders. If a patient has a debilitating disease which isn't life threatening, the risk of GVHD outweighs the potential benefits of a stem cell transplant. The Orca products could take away that risk.
Meanwhile, Robyn has no regrets about participating in the Phase 2 trial. “It was a serious decision to make but I'm forever grateful that I did,” she says. “I have resumed a quality of life aligned with how I felt pre-transplant. I have not had a single issue with GVHD.”
“I want to be able to get one of these products to every patient who could benefit from it,” Fernhoff says. “It's really exciting to think about how Orca's products could be applied to all sorts of autoimmune disorders.”
Scientists turn pee into power in Uganda
At the edge of a dirt road flanked by trees and green mountains outside the town of Kisoro, Uganda, sits the concrete building that houses Sesame Girls School, where girls aged 11 to 19 can live, learn and, at least for a while, safely use a toilet. In many developing regions, toileting at night is especially dangerous for children. Without electrical power for lighting, kids may fall into the deep pits of the latrines through broken or unsteady floorboards. Girls are sometimes assaulted by men who hide in the dark.
For the Sesame School girls, though, bright LED lights, connected to tiny gadgets, chased the fears away. They got to use new, clean toilets lit by the power of their own pee. Some girls even used the light provided by the latrines to study.
Urine, whether animal or human, is more than waste. It’s a cheap and abundant resource. Each day across the globe, 8.1 billion humans make 4 billion gallons of pee. Cows, pigs, deer, elephants and other animals add more. By spending money to get rid of it, we waste a renewable resource that can serve more than one purpose. Microorganisms that feed on nutrients in urine can be used in a microbial fuel cell that generates electricity – or "pee power," as the Sesame girls called it.
Plus, urine contains water, phosphorus, potassium and nitrogen, the key ingredients plants need to grow and survive. Human urine could replace about 25 percent of current nitrogen and phosphorous fertilizers worldwide and could save water for gardens and crops. The average U.S. resident flushes a toilet bowl containing only pee and paper about six to seven times a day, which adds up to about 3,500 gallons of water down per year. Plus cows in the U.S. produce 231 gallons of the stuff each year.
Pee power
A conventional fuel cell uses chemical reactions to produce energy, as electrons move from one electrode to another to power a lightbulb or phone. Ioannis Ieropoulos, a professor and chair of Environmental Engineering at the University of Southampton in England, realized the same type of reaction could be used to make a fuel from microbes in pee.
Bacterial species like Shewanella oneidensis and Pseudomonas aeruginosa can consume carbon and other nutrients in urine and pop out electrons as a result of their digestion. In a microbial fuel cell, one electrode is covered in microbes, immersed in urine and kept away from oxygen. Another electrode is in contact with oxygen. When the microbes feed on nutrients, they produce the electrons that flow through the circuit from one electrod to another to combine with oxygen on the other side. As long as the microbes have fresh pee to chomp on, electrons keep flowing. And after the microbes are done with the pee, it can be used as fertilizer.
These microbes are easily found in wastewater treatment plants, ponds, lakes, rivers or soil. Keeping them alive is the easy part, says Ieropoulos. Once the cells start producing stable power, his group sequences the microbes and keeps using them.
Like many promising technologies, scaling these devices for mass consumption won’t be easy, says Kevin Orner, a civil engineering professor at West Virginia University. But it’s moving in the right direction. Ieropoulos’s device has shrunk from the size of about three packs of cards to a large glue stick. It looks and works much like a AAA battery and produce about the same power. By itself, the device can barely power a light bulb, but when stacked together, they can do much more—just like photovoltaic cells in solar panels. His lab has produced 1760 fuel cells stacked together, and with manufacturing support, there’s no theoretical ceiling, he says.
Although pure urine produces the most power, Ieropoulos’s devices also work with the mixed liquids of the wastewater treatment plants, so they can be retrofit into urban wastewater utilities.
This image shows how the pee-powered system works. Pee feeds bacteria in the stack of fuel cells (1), which give off electrons (2) stored in parallel cylindrical cells (3). These cells are connected to a voltage regulator (4), which smooths out the electrical signal to ensure consistent power to the LED strips lighting the toilet.
Courtesy Ioannis Ieropoulos
Key to the long-term success of any urine reclamation effort, says Orner, is avoiding what he calls “parachute engineering”—when well-meaning scientists solve a problem with novel tech and then abandon it. “The way around that is to have either the need come from the community or to have an organization in a community that is committed to seeing a project operate and maintained,” he says.
Success with urine reclamation also depends on the economy. “If energy prices are low, it may not make sense to recover energy,” says Orner. “But right now, fertilizer prices worldwide are generally pretty high, so it may make sense to recover fertilizer and nutrients.” There are obstacles, too, such as few incentives for builders to incorporate urine recycling into new construction. And any hiccups like leaks or waste seepage will cost builders money and reputation. Right now, Orner says, the risks are just too high.
Despite the challenges, Ieropoulos envisions a future in which urine is passed through microbial fuel cells at wastewater treatment plants, retrofitted septic tanks, and building basements, and is then delivered to businesses to use as agricultural fertilizers. Although pure urine produces the most power, Ieropoulos’s devices also work with the mixed liquids of the wastewater treatment plants, so they can be retrofitted into urban wastewater utilities where they can make electricity from the effluent. And unlike solar cells, which are a common target of theft in some areas, nobody wants to steal a bunch of pee.
When Ieropoulos’s team returned to wrap up their pilot project 18 months later, the school’s director begged them to leave the fuel cells in place—because they made a major difference in students’ lives. “We replaced it with a substantial photovoltaic panel,” says Ieropoulos, They couldn’t leave the units forever, he explained, because of intellectual property reasons—their funders worried about theft of both the technology and the idea. But the photovoltaic replacement could be stolen, too, leaving the girls in the dark.
The story repeated itself at another school, in Nairobi, Kenya, as well as in an informal settlement in Durban, South Africa. Each time, Ieropoulos vowed to return. Though the pandemic has delayed his promise, he is resolute about continuing his work—it is a moral and legal obligation. “We've made a commitment to ourselves and to the pupils,” he says. “That's why we need to go back.”
Urine as fertilizer
Modern day industrial systems perpetuate the broken cycle of nutrients. When plants grow, they use up nutrients the soil. We eat the plans and excrete some of the nutrients we pass them into rivers and oceans. As a result, farmers must keep fertilizing the fields while our waste keeps fertilizing the waterways, where the algae, overfertilized with nitrogen, phosphorous and other nutrients grows out of control, sucking up oxygen that other marine species need to live. Few global communities remain untouched by the related challenges this broken chain create: insufficient clean water, food, and energy, and too much human and animal waste.
The Rich Earth Institute in Vermont runs a community-wide urine nutrient recovery program, which collects urine from homes and businesses, transports it for processing, and then supplies it as fertilizer to local farms.
One solution to this broken cycle is reclaiming urine and returning it back to the land. The Rich Earth Institute in Vermont is one of several organizations around the world working to divert and save urine for agricultural use. “The urine produced by an adult in one day contains enough fertilizer to grow all the wheat in one loaf of bread,” states their website.
Notably, while urine is not entirely sterile, it tends to harbor fewer pathogens than feces. That’s largely because urine has less organic matter and therefore less food for pathogens to feed on, but also because the urinary tract and the bladder have built-in antimicrobial defenses that kill many germs. In fact, the Rich Earth Institute says it’s safe to put your own urine onto crops grown for home consumption. Nonetheless, you’ll want to dilute it first because pee usually has too much nitrogen and can cause “fertilizer burn” if applied straight without dilution. Other projects to turn urine into fertilizer are in progress in Niger, South Africa, Kenya, Ethiopia, Sweden, Switzerland, The Netherlands, Australia, and France.
Eleven years ago, the Institute started a program that collects urine from homes and businesses, transports it for processing, and then supplies it as fertilizer to local farms. By 2021, the program included 180 donors producing over 12,000 gallons of urine each year. This urine is helping to fertilize hay fields at four partnering farms. Orner, the West Virginia professor, sees it as a success story. “They've shown how you can do this right--implementing it at a community level scale."
The Friday Five covers five stories in research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
Here are the promising studies covered in this week's Friday Five, featuring interviews with Dr. David Spiegel, associate chair of psychiatry and behavioral sciences at Stanford, and Dr. Filip Swirski, professor of medicine and cardiology at the Icahn School of Medicine at Mount Sinai.
Listen on Apple | Listen on Spotify | Listen on Stitcher | Listen on Amazon | Listen on Google
Here are the promising studies covered in this week's Friday Five, featuring interviews with Dr. David Spiegel, associate chair of psychiatry and behavioral sciences at Stanford, and Dr. Filip Swirski, professor of medicine and cardiology at the Icahn School of Medicine at Mount Sinai.
- Breathing this way cuts down on anxiety*
- Could your fasting regimen make you sick?
- This type of job makes men more virile
- 3D printed hearts could save your life
- Yet another potential benefit of metformin
* This video with Dr. Andrew Huberman of Stanford shows exactly how to do the breathing practice.
This podcast originally aired on March 3, 2023.