Chemotherapy and radiation are two of the front-line weapons in treating cancer. They can be effective, even life-saving, but they can also be brutal, taking a toll on the body that lasts for months. Now a team at UCLA has developed a therapy that might enable the body to bounce back faster after chemo and radiation, and even make treatments like bone marrow transplants easier on patients.
First a little
background. Some cancer treatments use chemotherapy and radiation to kill the
cancer, but they can also damage other cells, including those in the bone
marrow responsible for making blood stem cells. Those cells eventually recover
but it can take weeks or months, and during that time the patient may feel
fatigue and be more susceptible to infections and other problems.
In a CIRM-supported study, UCLA’s Dr. John Chute and his team developed a drug that speeds up the process of regenerating a new blood supply. The research is published in the journal Nature Communications.
They focused their
attention on a protein called PTP-sigma that is found in blood stem cells and
acts as a kind of brake on the regeneration of those cells. Previous studies by
Dr. Chute showed that, after undergoing radiation, mice that have less
PTP-sigma were able to regenerate their blood stem cells faster than mice that
had normal levels of the protein.
So they set out to
identify something that could help reduce levels of PTP-sigma without affecting
other cells. They first identified an organic compound with the charming name
of 6545075 (Chembridge) that was reported to be effective against PTP-sigma.
Then they searched a library of 80,000 different small molecules to find
something similar to 6545075 (and this is why science takes so long).
From that group they
developed more than 100 different drug candidates to see which, if any, were
effective against PTP-sigma. Finally, they found a promising candidate, called DJ009.
In laboratory tests DJ009 proved itself effective in blocking PTP-sigma in
human blood stem cells.
They then tested
DJ009 in mice that were given high doses of radiation. In a news
release Dr. Chute said the results were very encouraging:
“The potency of this compound in animal models was very
high. It accelerated the recovery of blood stem cells, white blood cells and
other components of the blood system necessary for survival. If found to be
safe in humans, it could lessen infections and allow people to be discharged
from the hospital earlier.”
Of the radiated mice, most that were given DJ009
survived. In comparison, those that didn’t get DJ009 died within three weeks.
They saw similar benefits in mice given chemotherapy.
Mice with DJ009 saw their white blood cells – key components of the immune
system – return to normal within two weeks. The untreated mice had dangerously
low levels of those cells at the same point.
It’s encouraging work and the team are already getting
ready for more research so they can validate their findings and hopefully take
the next step towards testing this in people in clinical trials.
There is nothing you can do to prevent or reduce your risk of leukemia. That’s not a very reassuring statement considering that this year alone almost 62,000 Americans will be diagnosed with leukemia; almost 23,000 will die from the disease. That’s why CIRM is funding four clinical trials targeting leukemia, hoping to develop new approaches to treat, and even cure it.
also why our next special Facebook Live “Ask the Stem Cell Team” event is
focused on this issue. Join us on Thursday, August 29th from
1pm to 2pm PDT to hear a discussion about the progress in, and promise of,
stem cell research for leukemia.
two great panelists joining us:
Dr. Crystal Mackall, has many titles including serving as the Founding Director of the Stanford Center for Cancer Cell Therapy. She is using an innovative approach called a Chimeric Antigen Receptor (CAR) T Cell Therapy. This works by isolating a patient’s own T cells (a type of immune cell) and then genetically engineering them to recognize a protein on the surface of cancer cells, triggering their destruction. This is now being tested in a clinical trial funded by CIRM.
Natasha Fooman. To describe Natasha as a patient advocate would not do justice to her experience and expertise in fighting blood cancer and advocating on behalf of those battling the disease. For her work she has twice been named “Woman of the Year” by the Leukemia and Lymphoma Society. In 2011 she was diagnosed with a form of lymphoma that was affecting her brain. Over the years, she would battle lymphoma three times and undergo chemotherapy, radiation and eventually a bone marrow transplant. Today she is cancer free and is a key part of a CIRM team fighting blood cancer.
We hope you’ll join
us to learn about the progress being made using stem cells to combat blood
cancers, the challenges ahead but also the promising signs that we are
advancing the field.
We also hope you’ll take an active role by posting questions on Facebook during the event, or sending us questions ahead of time to email@example.com. We will do our best to address as many as we can.
link to the event, feel free to share this with anyone you think might be interested
in joining us for Facebook Live “Ask the Stem Cell Team about Leukemia”
CIRM’s mission is very simple: to accelerate stem cell treatments to patients with unmet medical needs. Anne Klein’s son, Everett, was a poster boy for that statement. Born with a fatal immune disorder Everett faced a bleak future. But Anne and husband Brian were not about to give up. The following story is one Anne wrote for Parents magazine. It’s testament to the power of stem cells to save lives, but even more importantly to the power of love and the determination of a family to save their son.
My Son Was Born With ‘Bubble Boy’ Disease—But A Gene Therapy Trial Saved His Life
I wish more than anything that my son Everett had not been born with severe combined immunodeficiency (SCID). But I know he is actually one of the lucky unlucky ones. By Anne Klein
As a child in the ’80s, I watched a news story about David Vetter. David was known as “the boy in the bubble” because he was born with severe combined immunodeficiency (SCID), a rare genetic disease that leaves babies with very little or no immune system. To protect him, David lived his entire life in a plastic bubble that kept him separated from a world filled with germs and illnesses that would have taken his life—likely before his first birthday.
I was struck by David’s story. It was heartbreaking and seemed so otherworldly. What would it be like to spend your childhood in an isolation chamber with family, doctors, reporters, and the world looking in on you? I found it devastating that an experimental bone marrow transplant didn’t end up saving his life; instead it led to fatal complications. His mother, Carol Ann Demaret, touched his bare hand for the first and last time when he was 12 years old.
I couldn’t have known that almost 30 years later, my own son, Everett, would be born with SCID too.
Everett’s SCID diagnosis
At birth, Everett was big, beautiful, and looked perfectly healthy. My husband Brian and I already had a 2-and-a-half-year-old son, Alden, so we were less anxious as parents when we brought Everett home. I didn’t run errands with Alden until he was at least a month old, but Everett was out and about with us within a few days of being born. After all, we thought we knew what to expect.
But two weeks after Everett’s birth, a doctor called to discuss Everett’s newborn screening test results. I listened in disbelief as he explained that Everett’s blood sample indicated he may have an immune deficiency.
“He may need a bone marrow transplant,” the doctor told me.
I was shocked. Everett’s checkup with his pediatrician just two days earlier went swimmingly. I hung up and held on to the doctor’s assurance that there was a 40 percent chance Everett’s test result was a false positive.
After five grueling days of waiting for additional test results and answers, I received the call: Everett had virtually no immune system. He needed to be quickly admitted to UCSF Benioff Children’s Hospital in California so they could keep him isolated and prepare to give him a stem cell transplant. UCSF diagnosed him specifically with SCID-X1, the same form David battled.
Beginning SCID treatment
The hospital was 90 miles and more than two hours away from home. Our family of four had to be split into two, with me staying in the hospital primarily with Everett and Brian and Alden remaining at home, except for short visits. The sudden upheaval left Alden confused, shaken, and sad. Brian and I quickly transformed into helicopter parents, neurotically focused on every imaginable contact with germs, even the mildest of which could be life-threatening to Everett.
When he was 7 weeks old, Everett received a stem cell transplant with me as his donor, but the transplant failed because my immune cells began attacking his body. Over his short life, Everett has also spent more than six months collectively in the hospital and more than three years in semi-isolation at home. He’s endured countless biopsies, ultrasounds, CT scans, infusions, blood draws, trips to the emergency department, and medical transports via ambulance or helicopter.
Gene therapy to treat SCID
At age 2, his liver almost failed and a case of pneumonia required breathing support with sedation. That’s when a doctor came into the pediatric intensive care unit and said, “When Everett gets through this, we need to do something else for him.” He recommended a gene therapy clinical trial at the National Institutes of Health (NIH) that was finally showing success in patients over age 2 whose transplants had failed. This was the first group of SCID-X1 patients to receive gene therapy using a lentiviral vector combined with a light dose of chemotherapy.
After the complications from our son’s initial stem cell transplant, Brian and I didn’t want to do another stem cell transplant using donor cells. My donor cells were at war with his body and cells from another donor could do the same. Also, the odds of Everett having a suitable donor on the bone marrow registry were extremely small since he didn’t have one as a newborn. At the NIH, he would receive a transplant with his own, perfectly matched, gene-corrected cells. They would be right at home.
Other treatment options would likely only partially restore his immunity and require him to receive infusions of donor antibodies for life, as was the case with his first transplant. Prior gene therapy trials produced similarly incomplete results and several participants developed leukemia. The NIH trial was the first one showing promise in fully restoring immunity, without a risk of cancer. Brian and I felt it was Everett’s best option. Without hesitation, we flew across the country for his treatment. Everett received the gene therapy in September 2016 when he was 3, becoming the youngest patient NIH’s clinical trial has treated.
It’s been more than two years since Everett received gene therapy and now more than ever, he has the best hope of developing a fully functioning immune system. He just received his first vaccine to test his ability to mount a response. Now 6 years old, he’s completed kindergarten and has been to Disney World. He plays in the dirt and loves shows and movies from the ’80s (maybe some of the same ones David enjoyed).
Everett knows he has been through a lot and that his doctors “fixed his DNA,” but he’s focused largely on other things. He’s vocal when confronted with medical pain or trauma, but seems to block out the experiences shortly afterwards. It’s sad for Brian and me that Everett developed these coping skills at such a young age, but we’re so grateful he is otherwise expressive and enjoys engaging with others. Once in the middle of the night, he woke us up as he stood in the hallway, exclaiming, “I’m going back to bed, but I just want you to know that I love you with all my heart!”
I wish more than anything that Everett had not been born with such a terrible disease and I could erase all the trauma, isolation, and pain. But I know that he is actually one of the lucky unlucky ones. Everett is fortunate his disease was caught early by SCID newborn screening, which became available in California not long before his birth. Without this test, we would not have known he had SCID until he became dangerously ill. His prognosis would have been much worse, even under the care of his truly brilliant and remarkable doctors, some of whom cared for David decades earlier.
When Everett was 4, soon after the gene therapy gave him the immunity he desperately needed, our family was fortunate enough to cross paths with David’s mom, Carol Ann, at an Immune Deficiency Foundation event. Throughout my life, I had seen her in pictures and on television with David. In person, she was warm, gracious, and humble. When I introduced her to Everett and explained that he had SCID just like David, she looked at Everett with loving eyes and asked if she could touch him. As she touched Everett’s shoulder and they locked eyes, Brian and I looked on with profound gratitude.
Anne Klein is a parent, scientist, and a patient advocate for two gene therapy trials funded by the California Institute for Regenerative Medicine. She is passionate about helping parents of children with SCID navigate treatment options for their child.
At CIRM we are privileged to work with many remarkable people who combine brilliance, compassion and commitment to their search for new therapies to help people in need. One of those who certainly fits that description is UC Davis’ Jan Nolta.
This week the UC Davis Newsroom posted a great interview with Jan. Rather than try and summarize what she says I thought it would be better to let her talk for herself.
Talking research, unscrupulous clinics, and sustaining the momentum
In 2007, Jan Nolta
returned to Northern California from St. Louis to lead what was at the
time UC Davis’ brand-new stem cell program. As director of the UC Davis Stem Cell Program
and the Institute for Regenerative Cures, she has overseen the opening
of the institute, more than $140 million in research grants, and dozens
upon dozens of research studies. She recently sat down to answer some
questions about regenerative medicine and all the work taking place at UC Davis Health.
Q: Turning stem cells into cures has been your mission and mantra since you founded the program. Can you give us some examples of the most promising research?
I am so excited about our research. We have about 20 different disease-focused teams.
That includes physicians, nurses, health care staff, researchers and
faculty members, all working to go from the laboratory bench to
patient’s bedside with therapies.
Perhaps the most promising and
exciting research right now comes from combining blood-forming
stem cells with gene therapy. We’re working in about
eight areas right now, and the first cure, something that we definitely
can call a stem cell “cure,” is coming from this combined approach.
doctors will be able to prescribe this type of stem cell therapy.
Patients will use their own bone marrow or umbilical cord stem cells.
Teams such as ours, working in good manufacturing practice
facilities, will make vectors, essentially “biological delivery
vehicles,” carrying a good copy of the broken gene. They will be
reinserted into a patient’s cells and then infused back into the
patient, much like a bone marrow transplant.
“Perhaps the most promising and exciting research right now comes from combining blood-forming stem cells with gene therapy.”
Along with treating the famous bubble baby disease,
where I had started my career, this approach looks very promising for
sickle cell anemia. We’re hoping to use it to treat several different
inherited metabolic diseases. These are conditions characterized by an
abnormal build-up of toxic materials in the body’s cells. They interfere
with organ and brain function. It’s caused by just a single enzyme.
Using the combined stem cell gene therapy, we can effectively put a good
copy of the gene for that enzyme back into a patient’s bone marrow stem
cells. Then we do a bone marrow transplantation and bring back a
person’s normal functioning cells.
The beauty of this therapy is
that it can work for the lifetime of a patient. All of the blood cells
circulating in a person’s system would be repaired. It’s the number one
stem cell cure happening right now. Plus, it’s a therapy that won’t be
rejected. These are a patient’s own stem cells. It is just one type of
stem cell, and the first that’s being commercialized to change cells
throughout the body.
Q: Let’s step back for a moment. In 2004, voters approved Proposition 71.
It has funded a majority of the stem cell research here at UC Davis and
throughout California. What’s been the impact of that ballot measure
and how is it benefiting patients?
We have learned so
much about different types of stem cells, and which stem cell will be
most appropriate to treat each type of disease. That’s huge. We had to
first do that before being able to start actual stem cell therapies. CIRM [California Institute for Regenerative Medicine] has funded Alpha Stem Cell Clinics.
We have one of them here at UC Davis and there are only five in the
entire state. These are clinics where the patients can go for
high-quality clinical stem cell trials approved by the FDA
[U.S. Food and Drug Administration]. They don’t need to go to
“unapproved clinics” and spend a lot of money. And they actually
“By the end of this year, we’ll have 50 clinical trials.”
By the end of this year, we’ll have 50 clinical trials [here at UC Davis Health]. There are that many in the works.
Our Alpha Clinic
is right next to the hospital. It’s where we’ll be delivering a lot of
the immunotherapies, gene therapies and other treatments. In fact, I
might even get to personally deliver stem cells to the operating room
for a patient. It will be for a clinical trial involving people who have
broken their hip. It’s exciting because it feels full circle, from
working in the laboratory to bringing stem cells right to the patient’s
We have ongoing clinical trials
for critical limb ischemia, leukemia and, as I mentioned, sickle cell
disease. Our disease teams are conducting stem cell clinical trials
targeting sarcoma, cellular carcinoma, and treatments for dysphasia [a
swallowing disorder], retinopathy [eye condition], Duchenne muscular
dystrophy and HIV. It’s all in the works here at UC Davis Health.
also great potential for therapies to help with renal disease and
kidney transplants. The latter is really exciting because it’s like a
mini bone marrow transplant. A kidney recipient would also get some
blood-forming stem cells from the kidney donor so that they can better
accept the organ and not reject it. It’s a type of stem cell therapy
that could help address the burden of being on a lifelong regime of
immunosuppressant drugs after transplantation.
Q: You and
your colleagues get calls from family members and patients all the
time. They frequently ask about stem cell “miracle” cures. What should
people know about unproven treatments and unregulated stem cell clinics?
That’s a great question.The number one rule is that if
you’re asked to pay money for a stem cell treatment, don’t do it. It’s a
big red flag.
When it comes to advertised therapies: “The number one rule is that if you’re asked to pay money for a stem cell treatment, don’t do it. It’s a big red flag.”
there are unscrupulous people out there in “unapproved clinics” who
prey on desperate people. What they are delivering are probably not even
stem cells. They might inject you with your own fat cells, which
contain very few stem cells. Or they might use treatments that are not
matched to the patient and will be immediately rejected. That’s
dangerous. The FDA is shutting these unregulated clinics down one at a
time. But it’s like “whack-a-mole”: shut one down and another one pops
On the other hand, the Alpha Clinic is part of our
mission is to help the public get to the right therapy, treatment or
clinical trial. The big difference between those who make patients pay
huge sums of money for unregulated and unproven treatments and UC Davis
is that we’re actually using stem cells. We produce them in rigorously
regulated cleanroom facilities. They are certified to contain at least 99% stem cells.
and family members can always call us here. We can refer them to a
genuine and approved clinical trial. If you don’t get stem cells at the
beginning [of the clinical trial] because you’re part of the placebo
group, you can get them later. So it’s not risky. The placebo is just
saline. I know people are very, very desperate. But there are no miracle
cures…yet. Clinical trials, approved by the FDA, are the only way we’re
going to develop effective treatments and cures.
Scientific breakthroughs take a lot of patience and time. How do you and
your colleagues measure progress and stay motivated?
Motivation? “It’s all for the patients.”
all for the patients. There are not good therapies yet for many
disorders. But we’re developing them. Every day brings a triumph.
Measuring progress means treating a patient in a clinical trial, or
developing something in the laboratory, or getting FDA approval. The big
one will be getting biological license approval from the FDA, which
means a doctor can prescribe a stem cell or gene therapy treatment. Then
it can be covered by a patient’s health insurance.
I’m a cancer
survivor myself, and I’m also a heart patient. Our amazing team here at
UC Davis has kept me alive and in great health. So I understand it from
both sides. I understand the desperation of “Where do I go?” and “What
do I do right now?” questions. I also understand the science side of
things. Progress can feel very, very slow. But everything we do here at
the Institute for Regenerative Cures is done with patients in mind, and
We know that each day is so important when you’re watching
a loved one suffer. We attend patient events and are part of things
like Facebook groups, where people really pour their hearts out. We say
to ourselves, “Okay, we must work harder and faster.” That’s our
motivation: It’s all the patients and families that we’re going to help
who keep us working hard.
Battling cancer is always a balancing act. The methods we use – surgery, chemotherapy and radiation – can help remove the tumors but they often come at a price to the patient. In cases where the cancer has spread to the bone the treatments have a limited impact on the disease, but their toxicity can cause devastating problems for the patient. Now, in a CIRM-supported study, researchers at UC Irvine (UCI) have developed a method they say may be able to change that.
Bone metastasis –
where cancer starts in one part of the body, say the breast, but spreads to the
bones – is one of the most common complications of cancer. It can often result
in severe pain, increased risk of fractures and compression
of the spine. Tackling them is difficult because some cancer cells can
alter the environment around bone, accelerating the destruction of healthy bone
cells, and that in turn creates growth factors that stimulate the growth of the
cancer. It is a vicious cycle where one problem fuels the other.
Now researchers at
UCI have developed a method where they combine engineered mesenchymal stem cells (taken from the bone marrow) with
targeting agents. These act like a drug delivery device, offloading
different agents that simultaneously attack the cancer but protect the bone.
In a news release Weian Zhao, lead author of the study, said:
“What’s powerful about this
strategy is that we deliver a combination of both anti-tumor and anti-bone
resorption agents so we can effectively block the vicious circle between
cancers and their bone niche. This is a safe and almost nontoxic treatment
compared to chemotherapy, which often leaves patients with lifelong issues.”
published in the journal EBioMedicine,
has already been shown to be effective in mice. Next, they hope to be able to
do the safety tests to enable them to apply to the Food and Drug Administration
for permission to test it in people.
The team say if this
approach proves effective it might also be used to help treat other bone-related
diseases such as osteoporosis and multiple myeloma.
We often talk about the important role that patient advocates play in helping advance research. That was demonstrated in a powerful way last week when the CIRM Board approved almost $12 million to fund a clinical trial targeting a rare childhood disorder called cystinosis.
The award, to Stephanie Cherqui and her team at UC San Diego (in collaboration with UCLA) was based on the scientific merits of the program. But without the help of the cystinosis patient advocate community that would never have happened. Years ago the community held a series of fundraisers, bake sales etc., and used the money to help Dr. Cherqui get her research started.
That money enabled Dr. Cherqui to get the data she needed to apply to CIRM for funding to do more detailed research, which led to her award last week. There to celebrate the moment was Nancy Stack. Her testimony to the Board was a moving celebration of how long they have worked to get to this moment, and how much hope this research is giving them.
Hello my name is Nancy Stack and I am the founder and president of the Cystinosis Research Foundation. Our daughter Natalie was diagnosed with cystinosis when she was an infant.
a rare disease that is characterized by the abnormal accumulation of cystine in
every cell in the body. The build-up of
cystine eventually destroys every organ in the body including the kidneys,
eyes, liver, muscles, thyroid and brain.
The average age of death from cystinosis and its complications is 28
years of age.
children and adults with cystinosis, there are no healthy days. They take
between 8-12 medications around the clock every day just to stay alive –
Natalie takes 45 pills a day. It is a
relentless and devastating disease.
complications abound and our children’s lives are filled with a myriad of
symptoms and treatments – there are g-tube feedings, kidney transplants, bone
pain, daily vomiting, swallowing
difficulties, muscle wasting, severe gastrointestinal side effects and for some
the Foundation in 2003. We have worked
with and funded Dr. Stephanie Cherqui since 2006. As a foundation, our resources are limited
but we were able to fund the initial grants for Stephanie’s Stem Cell studies. When CIRM awarded a grant
to Stephanie in 2016, it allowed her to complete the studies, file the IND and
as a result, we now have FDA approval
for the clinical trial. Your support has changed the course of this
When the FDA
approved the clinical trial for cystinosis last year, our community was filled
with a renewed sense of hope and optimism.
I heard from 32 adults with cystinosis – all of them interested in the
clinical trial. Our adults know that
this is their only chance to live a full life. Without this treatment, they
will die from cystinosis. In every
email I received, there was a message of hope and gratitude.
I received an
email from a young woman who said this, “It’s a new awakening to learn this
morning that human clinical trials have been approved by the FDA. I reiterate
my immense interest to participate in this trial as soon as possible because my
quality of life is at a low ebb and the trial is really my only hope. Time is
And a mom of a 19 year old young man who wants to be the first
patient in the trial wrote and said this, “On the day the trial was announced I started to cry tears of pure
happiness and I thought, a mother somewhere gets to wake up and have a child who
will no longer have cystinosis. I felt so happy for whom ever that mom would
be….I never imagined that the mom I was thinking about could be me. I am so
humbled to have this opportunity for my son to try to live disease free.
My own daughter ran into my arms that day and we cried tears of
joy – finally, the hope we had clung to was now a reality. We had come full
circle. I asked Natalie how it felt to
know that she could be cured and she said, “I have spent my entire life thinking
that I would die from cystinosis in my 30s but now, I might live a full life
and I am thinking about how much that changes how I think about my future. I never
planned too far ahead but now I can”.
As a mother, words can’t possible convey what it feels like to know that my child has a chance to live a long, healthy life free of cystinosis – I can breathe again. On behalf of all the children and adults with cystinosis, thank you for funding Dr. Cherqui, for caring about our community, for valuing our children and for making this treatment a reality. Our community is ready to start this trial – thank you for making this happen.
CIRM will be celebrating the role of patient advocates at a free event in Los Angeles tomorrow. It’s at the LA Convention Center and here are the details. And did I mention it’s FREE!
Tue, June 25, 2019 – 6:00 PM – 7:00 PM PDT
Petree Hall C., Los Angeles Convention Center, 1201 South Figueroa Street Los Angeles, CA 90015
And on Wednesday, USC is holding an event highlighting the progress being made in fighting diseases that destroy vision. Here’s a link to information about the event.
Today the governing Board of the California Institute for
Regenerative Medicine (CIRM) approved a grant of almost $12 million to Dr.
Stephanie Cherqui at the University of California, San Diego (UCSD) to conduct
a clinical trial for treatment of cystinosis.
award brings the total number of CIRM funded clinical trials to 55.
a rare disease that primarily affects children and young adults, and leads to
premature death, usually in early adulthood. Patients inherit
defective copies of a gene called CTNS, which results in abnormal accumulation
of an amino acid called cystine in all cells of the body. This buildup of cystine can lead to
multi-organ failure, with some of earliest and most pronounced effects on the
kidneys, eyes, thyroid, muscle, and pancreas.
Many patients suffer end-stage kidney failure and severe vision defects
in childhood, and as they get older, they are at increased risk for heart
disease, diabetes, bone defects, and neuromuscular defects. There is currently a drug treatment for
cystinosis, but it only delays the progression of the disease, has severe side
effects and is expensive.
Dr. Cherqui’s clinical trial will use a gene therapy
approach to modify a patient’s own blood stem cells with a functional version
of the defective CTNS gene. Based on pre-clinical
data, the approach is to reintroduce the corrected stem cells into the patient
to give rise to blood cells that will reduce cystine buildup in affected
Because this is the first time this approach has been tested in patients, the primary goal of the clinical trial is to see if the treatment is safe. In addition, patients will be monitored for improvements in the symptoms of their disease. This award is in collaboration with the University of California, Los Angeles which will handle the manufacturing of the therapy.
CIRM has also funded the preclinical work
for this study, which involved completing the testing needed to apply to the
Food and Drug Administration (FDA) for permission to start a clinical trial in
“CIRM has funded 24 clinical stage programs utilizing
cell and gene medicine approaches to date,” says Maria T. Millan, M.D., the
President and CEO of CIRM. “This project
continues to broaden the scope of unmet medical need we can impact with these
types of approaches.”
A transplant can be a lifesaving procedure for many people across the United States. In fact, according to the Health Resources & Services Administration, 36,528 transplants were performed in 2018. However, as of January 2019, the number of men, women, and children on the national transplant waiting list is over 113,000, with 20 people dying each day waiting for a transplant and a new person being added to the list every 10 minutes.
Before considering a transplant, there needs to be an immunological match between the donated tissue and/or blood stem cells and the recipient. To put it simply, a “match” indicates that the donor’s cells will not be marked by the recipient’s immune cells as foreign and begin to attack it, a process known as graft-versus-host disease. Unfortunately, these matches can be challenging to find, particularly for some ethnic minorities. Often times, immunosuppression drugs are also needed in order to prevent the foreign cells from being attacked by the body’s immune system. Additionally, chemotherapy and radiation are often needed as well.
Fortunately, a CIRM-funded study at Stanford has shown some promising results towards addressing the issue of matching donor cells and recipient. Dr. Irv Weissman and his colleagues at Stanford have found a way to prepare mice for a transplant of blood stem cells, even when donor and recipient are an immunological mismatch. Their method involved using a combination of six specific antibodies and does not require ongoing immunosuppression.
The combination of antibodies did this by eliminating several types of immune cells in the animals’ bone marrow, which allowed blood stem cells to engraft and begin producing blood and immune cells without the need for continued immunosuppression. The blood stem cells used were haploidentical, which, to put it simply, is what naturally occurs between parent and child, or between about half of all siblings.
Additional experiments also showed that the mice treated with the six antibodies could also accept completely mismatched purified blood stem cells, such as those that might be obtained from an embryonic stem cell line.
The results established in this mouse model could one day lay the foundation necessary to utilize this approach in humans after conducting clinical trials. The idea would be that a patient that needs a transplanted organ could first undergo a safe, gentle transplant with blood stem cells derived in the laboratory from embryonic stem cells. The same embryonic stem cells could also then be used to generate an organ that would be fully accepted by the recipient without requiring the need for long-term treatment with drugs to suppress the immune system.
“With support by the California Institute for Regenerative Medicine, we’ve been able to make important advances in human embryonic stem cell research. In the past, these stem cell transplants have required a complete match to avoid rejection and reduce the chance of graft-versus-host disease. But in a family with four siblings the odds of having a sibling who matches the patient this closely are only one in four. Now we’ve shown in mice that a ‘half match,’ which occurs between parents and children or in two of every four siblings, works without the need for radiation, chemotherapy or ongoing immunosuppression. This may open up the possibility of transplant for nearly everyone who needs it. Additionally, the immune tolerance we’re able to induce should in the future allow the co-transplantation of [blood] stem cells and tissues, such as insulin-producing cells or even organs generated from the same embryonic stem cell line.”
The full results to this study were published in Cell Stem Cell.
Blood stem cells offer promise for a variety of immune and blood related disorders such as sickle cell disease and leukemia. Like other stem cells, blood stem cells have the ability to generate additional blood stem cells in a process called self-renewal. Additionally, they are able to generate blood cells in a process called differentiation. These newly generated blood cells have the potential to be utilized for transplantations and gene therapies.
However, two limitations have hindered the progress made in this field. One problem relates to the amount of blood stem cells needed to make a potential transplantation or gene therapy viable. Unfortunately, it has been challenging to isolate and grow blood stem cells in large quantity needed for these approaches. A part of this reason relates to getting the blood stem cells to self-renew rather than differentiate.
The second problem involves the existing blood stem cells in the patient’s body prior to transplantation. In order for the procedure to work, the patient’s own blood stem cells must be eliminated to make space for the transplanted blood stem cells. This is done through a process known as conditioning, which typically involves chemotherapy and/or radiation. Unfortunately, chemotherapy and radiation can cause life-threatening side effects due to its toxicity, particularly in pediatric patients, such as growth retardation, infertility and secondary cancer in later life. Very sick or elderly patients are unable to tolerate this conditioning process, making them ineligible for transplants.
A CIRM funded study by a team at Stanford and the University of Tokyo has unlocked the code related to the generation of blood stem cells.
The collaborative team was able to modify the components used to grow blood stem cells. By making these modifications, which effects the growth and physical conditions of blood stem cells, the researchers have shown for the first time that it’s possible to get blood stem cells from mice to renew themselves hundreds or even thousands of times within a period of just 28 days.
Furthermore, the team showed that when they transplanted the newly grown cells into mice that had not undergone conditioning, the donor cells had engrafted and remained functional.
The team also found that gene editing technology such as CRISPR could be used while growing an adequate supply of blood stem cells for transplantation. This opens the possibility of obtaining a patient’s own blood stem cells, correcting the problematic gene, and reintroducing these back to the patient.
In a news release, Dr. Hiromitsu Nakauchi, a senior author of the study, is quoted as saying,
“For 50 years, researchers from laboratories around the world have been seeking ways to grow these cells to large numbers. Now we’ve identified a set of conditions that allows these cells to expand in number as much as 900-fold in just one month. We believe this approach could transform how [blood] stem cell transplants and gene therapy are performed in humans.”
For years researchers have struggled to create human blood stem cells in the lab. They have done it several times with animal models, but the human kind? Well, that’s proved a bit trickier. Now a CIRM-funded team at UC San Diego (UCSD) think they have cracked the code. And that would be great news for anyone who may ever need a bone marrow transplant.
Why are blood stem cells important? Well, they help create our red and white blood cells and platelets, critical elements in carrying oxygen to all our organs and fighting infections. They have also become one of the most important weapons we have to combat deadly diseases like leukemia and lymphoma. Unfortunately, today we depend on finding a perfect or near-perfect match to make bone marrow transplants as safe and effective as possible and without a perfect match many patients miss out. That’s why this news is so exciting.
Researchers at UCSD found that the process of creating new blood stem cells depends on the action of three molecules, not two as was previously thought.
Here’s where it gets
a bit complicated but stick with me. The team worked with zebrafish, which use
the same method to create blood stem cells as people do but also have the
advantage of being translucent, so you can watch what’s going on inside them as
it happens. They noticed that a molecule
called Wnt9a touches down on a receptor called Fzd9b and brings along with it
something called the epidermal growth factor receptor (EGFR). It’s the
interaction of these three together that turns a stem cell into a blood cell.
In a news release, Stephanie Grainger, the first author of the
study published in Nature Cell Biology, said this discovery could help lead to new
ways to grow the cells in the lab.
“Previous attempts to develop blood stem cells in a
laboratory dish have failed, and that may be in part because they didn’t take
the interaction between EGFR and Wnt into account.”
If this new approach helps the team generate blood stem cells in the lab these could be used to create off-the-shelf blood stem cells, instead of bone marrow transplants, to treat people battling leukemia and/or lymphoma.