A few weeks ago we held a Facebook Live “Ask the Stem Cell Team About Parkinson’s Disease” event. As you can imagine we got lots of questions but, because of time constraints, only had time to answer a few. Thanks to my fabulous CIRM colleagues, Dr. Lila Collins and Dr. Kent Fitzgerald, for putting together answers to some of the other questions. Here they are.
Q:It seems like we have been hearing for years that stem cells can help people with Parkinson’s, why is it taking so long?
A: Early experiments in Sweden using fetal tissue did provide a proof of concept for the strategy of replacing dopamine producing cells damaged or lost in Parkinson’s disease (PD) . At first, this seemed like we were on the cusp of a cell therapy cure for PD, however, we soon learned based on some side effects seen with this approach (in particular dyskinesias or uncontrollable muscle movements) that the solution was not as simple as once thought.
While this didn’t produce the answer it did provide some valuable lessons.
The importance of dopaminergic (DA) producing cell type and the location in the brain of the transplant. Simply placing the replacement cells in the brain is not enough. It was initially thought that the best site to place these DA cells is a region in the brain called the SN, because this area helps to regulate movement. However, this area also plays a role in learning, emotion and the brains reward system. This is effectively a complex wiring system that exists in a balance, “rewiring” it wrong can have unintended and significant side effects.
Another factor impacting progress has been understanding the importance of disease stage. If the disease is too advanced when cells are given then the transplant may no longer be able to provide benefit. This is because DA transplants replace the lost neurons we use to control movement, but other connected brain systems have atrophied in response to losing input from the lost neurons. There is a massive amount of work (involving large groups and including foundations like the Michael J Fox Foundation) seeking to identify PD early in the disease course where therapies have the best chance of showing an effect. Clinical trials will ultimately help to determine the best timing for treatment intervention.
Ideally, in addition to the cell therapies that would replace lost or damaged cells we also want to find a therapy that slows or stops the underlying biology causing progression of the disease.
So, I think we’re going to see more gene therapy trials including those targeting the small minority of PD that is driven by known mutations. In fact, Prevail Therapeutics will soon start a trial in patients with GBA1 mutations. Hopefully, replacing the enzyme in this type of genetic PD will prevent degeneration.
And, we are also seeing gene therapy approaches to address forms of PD that we don’t know the cause, including a trial to rescue sick neurons with GDNF which is a neurotrophic factor (which helps support the growth and survival of these brain cells) led by Dr Bankiewicz and trials by Axovant and Voyager, partnered with Neurocrine aimed at restoring dopamine generation in the brain.
A small news report came out earlier this year about a recently completed clinical trial by Roche Pharma and Prothena. This addressed the build up in the brain of what are called lewy bodies, a problem common to many forms of PD. While the official trial results aren’t published yet, a recent press release suggests reason for optimism. Apparently, the treatment failed to statistically improve the main clinical measurement, but other measured endpoints saw improvement and it’s possible an updated form of this treatment will be tested again in the hopes of seeing an improved effect.
Finally, I’d like to call attention to the G force trials. Gforce is a global collaborative effort to drive the field forward combining lessons learned from previous studies with best practices for cell replacement in PD. These first-in-human safety trials to replace the dopaminergic neurons (DANs) damaged by PD have shared design features including identifying what the best goals are and how to measure those.
And the Summit PD trial, Dr Jeanne Loring of Aspen Neuroscience.
Taken together these should tell us quite a lot about the best way to replace these critical neurons in PD.
As with any completely novel approach in medicine, much validation and safety work must be completed before becoming available to patients
The current approach (for cell replacement) has evolved significantly from those early studies to use cells engineered in the lab to be much more specialized and representing the types believed to have the best therapeutic effects with low probability of the side effects (dyskinesias) seen in earlier trials.
If we don’t really know the cause of Parkinson’s disease, how can we cure it or develop treatments to slow it down?
PD can now be divided into major categories including 1. Sporadic, 2. Familial.
For the sporadic cases, there are some hallmarks in the biology of the neurons affected in the disease that are common among patients. These can be things like oxidative stress (which damages cells), or clumps of proteins (like a-synuclein) that serve to block normal cell function and become toxic, killing the DA neurons.
The second class of “familial” cases all share one or more genetic changes that are believed to cause the disease. Mutations in genes (like GBA, LRRK2, PRKN, SNCA) make up around fifteen percent of the population affected, but the similarity in these gene mutations make them attractive targets for drug development.
CIRM has funded projects to generate “disease in a dish” models using neurons made from adults with Parkinson’s disease. Stem cell-derived models like this have enabled not only a deep probing of the underlying biology in Parkinson’s, which has helped to identify new targets for investigation, but have also allowed for the testing of possible therapies in these cell-based systems.
iPSC-derived neurons are believed to be an excellent model for this type of work as they can possess known familial mutations but also show the rest of the patients genetic background which may also be a contributing factor to the development of PD. They therefore contain both known and unknown factors that can be tested for effective therapy development.
I have heard of scientists creating things called brain organoids, clumps of brain cells that can act a little bit like a brain. Can we use these to figure out what’s happening in the brain of people with Parkinson’s and to develop treatments?
There is considerable excitement about the use of brain organoids as a way of creating a model for the complex cell-to-cell interactions in the brain. Using these 3D organoid models may allow us to gain a better understanding of what happens inside the brain, and develop ways to treat issues like PD.
The organoids can contain multiple cell types including microglia which have been a hot topic of research in PD as they are responsible for cleaning up and maintaining the health of cells in the brain. CIRM has funded the Salk Institute’s Dr. Fred Gage’s to do work in this area.
If you go online you can find lots of stem cells clinics, all over the US, that claim they can use stem cells to help people with Parkinson’s. Should I go to them?
In a word, no! These clinics offer a wide variety of therapies using different kinds of cells or tissues (including the patient’s own blood or fat cells) but they have one thing in common; none of these therapies have been tested in a clinical trial to show they are even safe, let alone effective. These clinics also charge thousands, sometimes tens of thousands of dollars these therapies, and because it’s not covered by insurance this all comes out of the patient’s pocket.
These predatory clinics are peddling hope, but are unable to back it up with any proof it will work. They frequently have slick, well-designed websites, and “testimonials” from satisfied customers. But if they really had a treatment for Parkinson’s they wouldn’t be running clinics out of shopping malls they’d be operating huge medical centers because the worldwide need for an effective therapy is so great.
Here’s a link to the page on our website that can help you decide if a clinical trial or “therapy” is right for you.
Is it better to use your own cells turned into brain cells, or cells from a healthy donor?
This is the BIG question that nobody has evidence to provide an answer to. At least not yet.
Let’s start with the basics. Why would you want to use your own cells? The main answer is the immune system. Transplanted cells can really be viewed as similar to an organ (kidney, liver etc) transplant. As you likely know, when a patient receives an organ transplant the patient’s immune system will often recognize the tissue/organ as foreign and attack it. This can result in the body rejecting what is supposed to be a life-saving organ. This is why people receiving organ transplants are typically placed on immunosuppressive “anti-rejection “drugs to help stop this reaction.
In the case of transplanted dopamine producing neurons from a donor other than the patient, it’s likely that the immune system would eliminate these cells after a short while and this would stop any therapeutic benefit from the cells. A caveat to this is that the brain is a “somewhat” immune privileged organ which means that normal immune surveillance and rejection doesn’t always work the same way with the brain. In fact analysis of the brains collected from the first Swedish patients to receive fetal transplants showed (among other things) that several patients still had viable transplanted cells (persistence) in their brains.
Transplanting DA neurons made from the patient themselves (the iPSC method) would effectively remove this risk of the immune system attack as the cells would not be recognized as foreign.
CIRM previously funded a discovery project with Jeanne Loring from Scripps Research Institute that sought to generate DA neurons from Parkinson’s patients for use as a potential transplant therapy in these same patients. This project has since been taken on by a company formed, by Dr Loring, called Aspen Neuroscience. They hope to bring this potential therapy into clinical trials in the near future.
A commonly cited potential downside to this approach is that patients with genetic (familial) Parkinson’s would be receiving neurons generated with cells that may have the same mutations that caused the problem in the first place. However, as it can typically take decades to develop PD, these cells could likely function for a long time. and prove to be better than any current therapies.
Creating cells from each individual patient (called autologous) is likely to be very expensive and possibly even cost-prohibitive. That is why many researchers are working on developing an “off the shelf” therapy, one that uses cells from a donor (called allogeneic)would be available as and when it’s needed.
When the coronavirus happened, it seemed as if overnight the FDA was approving clinical trials for treatments for the virus. Why can’t it work that fast for Parkinson’s disease?
While we don’t know what will ultimately work for COVID-19, we know what the enemy looks like. We also have lots of experience treating viral infections and creating vaccines. The coronavirus has already been sequenced, so we are building upon our understanding of other viruses to select a course to interrupt it. In contrast, the field is still trying to understand the drivers of PD that would respond to therapeutic targeting and therefore, it’s not precisely clear how best to modify the course of neurodegenerative disease. So, in one sense, while it’s not as fast as we’d like it to be, the work on COVID-19 has a bit of a head start.
Much of the early work on COVID-19 therapies is also centered on re-purposing therapies that were previously in development. As a result, these potential treatments have a much easier time entering clinical trials as there is a lot known about them (such as how safe they are etc.). That said, there are many additional therapeutic strategies (some of which CIRM is funding) which are still far off from being tested in the clinic.
The concern of the Food and Drug Administration (FDA) is often centered on the safety of a proposed therapy. The less known, the more cautious they tend to be.
As you can imagine, transplanting cells into the brain of a PD patient creates a significant potential for problems and so the FDA needs to be cautious when approving clinical trials to ensure patient safety.
When I first saw the headline for this story I thought of the nursery rhyme about the three blind mice. Finally, they’ll be able to see the farmer’s wife coming at them with a carving knife. But the real-world implications are of this are actually pretty exciting.
Researchers at the National Institute of Health’s National Eye Institute took skin cells from mice and directly reprogrammed them into becoming light sensitizing cells in the eye, the kind that are often damaged and destroyed by diseases like macular degeneration or retinitis pigmentosa.
What’s particularly interesting about this is that it bypassed the induced pluripotent stem cell (iPSC) stage where researchers turn the skin cells into embryonic-like cells, then turn those into the cells found in the eye.
In a news release, Anand Swaroop of the NEI says this more direct approach has a number of advantages: “This is the first study to show that direct, chemical reprogramming can produce retinal-like cells, which gives us a new and faster strategy for developing therapies for age-related macular degeneration and other retinal disorders caused by the loss of photoreceptors.”
After converting the skin cells into cells called rod photoreceptors – the light sensing cells found in the back of the eye – the team transplanted them into blind mice. One month later they tested the mice to see if there had been any change in vision. There had; 43 percent of the mice reacted to light exposure, something they hadn’t done before.
Biraj Mahato, the study’s first author, said that three months later, the transplanted cells were still alive and functioning. “Even mice with severely advanced retinal degeneration, with little chance of having living photoreceptors remaining, responded to transplantation. Such findings suggest that the observed improvements were due to the lab-made photoreceptors rather than to an ancillary effect that supported the health of the host’s existing photoreceptors.”
Obviously there is a lot of work still to do before we can even begin to think about trying something like this in people. But this is certainly an encouraging start.
On March 19th we held a special Facebook Live “Ask the Stem Cell Team About Autism” event. We were fortunate enough to have two great experts – Dr. Alysson Muotri from UC San Diego, and CIRM’s own Dr. Kelly Shepard. As always there is a lot of ground to cover in under one hour and there are inevitably questions we didn’t get a chance to respond to. So, Dr. Shepard has kindly agreed to provide answers to all the key questions we got on the day.
If you didn’t get a chance to see the event you can watch the video here. And feel free to share the link, and this blog, with anyone you think might be interested in the material.
Can umbilical cord blood stem cells help reduce some of the symptoms?
This question was addressed by Dr. Muotri in the live presentation. To recap, a couple of clinical studies have been reported from scientists at Duke University and Sutter Health, but the results are not universally viewed as conclusive. The Duke study, which focused on very young children, reported some improvements in behavior for some of the children after treatment, but it is important to note that this trial had no placebo control, so it is not clear that those patients would not have improved on their own. The Duke team has moved forward with larger trial and placebo control.
Does it have to be the child’s own cord blood or could donated blood work too?
In theory, a donated cord product could be used for similar purposes as a child’s own cord, but there is a caveat- the donated cord tissues must have some level of immune matching with the host in order to not be rejected or lead to other complications, which under certain circumstances, could be serious.
Some clinics claim that the use of fetal stem cells can help stimulate improved blood and oxygen flow to the brain. Could that help children with autism?
Fetal stem cells have been tested in FDA approved/sanctioned clinical trials for certain brain conditions such as stroke and Parkinson Disease, where there is clearer understanding of how and which parts of the brains are affected, which nerve cells have been lost or damaged, and where there is a compelling biological rationale for how certain properties the transplanted cells, such as their anti-inflammatory properties, could provide benefit.
In his presentation, Dr. Muotri noted that neurons are not lost in autistic brains, so there is nothing that would be “replaced” by such a treatment. And although some forms of autism might include inflammation that could potentially be mitigated, it is unlikely that the degree of benefit that might come from reducing inflammation would be worth the risks of the treatment, which includes intracranial injection of donated material. Unfortunately, we still do not know enough about the specific causes and features of autism to determine if and to what extent stem cell treatments could prove helpful. But we are learning more every day, especially with some of the new technologies and discoveries that have been enabled by stem cell technology.
Some therapies even use tissue from sheep claiming that a pill containing sheep pancreas can migrate to and cure a human pancreas, pills containing sheep brains can help heal human brains. What are your thoughts on those?
For some conditions, there may be a scientific rationale for how a specific drug or treatment could be delivered orally, but this really depends on the underlying biology of the condition, the means by which the drug exerts its effect, and how quickly that drug or substance will be digested, metabolized, or cleared from the body’s circulation. Many drugs that are delivered orally do not reach the brain because of the blood-brain barrier, which serves to isolate and protect the brain from potentially harmful substances in the blood circulation. For such a drug to be effective, it would have to be stable within the body for a period of time, and be something that could exert its effects on the brain either directly or indirectly.
Sheep brain or pancreas (or any other animal tissue consumed) in a pill form would be broken down into basic components immediately by digestion, i.e. amino acids, sugars, much like any other meat or food. Often complex treatments designed to be specifically targeted to the brain are delivered by intra-cranial/intrathecal injection, or by developing special strategies to evade the blood brain barrier, a challenge that is easier said than done. For autism, there is still a lot to be learned regarding how a therapeutic intervention might work to help people, so for now, I would caution against the use of dietary supplements or pills that are not prescribed or recommended by your doctor.
What are the questions parents should ask before signing up for any stem cell therapy
These are definitely strange, unusual and challenging times. Every day seems to bring new restrictions on what we can and should do. All, of course, in the name of protecting us and helping us avoid a potentially deadly virus. We all hope this will soon pass but we also know the bigger impact of the coronavirus is likely to linger for many months, perhaps even years.
With that in mind a few people have asked us why we are still going ahead with our Facebook Live ‘Ask the Stem Cell Team About Autism’ event this Thursday, March 19th at 12pm PDT. It’s a good question. And the answer is simple. Because there is still a need for good, thoughtful information about the potential for stem cells to help families who have a loved one with autism. And because we still need to do all we can to dispel the bad information out there and warn people about the bogus clinics offering unproven therapies.
In many ways Facebook Live is the perfect way to deliver this information. It allows us to reach out to large numbers of people without having them in the same room. We can educate not contaminate.
And we have some great experts to discuss the use of stem cells in helping people with autism.
The event features Dr. Alysson Muotri from UC San Diego. We have written about his work with stem cells for autism in the past. And CIRM’s own Associate Director for Discovery and Translation, Dr. Kelly Shepard.
But we also want you to be a part of this as well. So, join us online for the event. You can post comments and questions during the event, and we’ll do our best to answer them. Or you can send us in questions ahead of time to email@example.com.
If you were unable to tune in while we were live, not to worry, you you can watch it here on our Facebook page
Way back in 2013, the CIRM Board invested $32 million in a project to create an iPSC Bank. The goal was simple; to collect tissue samples from people who have different diseases, turn those samples into high quality stem cell lines – the kind known as induced pluripotent stem cells (iPSC) – and create a facility where those lines can be stored and distributed to researchers who need them.
Fast forward almost seven years and that idea has now become the largest public iPSC bank in the world. The story of how that happened is the subject of a great article (by CIRM’s Dr. Stephen Lin) in the journal Science Direct.
In 2013 there was a real need for the bank. Scientists around the world were doing important research but many were creating the cells they used for that research in different ways. That made it hard to compare one study to another and come up with any kind of consistent finding. The iPSC Bank was designed to change that by creating one source for high quality cells, collected, processed and stored under a single, consistent method.
Tissue samples – either blood or skin – were collected from thousands of individuals around California. Each donor underwent a thorough consent process – including being shown a detailed brochure – to explain what iPS cells are and how the research would be done.
The diseases to be studied through this bank include:
Age-Related Macular Degeneration (AMD)
Autism Spectrum Disorder (ASD)
Cardiomyopathies (heart conditions)
Fatty Liver diseases
Hepatitis C (HCV)
Primary Open Angle Glaucoma
The samples were screened to make sure they were safe – for example the blood was tested for HBV and HIV – and then underwent rigorous quality control testing to make sure they met the highest standards.
Once approved the samples were then turned into iPSCs at a special facility at the Buck Institute in Novato and those lines were then made available to researchers around the world, both for-profit and non-profit entities.
Scientists are now able to use these cells for a wide variety of uses including disease modeling, drug discovery, drug development, and transplant studies in animal research models. It gives them a greater ability to study how a disease develops and progresses and to help discover and test new drugs or other therapies
The Bank, which is now run by FUJIFILM Cellular Dynamics, has become a powerful resource for studying genetic variation between individuals, helping scientists understand how disease and treatment vary in a diverse population. Both CIRM and Fuji Film are committed to making even more improvements and additions to the collection in the future to ensure this is a vital resource for researchers for years to come.
Do an online search for “autism stem cells” and you quickly come up with numerous websites offering stem cell therapies for autism. They offer encouraging phrases like “new and effective approach” and “a real, lasting treatment.” They even include dense scientific videos featuring people like Dr. Arnold Caplan, a professor at Case Western Reserve University who is known as the “father of the mesenchymal stem” (it would be interesting to know if Dr. Caplan knows he is being used as a marketing tool?)
The problem with these sites is that they are offering “therapies” that have never been proven to be safe, let alone effective. They are also very expensive and are not covered by insurance. Essentially they are preying on hope, the hope that any parent of a child with autism spectrum disorder (ASD) will do anything and everything they can to help their child.
But there is encouraging news about stem cells and autism, about their genuine potential to help children with ASD. That’s why we are holding a special Facebook Live “Ask the Stem Cell Team” about Autism on Thursday, March 19th at noon (PDT).
The event features Dr. Alysson Muotri from UC San Diego. We have written about his work with stem cells for autism in the past. And CIRM’s own Associate Director for Discovery and Translation, Dr. Kelly Shephard.
We’ll take a look at Dr. Muotri’s work and also discuss the work of other researchers in the field, such as Dr. Joanne Kurtzberg’s work at Duke University.
But we also want you to be a part of this as well. So, join us online for the event. You can post comments and questions during the event, and we’ll do our best to answer them. Or you can send us in questions ahead of time to firstname.lastname@example.org.
By Kelly Shepard, PhD., CIRM’s Associate Director, Discovery & Translation
CIRM has previously blogged about advances in treating certain forms of “bubble baby” disease”, where a person is born with a defect in their blood forming stem cells that results in a deficient immune system, rendering them vulnerable to lethal infections by all manner of bacteria, virus or germ.
If a suitable donor can be found, or if the patient’s own defective cells can be corrected through gene therapy approaches, it is now possible to treat or cure such disorders through a bone marrow transplant. In this procedure, healthy blood stem cells are infused into the patient, taking up residence in his or her bone marrow and dividing to give rise to functioning immune cells such as T cells and B cells.
Unfortunately, there is another type of “bubble baby” disease that cannot be treated by providing healthy blood stem cells, because the defective immune system is caused by a different culprit altogether- a missing or dysfunctional thymus.
T Cells Go to School
What is a thymus? Most of us give little thought to this leaf-shaped organ, which is large and important in our early childhoods, but becomes small and inconspicuous as we age. This transformation belies the critical role a thymus plays in the development of our adaptive immune systems, which takes place in our youth: to prepare our bodies to fight infections for the rest of our lives.
One might think of the thymus as a “school”, where immature T cells go to “learn” how to recognize and attack foreign antigens (surface markers), such as those found on microorganisms or tissues from other individuals. The thymus also “teaches” our immune system to distinguish “self” from “other” by eliminating any T cells that attack our own tissues. Without this critical function, our immune system could inadvertently turn against us, causing serious autoimmune disorders such as ulcerative colitis and myasthenia gravis.
Many children with a severely deficient or absent thymus, referred to as athymia, have inherited a chromosome that is missing a key stretch of genes on a region called 22q11. Doctors believe perhaps 1/2000-1/4000 babies are born with some type of deletion in this region, which leads to a variable spectrum of disorders called 22q11 syndrome that can affect just about any part of the body, and can even cause learning disabilities and mental illness.
Individuals with one form of 22q11, called DiGeorge Syndrome, are particularly affected in the heart, thymus, and parathyroid glands. In the United States, about 20 infants are born per year with the “complete” and most severe form of DiGeorge Syndrome, who lack a thymus altogether, and have severely depressed numbers of T cells for fighting infections. Without medical intervention, this condition is usually fatal by 24 months of age.
Optimism and Setback
Although there are no therapies approved by the Food and Drug Administration (FDA) for pediatric athymia, Dr. Mary Louise Markert at Duke University and Enzyvant, Inc. have been pioneering an experimental approach to treat children with complete DiGeorge syndrome.
In this procedure, discarded thymic tissues are collected from infants undergoing cardiac surgery, where some of the thymus needs to be removed in order for the surgeon to gain access to the heart. These tissues are processed to remove potentially harmful donor T cells and then transplanted into the thigh of an athymic DiGeorge patient.
Results from early clinical trials seemed promising, with more than 70% of patients surviving, including several who are now ten years post-transplant. Based on those results, in June of 2019 Enzyvant applied to the FDA for a Biologics License Application (BLA), which is needed to be able to sell the therapy in the US. Unfortunately, only a few months later, Enzyvant announced that the FDA had declined to approve the BLA due to manufacturing concerns.
While it may be possible to address these issues in time, the need to step back to the drawing board was a devastating blow to the DiGeorge Community, who have waited decades for a promising treatment to emerge on the horizon.
Despite the setback, there is reason to hope. In early 2019, CIRM granted a “Quest” Award to team of investigators at Stanford University to develop a novel stem cell based approach for treating thymic deficiency. Co-led by Katja Weinacht, a pediatric hematologist/oncologist, and Vittorio Sebastiano, a stem cell expert and developmental biologist, the team’s strategy is to coax induced pluripotent stem cells (iPS) in the laboratory to differentiate into thymic tissue, which could then be transplanted into patients using the route pioneered by Duke and Enzyvant.
The beauty of this new approach is that pluripotent stem cells are essentially immortal in culture, providing an inexhaustible supply of fresh thymic cells for transplant, thereby allowing greater control over the quality and consistency of donor tissues. A second major advantage is the possibility of using pluripotent cells from the patient him/herself as the source, which should be perfectly immune-matched and alleviate the risk of rejection and autoimmunity that comes with use of donated tissues.
Sounds easy, so what are the challenges? As with many regenerative medicine approaches, the key is getting a pluripotent stem cell to differentiate into the right type of cells in the lab, which is a very different environment than what cells experience naturally when they develop in the context of an embryo and womb, where many cells are interacting and providing complex, instructive cues to one another. The precise factors and timing all need to be worked out and in most cases, this is done with an incomplete knowledge of human development.
A second challenge relates to using cells from DiGeorge patients to produce thymic tissue, which are missing several genes on their 22nd chromosome and will likely require sophisticated genetic engineering to restore this ability.
Fortunately, Drs. Weinacht and Sebastiano are up to the challenge, and have already made progress in differentiating human induced pluripotent stem cells (iPS) into thymic lineage intermediates that appear to be expressing the right proteins at the right time. They plan to combine these cells with engineered materials to create a three-dimensional (3D) tissue that more closely resembles an authentic organ, and which can be tested for functionality in athymic mice.
There is more work to be done, but these advances, along with continued technological improvements and renewed efforts from Enzyvant, could forge a path to the clinic and lead to a brighter future for patients suffering from congenital athymia and other forms of thymic dysfunction.
On December 12th we hosted our latest ‘Facebook Live: Ask the Stem Cell Team’ event. This time around we really did mean team. We had a host of our Science Officers answering questions from friends and supporters of CIRM. We got a lot of questions and didn’t have enough time to address them all. So here’s answers to all the questions.
What are the obstacles to using partial cellular reprogramming to return people’s entire bodies to a youthful state.Paul Hartman. San Leandro, California
Dr. Kelly Shepard: Certainly, scientists have observed that various manipulations of cells, including reprogramming, partial reprogramming, de-differentiation and trans-differentiation, can restore or change properties of cells, and in some cases, these changes can reflect a more “youthful” state, such as having longer telomeres, better proliferative capacity, etc. However, some of these same rejuvenating properties, outside of their normal context, could be harmful or deadly, for example if a cell began to grow and divide when or where it shouldn’t, similar to cancer. For this reason, I believe the biggest obstacles to making this approach a reality are twofold: 1) our current, limited understanding of the nature of partially reprogrammed cells; and 2) our inability to control the fate of those cells that have been partially reprogrammed, especially if they are inside a living organism. Despite the challenges, I think there will be step wise advances where these types of approaches will be applied, starting with specific tissues. For example, CIRM has recently funded an approach that uses reprogramming to make “rejuvenated” versions of T cells for fighting lung cancer. There is also a lot of interest in using such approaches to restore the reparative capacity of aged muscle. Perhaps some successes in these more limited areas will be the basis for expanding to a broader use.
What’s going on with Stanford’s stem cell trials for stroke? I remember the first trial went really well In 2016 have not heard anything about since? Elvis Arnold
Dr. Lila Collins: Hi Elvis, this is an evolving story. I believe you are referring to SanBio’s phase 1/2a stroke trial, for which Stanford was a site. This trial looked at the safety and feasibility of SanBio’s donor or allogeneic stem cell product in chronic stroke patients who still had motor deficits from their strokes, even after completing physical therapy when natural recovery has stabilized. As you note, some of the treated subjects had promising motor recoveries.
SanBio has since completed a larger, randomized phase 2b trial in stroke, and they have released the high-level results in a press release. While the trial did not meet its primary endpoint of improving motor deficits in chronic stroke, SanBio conducted a very similar randomized trial in patients with stable motor deficits from chronic traumatic brain injury (TBI). In this trial, SanBio saw positive results on motor recovery with their product. In fact, this product is planned to move towards a conditional approval in Japan and has achieved expedited regulatory status in the US, termed RMAT, in TBI which means it could be available more quickly to patients if all goes well. SanBio plans to continue to investigate their product in stroke, so I would stay tuned as the work unfolds.
Also, since you mentioned Stanford, I should note that Dr Gary Steinberg, who was a clinical investigator in the SanBio trial you mentioned, will soon be conducting a trial with a different product that he is developing, neural progenitor cells, in chronic stroke. The therapy looks promising in preclinical models and we are hopeful it will perform well for patients in the clinic.
I am a stroke survivor will stem cell treatment able to restore my motor skills?Ruperto
Dr. Lila Collins:
Hi Ruperto. Restoring motor loss after stroke is a very active area of research. I’ll touch upon a few ongoing stem cell trials. I’d just like to please advise that you watch my colleague’s comments on stem cell clinics (these can be found towards the end of the blog) to be sure that any clinical research in which you participate is as safe as possible and regulated by FDA.
Back to stroke, I mentioned SanBio’s ongoing work to address motor skill loss in chronic stroke earlier. UK based Reneuron is also conducting a phase 2 trial, using a neural progenitor cell as a candidate therapy to help recover persistent motor disability after stroke (chronic). Dr Gary Steinberg at Stanford is also planning to conduct a clinical trial of a human embryonic stem cell-derived neuronal progenitor cell in stroke.
There is also promising work being sponsored by Athersys in acute stroke. Athersys published results from their randomized, double blinded placebo controlled Ph2 trial of their Multistem product in patients who had suffered a stroke within 24-48 hours. After intravenous delivery, the cells improved a composite measure of stroke recovery, including motor recovery. Rather than acting directly on the brain, Multistem seems to work by traveling to the spleen and reducing the inflammatory response to a stroke that can make the injury worse.
Athersys is currently recruiting a phase 3 trial of its Multistem product in acute stroke (within 1.5 days of the stroke). The trial has an accelerated FDA designation, called RMAT and a special protocol assessment. This means that if the trial is conducted as planned and it reaches the results agreed to with the FDA, the therapy could be cleared for marketing. Results from this trial should be available in about two years.
Questions from several hemorrhagic stroke survivors who say most clinical trials are for people with ischemic strokes. Could stem cells help hemorrhagic stroke patients as well?
Dr. Lila Collins:
Regarding hemorrhagic stroke, you are correct the bulk of cell therapies for stroke target ischemic stroke, perhaps because this accounts for the vast bulk of strokes, about 85%.
That said, hemorrhagic strokes are not rare and tend to be more deadly. These strokes are caused by bleeding into or around the brain which damages neurons. They can even increase pressure in the skull causing further damage. Because of this the immediate steps treating these strokes are aimed at addressing the initial bleeding insult and the blood in the brain.
While most therapies in development target ischemic stroke, successful therapies developed to repair neuronal damage or even some day replace lost neurons, could be beneficial after hemorrhagic stroke as well.
I had an Ischemic stroke in 2014, and my vision was also affected. Can stem cells possibly help with my vision issues. James Russell
Dr. Lila Collins:
Hi James. Vision loss from stroke is complex and the type of loss depends upon where the stroke occurred (in the actual eye, the optic nerve or to the other parts of the brain controlling they eye or interpreting vision). The results could be:
Visual loss from damage to the retina
You could have a normal eye with damage to the area of the brain that controls the eye’s movement
You could have damage to the part of the brain that interprets vision.
You can see that to address these various issues, we’d need different cell replacement approaches to repair the retina or the parts of the brain that were damaged.
Replacing lost neurons is an active effort that at the moment is still in the research stages. As you can imagine, this is complex because the neurons have to make just the right connections to be useful.
Is there any stem cell therapy for optical nerve damage? Deanna Rice
Dr. Ingrid Caras: There is currently no proven stem cell therapy to treat optical nerve damage, even though there are shady stem cell clinics offering treatments. However, there are some encouraging early gene therapy studies in mice using a virus called AAV to deliver growth factors that trigger regeneration of the damaged nerve. These studies suggest that it may be possible to restore at least some visual function in people blinded by optic nerve damage from glaucoma
I read an article about ReNeuron’s retinitis pigmentosa clinical trial update. In the article, it states: “The company’s treatment is a subretinal injection of human retinal progenitors — cells which have almost fully developed into photoreceptors, the light-sensing retinal cells that make vision possible.” My question is: If they can inject hRPC, why not fully developed photoreceptors?Leonard
Dr. Kelly Shepard: There is evidence from other studies, including from other tissue types such as blood, pancreas, heart and liver, that fully developed (mature) cell types tend not to engraft as well upon transplantation, that is the cells do not establish themselves and survive long term in their new environment. In contrast, it has been observed that cells in a slightly less “mature” state, such as those in the progenitor stage, are much more likely to establish themselves in a tissue, and then differentiate into more mature cell types over time. This question gets at the crux of a key issue for many new therapies, i.e. what is the best cell type to use, and the best timing to use it.
My question for the “Ask the Stem Cell Team” event is: When will jCyte publish their Phase IIb clinical trial results. Chris Allen
Dr. Ingrid Caras: The results will be available sometime in 2020.
I understand the hRPC cells are primarily neurotropic (rescue/halt cell death); however, the literature also says hRPC can become new photoreceptors. My questions are:Approximately what percentage develop into functioning photoreceptors? And what percentage of the injected hRPC are currently surviving?Leonard Furber, an RP Patient
Dr. Kelly Shepard: While we can address these questions in the lab and in animal models, until there is a clinical trial, it is not possible to truly recreate the environment and stresses that the cells will undergo once they are transplanted into a human, into the site where they are expected to survive and function. Thus, the true answer to this question may not be known until after clinical trials are performed and the results can be evaluated. Even then, it is not always possible to monitor the fate of cells after transplantation without removing tissues to analyze (which may not be feasible), or without being able to transplant labeled cells that can be readily traced.
Dr. Ingrid Caras – Although the cells have been shown to be capable of developing into photoreceptors, we don’t know if this actually happens when the cells are injected into a patient’s eye. The data so far suggest that the cells work predominantly by secreting growth factors that rescue damaged retinal cells or even reverse the damage. So one possible outcome is that the cells slow or prevent further deterioration of vision. But an additional possibility is that damaged retinal cells that are still alive but are not functioning properly may become healthy and functional again which could result in an improvement in vision.
What advances have been made using stem cells for the treatment of Type 2 Diabetes?Mary Rizzo
Dr. Ross Okamura: Type 2 Diabetes (T2D) is a disease where the body is unable to maintain normal glucose levels due to either resistance to insulin-regulated control of blood sugar or insufficient insulin production from pancreatic beta cells. The onset of disease has been associated with lifestyle influenced factors including body mass, stress, sleep apnea and physical activity, but it also appears to have a genetic component based upon its higher prevalence in certain populations.
Type 1 Diabetes (T1D) differs from T2D in that in T1D patients the pancreatic beta cells have been destroyed by the body’s immune system and the requirement for insulin therapy is absolute upon disease onset rather than gradually developing over time as in many T2D cases. Currently the only curative approach to alleviate the heavy burden of disease management in T1D has been donor pancreas or islet transplantation. However, the supply of donor tissue is small relative to the number of diabetic patients. Donor islet and pancreas transplants also require immune suppressive drugs to prevent allogenic immune rejection and the use of these drugs carry additional health concerns. However, for some patients with T1D, especially those who may develop potentially fatal hypoglycemia, immune suppression is worth the risk.
To address the issue of supply, there has been significant activity in stem cell research to produce insulin secreting beta cells from pluripotent stem cells and recent clinical data from Viacyte’s CIRM funded trial indicates that implanted allogeneic human stem cell derived cells in T1D patients can produce circulating c-peptide, a biomarker for insulin. While the trial is not designed specifically to cure insulin-dependent T2D patients, the ability to produce and successfully engraft stem cell-derived beta cells would be able to help all insulin-dependent diabetic patients.
It’s also worth noting that there is a sound scientific reason to clinically test a patient-derived pluripotent stem cell-based insulin-producing cells in insulin-dependent T2D diabetic patients; the cells in this case could be evaluated for their ability to cure diabetes in the absence of needing to prevent both allogeneic and autoimmune responses.
SPINAL CORD INJURY
Is there any news on clinical trials for spinal cord injury? Le Ly
Kevin McCormack: The clinical trial CIRM was funding, with Asterias (now part of a bigger company called Lineage Cell Therapeutics, is now completed and the results were quite encouraging. In a news release from November of 2019 Brian Culley, CEO of Lineage Cell Therapeutics, described the results this way.
“We remain extremely excited about the potential for OPC1 (the name of the therapy used) to provide enhanced motor recovery to patients with spinal cord injuries. We are not aware of any other investigative therapy for SCI (spinal cord injury) which has reported as encouraging clinical outcomes as OPC1, particularly with continued improvement beyond 1 year. Overall gains in motor function for the population assessed to date have continued, with Year 2 assessments measuring the same or higher than at Year 1. For example, 5 out of 6 Cohort 2 patients have recovered two or more motor levels on at least one side as of their Year 2 visit whereas 4 of 6 patients in this group had recovered two motor levels as of their Year 1 visit. To put these improvements into perspective, a one motor level gain means the ability to move one’s arm, which contributes to the ability to feed and clothe oneself or lift and transfer oneself from a wheelchair. These are tremendously meaningful improvements to quality of life and independence. Just as importantly, the overall safety of OPC1 has remained excellent and has been maintained 2 years following administration, as measured by MRI’s in patients who have had their Year 2 follow-up visits to date. We look forward to providing further updates on clinical data from SCiStar as patients continue to come in for their scheduled follow up visits.”
Lineage Cell Therapeutics plans to meet with the FDA in 2020 to discuss possible next steps for this therapy.
In the meantime the only other clinical trial I know that is still recruiting is one run by a company called Neuralstem. Here is a link to information about that trial on the www.clinicaltrials.gov website.
Now that the Brainstorm ALS trial is finished looking for new patients do you have any idea how it’s going and when can we expect to see results? Angela Harrison Johnson
Dr. Ingrid Caras: The treated patients have to be followed for a period of time to assess how the therapy is working and then the data will need to be analyzed. So we will not expect to see the results probably for another year or two.
Are there treatments for autism or fragile x using stem cells? Magda Sedarous
Dr. Kelly Shepard: Autism and disorders on the autism spectrum represent a collection of many different disorders that share some common features, yet have different causes and manifestations, much of which we still do not understand. Knowing the origin of a disorder and how it affects cells and systems is the first step to developing new therapies. CIRM held a workshop on Autism in 2009 to brainstorm potential ways that stem cell research could have an impact. A major recommendation was to exploit stem cells and new technological advances to create cells and tissues, such as neurons, in the lab from autistic individuals that could then be studied in great detail. CIRM followed this recommendation and funded several early-stage awards to investigate the basis of autism, including Rett Syndrome, Fragile X, Timothy Syndrome, and other spectrum disorders. While these newer investigations have not yet led to therapies that can be tested in humans, this remains an active area of investigation. Outside of CIRM funding, we are aware of more mature studies exploring the effects of umbilical cord blood or other specific stem cell types in treating autism, such as an ongoing clinical trial conducted at Duke University.
What is happening with Parkinson’s research? Hanifa Gaphoor
Dr. Kent Fitzgerald: Parkinson’s disease certainly has a significant amount of ongoing work in the regenerative medicine and stem cell research.
The nature of cell loss in the brain, specifically the dopaminergic cells responsible for regulating the movement, has long been considered a good candidate for cell replacement therapy.
This is largely due to the hypothesis that restoring function to these cells would reverse Parkinson’s symptoms. This makes a lot of sense as front line therapy for the disease for many years has been dopamine replacement through L-dopa pills etc. Unfortunately, over time replacing dopamine through a pill loses its benefit, whereas replacing or fixing the cells themselves should be a more permanent fix.
Because a specific population of cells in one part of the brain are lost in the disease, multiple labs and clinicians have sought to replace or augment these cells by transplantation of “new” functional cells able to restore function to the area an theoretically restore voluntary motor control to patients with Parkinson’s disease.
Early clinical research showed some promise, however also yielded mixed results, using fetal tissue transplanted into the brains of Parkinson’s patients. As it turns out, the cell types required to restore movement and avoid side effects are somewhat nuanced. The field has moved away from fetal tissue and is currently pursuing the use of multiple stem cell types that are driven to what is believed to be the correct subtype of cell to repopulate the lost cells in the patient.
One project CIRM sponsored in this area with Jeanne Loring sought to develop a cell replacement therapy using stem cells from the patients themselves that have been reprogrammed into the kinds of cell damaged by Parkinson’s. This type of approach may ultimately avoid issues with the cells avoiding rejection by the immune system as can be seen with other types of transplants (i.e. liver, kidney, heart etc).
Still, others are using cutting edge gene therapy technology, like the clinical phase project CIRM is sponsoring with Krystof Bankiewicz to investigate the delivery of a gene (GDNF) to the brain that may help to restore the activity of neurons in the Parkinson’s brain that are no longer working as they should.
The bulk of the work in the field of PD at the present remains centered on replacing or restoring the dopamine producing population of cells in the brain that are affected in disease.
Any plans for Huntington’s?Nikhat Kuchiki
Dr. Lisa Kadyk: The good news is that there are now several new therapeutic approaches to Huntington’s Disease that are at various stages of preclinical and clinical development, including some that are CIRM funded. One CIRM-funded program led by Dr. Leslie Thompson at UC Irvine is developing a cell-based therapeutic that consists of neural stem cells that have been manufactured from embryonic stem cells. When these cells are injected into the brain of a mouse that has a Huntington’s Disease mutation, the cells engraft and begin to differentiate into new neurons. Improvements are seen in the behavioral and electrophysiological deficits in these mutant mice, suggesting that similar improvements might be seen in people with the disease. Currently, CIRM is funding Dr. Thompson and her team to carry out rigorous safety studies in animals using these cells, in preparation for submitting an application to the FDA to test the therapy in human patients in a clinical trial.
There are other, non-cell-based therapies also being tested in clinical trials now, using anti-sense oligonucleotides (Ionis, Takeda) to lower the expression of the Huntington protein. Another HTT-lowering approach is similar – but uses miRNAs to lower HTT levels (UniQure,Voyager)
TRAUMATIC BRAIN INJURY (TBI)
My 2.5 year old son recently suffered a hypoxic brain injury resulting in motor and speech disabilities. There are several clinical trials underway for TBI in adults. My questions are:
Will the results be scalable to pediatric use and how long do you think it would take before it is available to children?
I’m wondering why the current trials have chosen to go the route of intracranial injections as opposed to something slightly less invasive like an intrathecal injection?
Is there a time window period in which stem cells should be administered by, after which the administration is deemed not effective?
Dr. Kelly Shepard: TBI and other injuries of the nervous system are characterized by a lot of inflammation at the time of injury, which is thought to interfere with the healing process- and thus some approaches are intended to be delivered after that inflammation subsides. However, we are aware of approaches that intend to deliver a therapy to a chronic injury, or one that has occurred previously. Thus, the answer to this question may depend on how the intended therapy is supposed to work. For example, is the idea to grow new neurons, or is it to promote the survival of neurons of other cells that were spared by the injury? Is the therapy intended to address a specific symptom, such as seizures? Is the therapy intended to “fill a gap” left behind after inflammation subsides, which might not restore all function but might ameliorate certain symptoms.? There is still a lot we don’t understand about the brain and the highly sophisticated network of connections that cannot be reversed by only replacing neurons, or only reducing inflammation, etc. However, if trials are well designed, they should yield useful information even if the therapy is not as effective as hoped, and this information will pave the way to newer approaches and our technology and understanding evolves.
We have had a doctor recommending administering just the growth factors derived from MSC stem cells. Does the science work that way? Is it possible to isolate the growth factors and boost the endogenous growth factors by injecting allogenic growth factors?
Dr. Stephen Lin: Several groups have published studies on the therapeutic effects in non-human animal models of using nutrient media from MSC cultures that contain secreted factors, or extracellular vesicles from cells called exosomes that carry protein or nucleic acid factors. Scientifically it is possible to isolate the factors that are responsible for the therapeutic effect, although to date no specific factor or combination of factors have been identified to mimic the effects of the undefined mixtures in the media and exosomes. At present no regulatory approved clinical therapy has been developed using this approach.
PREDATORY STEM CELL CLINICS
What practical measures are being taken to address unethical practitioners whose bad surgeries are giving stem cell advances a bad reputation and are making forward research difficult?Kathy Jean Schultz
Dr. Geoff Lomax: Terrific question! I have been doing quite a bit research into the history of this issue of unethical practitioners and I found an 1842 reference to “quack medicines.” Clearly this is nothing new. In that day, the author appealed to make society “acquainted with the facts.”
In California, we have taken steps to (1) acquaint patients with the facts about stem cell treatments and (2) advance FDA authorized treatments for unmet medical needs.
First, CIRM work with Senator Hernandez in 2017 to write a law the requires provides to disclose to patient that a stem cell therapy has not been approved by the Food and Drug administration.
We continue to work with the State Legislature and Medical Board of California to build on policies that require accurate disclosure of the facts to patients.
Second, our clinical trial network the — Alpha Stem Cell Clinics – have supported over 100 FDA-authorized clinical trials to advance responsible clinical research for unmet medical needs.
I’m curious if adipose stem cell being used at clinics at various places in the country is helpful or beneficial?Cheri Hicks
Adipose tissue has been widely used particularly in plastic and reconstructive surgery. Many practitioners suggest adipose cells are beneficial in this context. With regard to regenerative medicine and / or the ability to treat disease and injury, I am not aware of any large randomized clinical trials that demonstrate the safety and efficacy of adipose-derived stem cells used in accordance with FDA guidelines.
I went to a “Luncheon about Stem Cell Injections”. It sounded promising. I went thru with it and got the injections because I was desperate from my knee pain. The price of stem cell injections was $3500 per knee injection. All went well. I have had no complications, but haven’t noticed any real major improvement, and here I am a year later. My questions are:
1) I wonder on where the typical injection cells are coming from?
2) I wonder what is the actual cost of the cells?
3) What kind of results are people getting from all these “pop up” clinics or established clinics that are adding this to there list of offerings?
Dr. Geoff Lomax: You raise a number of questions and point here; they are all very good and it’s is hard to give a comprehensive response to each one, but here is my reaction:
There are many practitioners in the field of orthopedics who sincerely believe in the potential of cell-based treatments to treat injury / pain
Most of the evidence presented is case reports that individuals have benefited
The challenge we face is not know the exact type of injury and cell treatments used.
Well controlled clinical trials would really help us understand for what cells (or cell products) and for what injury would be helpful
Prices of $3000 to $5000 are not uncommon, and like other forms of private medicine there is often a considerable mark-up in relation to cost of goods.
You are correct that there have not been reports of serious injury for knee injections
However the effectiveness is not clear while simultaneously millions of people have been aided by knee replacements.
Do stem cells have benefits for patients going through chemotherapy and radiation therapy?Ruperto
Dr. Kelly Shepard: The idea that a stem cell therapy could help address effects of chemotherapy or radiation is being and has been pursued by several investigators over the years, including some with CIRM support. Towards the earlier stages, people are looking at the ability of different stem cell-derived neural cell preparations to replace or restore function of certain brain cells that are damaged by the effects of chemotherapy or radiation. In a completely different type of approach, a group at City of Hope is exploring whether a bone marrow transplant with specially modified stem cells can provide a protective effect against the chemotherapy that is used to treat a form of brain cancer, glioblastoma. This study is in the final stage of development that, if all goes well, culminates with application to the FDA to allow initiation of a clinical trial to test in people.
Dr. Ingrid Caras: That’s an interesting and valid question. There is a Phase 1 trial ongoing that is evaluating a novel type of stem/progenitor cell from the umbilical cord of healthy deliveries. In animal studies, these cells have been shown to reduce the toxic effects of chemotherapy and radiation and to speed up recovery. These cells are now being tested in a First-in-human clinical trial in patients who are undergoing high-dose chemotherapy to treat their disease.
There is a researcher at Stanford, Michelle Monje, who is investigating that the role of damage to stem cells in the cognitive problems that sometimes arise after chemo- and radiation therapy (“chemobrain”). It appears that damage to stem cells in the brain, especially those responsible for producing oligodendrocytes, contributes to chemobrain. In CIRM-funded work, Dr. Monje has identified small molecules that may help prevent or ameliorate the symptoms of chemobrain.
Is it possible to use a technique developed to fight one disease to also fight another? For instance, the bubble baby disease, which has cured (I think) more than 50 children, may also help fight sickle cell anemia? Don Reed.
Dr. Lisa Kadyk: Hi Don. Yes, the same general technique can often be applied to more than one disease, although it needs to be “customized” for each disease. In the example you cite, the technique is an “autologous gene-modified bone marrow transplant” – meaning the cells come from the patient themselves. This technique is relevant for single gene mutations that cause diseases of the blood (hematopoietic) system. For example, in the case of “bubble baby” diseases, a single mutation can cause failure of immune cell development, leaving the child unable to fight infections, hence the need to have them live in a sterile “bubble”. To cure that disease, blood stem cells, which normally reside in the bone marrow, are collected from the patient and then a normal version of the defective gene is introduced into the cells, where it is incorporated into the chromosomes. Then, the corrected stem cells are transplanted back into the patient’s body, where they can repopulate the blood system with cells expressing the normal copy of the gene, thus curing the disease.
A similar approach could be used to treat sickle cell disease, since it is also caused by a single gene mutation in a gene (beta hemoglobin) that is expressed in blood cells. The same technique would be used as I described for bubble baby disease but would differ in the gene that is introduced into the patient’s blood stem cells.
Is there any concern that CIRM’s lack of support in basic research will hamper the amount of new approaches that can reach clinical stages? Jason
Dr. Kelly Shepard: CIRM always has and continues to believe that basic research is vital to the field of regenerative medicine. Over the past 10 years CIRM has invested $904 million in “discovery stage/basic research”, and about $215 million in training grants that supported graduate students, post docs, clinical fellows, undergraduate, masters and high school students performing basic stem cell research. In the past couple of years, with only a limited amount of funds remaining, CIRM made a decision to invest most of the remaining funds into later stage projects, to support them through the difficult transition from bench to bedside. However, even now, CIRM continues to sponsor some basic research through its Bridges and SPARK Training Grant programs, where undergraduate, masters and even high school students are conducting stem cell research in world class stem cell laboratories, many of which are the same laboratories that were supported through CIRM basic research grants over the past 10 years. While basic stem cell research continues to receive a substantial level of support from the NIH ($1.8 billion in 2018, comprehensively on stem cell projects) and other funders, CIRM believes continued support for basic research, especially in key areas of stem cell research and vital opportunities, will always be important for discovering and developing new treatments.
What is the future of the use of crispr cas9 in clinical trials in california/globally. Art Venegas
Dr. Kelly Shepard: CRISPR/Cas9 is a powerful gene editing tool. In only a few years, CRISPR/Cas9 technology has taken the field by storm and there are already a few CRISPR/Cas9 based treatments being tested in clinical trials in the US. There are also several new treatments that are at the IND enabling stage of development, which is the final testing stage required by the FDA before a clinical trial can begin. Most of these clinical trials involving CRISPR go through an “ex vivo” approach, taking cells from the patient with a disease causing gene, correcting the gene in the laboratory using CRISPR, and reintroducing the cells carrying the corrected gene back into the patient for treatment. Sickle cell disease is a prime example of a therapy being developed using this strategy and CIRM funds two projects that are preparing for clinical trials with this approach. CRISPR is also being used to develop the next generation of cancer T-cell therapies (e.g. CAR-T), where T-cells – a vital part of our immune system – are modified to target and destroy cancer cell populations. Using CRISPR to edit cells directly in patients “in vivo” (inside the body) is far less common currently but is also being developed. It is important to note that any FDA sanctioned “in vivo” CRISPR clinical trial in people will only modify organ-specific cells where the benefits cannot be passed on to subsequent generations. There is a ban on funding for what are called germ line cells, where any changes could be passed down to future generations.
CIRM is currently supporting multiple CRISPR/Cas9 gene editing projects in California from the discovery or most basic stage of research, through the later stages before applying to test the technique in people in a clinical trial.
While the field is new – if early safety signals from the pioneering trials are good, we might expect a number of new CRISPR-based approaches to enter clinical testing over the next few years. The first of these will will likely be in the areas of bone marrow transplant to correct certain blood/immune or metabolic diseases, and cancer immunotherapies, as these types of approaches are the best studied and furthest along in the pipeline.
Explain the differences between gene therapy and stem cell therapy?Renee Konkol
Dr. Stephen Lin: Gene therapy is the direct modification of cells in a patient to treat a disease. Most gene therapies use modified, harmless viruses to deliver the gene into the patient. Gene therapy has recently seen many success in the clinic, with the first FDA approved therapy for a gene induced form of blindness in 2017 and other approvals for genetic forms of smooth muscle atrophy and amyloidosis.
Stem cell therapy is the introduction of stem cells into patients to treat a disease, usually with the purpose of replacing damaged or defective cells that contribute to the disease. Stem cell therapies can be derived from pluripotent cells that have the potential to turn into any cell in the body and are directed towards a specific organ lineage for the therapy. Stem cell therapies can also be derived from other cells, called progenitors, that have the ability to turn into a limited number of other cells in the body. for example hematopoietic or blood stem cells (HSCs), which are found in bone marrow, can turn into other cells of the blood system including B-cells and T-cells: while mesenchymal stem cells (MSCs), which are usually found in fat tissue, can turn into bone, cartilage, and fat cells. The source of these cells can be from the patient’s own body (autologous) or from another person (allogeneic).
Gene therapy is often used in combination with cell therapies when cells are taken from the patient and, in the lab, modified genetically to correct the mutation or to insert a correct form of the defective gene, before being returned to patients. Often referred to as “ex vivo gene therapy” – because the changes are made outside the patient’s body – these therapies include Chimeric Antigen Receptor T (CAR-T) cells for cancer therapy and gene modified HSCs to treat blood disorders such as severe combined immunodeficiency and sickle cell disease. This is an exciting area that has significantly improved and even cured many people already.
Currently, how can the outcome of CIRM stem cell medicine projects and clinical trials be soundly interpreted when their stem cell-specific doses are not known?James L. Sherley, M.D., Ph.D., Director. Asymmetrex, LLC
Dr. Stephen Lin: Stem cell therapies that receive approval to conduct clinical trials must submit a package of data to the FDA that includes studies that demonstrate their effectiveness, usually in animal models of the disease that the cell therapy is targeting. Those studies have data on the dose of the cell therapy that creates the therapeutic effect, which is used to estimate cell doses for the clinical trial. CIRM funds discovery and translational stage awards to conduct these types of studies to prepare cell therapies for clinical trials. The clinical trial is also often designed to test multiple doses of the cell therapy to determine the one that has the best therapeutic effect. Dosing can be very challenging with cell therapies because of issues including survival, engraftment, and immune rejection, but CIRM supports studies designed to provide data to give the best estimate possible.
Is there any research on using stem cells to increase the length of long bones in people?” For example, injecting stem cells into the growth plates to see if the cells can be used to lengthen limbs.Sajid
Dr. Kelly Shepard: There is quite a lot of ongoing research seeking ways to repair bones with stem cell based approaches, which is not the same but somewhat related. Much of this is geared towards repairing the types of bone injuries that do not heal well naturally on their own (large gaps, dead bone lesions, degenerative bone conditions). Also, a lot of this research involves engineering bone tissues in the lab and introducing the engineered tissue into a bone lesion that need be repaired. What occurs naturally at the growth plate is a complex interaction between many different cell types, much of which we do not fully understand. We do not fully understand how to use the cells that are used to engineer bone tissue in the lab. However, a group at Stanford, with some CIRM support, recently discovered a “skeletal stem cell” that exists naturally at the ends of human bones and at sites of fracture. These are quite different than MSCs and offer a new path to be explored for repairing and generating bone.
Cystic fibrosis is a disorder that mostly affects the lungs. It is caused by a mutation in a gene called cystic fibrosis transmembrane conductance regulator (CFTR). As a result of this mutation, cells that produce mucus (a slimy substance like the one in your nose) secrete a thicker-than-normal mucus that can create blockages in the lungs and digestive system. In the lungs, this thicker mucus is a perfect breeding ground for bacteria, leading to more chronic lung infections in those with cystic fibrosis.
However, some people with cystic fibrosis don’t develop lung infections as early or as often as others with the disorder. Thanks to a CIRM funded study, Dr. Kelly Frazer and her team at the UC San Diego School of Medicine have discovered why this might happen.
Before we get into that, we need to dive a bit deeper into cystic fibrosis and what causes this thicker-than normal mucus. In healthy people, CFTR is embedded in the membrane of most cells, where it forms a channel that allows chloride – a component of salt – to travel through. This flow ensures that cells have the right balance of salt and water. In people with cystic fibrosis, the CFTR mutation means that the channel doesn’t work as well, the flow of water is blocked resulting in more thick and sticky mucus. There are medications that can help boost CFTR, but they are very expensive and don’t work for everyone.
Dr. Frazer and her team discovered that a gene, called RNF5, also prevents CFTR from functioning well. People with cystic fibrosis who have lower levels of RNF5 have channels that function better, with less mucus build up, compared to people with higher levels of RNF5. This could potentially explain why some with cystic fibrosis get more chronic lung infections compared to others with the condition.
In a press release by UC San Diego School of Medicine, Dr. Frazer talks about how RNF5 could play a role in treating patients.
“The cystic fibrosis field is trying to figure out what are the modifiers across the genome that increase or decrease the probability that an individual patient will respond to these expensive drugs. RNF5 may be one of these modifier genes.”
In the same press release, Dr. Matteo D’Antonio, a project scientist in Dr. Frazer’s lab, talks about how these findings could result in more personalized treatments for people with cystic fibrosis.
“This study uncovered a new aspect of cystic fibrosis — one that could lead to new drug design and development, and allow clinicians to better tailor treatments.”
One of the hottest areas in cancer research right now is the use of CAR-T treatments. These use the patient’s own re-engineered immune system cells to target and kill the tumor. But the thing that makes it so appealing – using the patient’s own cells – also makes it really complicated and expensive. Creating a custom-made therapy from each patient’s own cells takes time and costs a lot of money. But now a new approach could change that.
Fate Therapeutics has developed an off-the-shelf therapy (thanks to CIRM funding) that could, theoretically, be stored at hospitals and clinics around the country and used whenever it’s needed for anyone who needs it.
Equally impressive is that 42 days after being treated with FT516, the man showed no signs of leukemia in either his bone marrow or blood.
FT516 is designed to provide a one-two combination attack on cancer. It’s made up of the wonderfully named natural killer (NK) cells, which are a critical part of our immune system defenses against cancer. These NK cells are created by using the iPSC process and have been genetically modified to express a protein that boosts their cancer-killing abilities.
Because these cells are manufactured they can, if effective, be produced in large numbers and stored for whenever needed. That would not only dramatically reduce costs but also make them more widely available when they are needed.
This is only one patient and the follow-up is still relatively short. Even so, the results are encouraging and certainly give hope that Fate is on to something big. We’ll be keeping track and let you know how things progress.