Stanford scientist uses CRISPR-Cas9 and stem cells to develop potential “bubble baby” therapy

Dr. Matthew Porteus, professor of pediatrics at Stanford University.
Photo courtesy of Stanford Medicine.

Our immune system is an important and essential part of everyday life. It is crucial for fighting off colds and, with the help of vaccinations, gives us immunity to potentially lethal diseases. Unfortunately, for some infants, this innate bodily defense mechanism is not present or is severely lacking in function.

This condition is known as severe combined immunodeficiency (SCID), commonly nicknamed “bubble baby” disease because of the sterile plastic bubble these infants used to be placed in to prevent exposure to bacteria, viruses, and fungi that can cause infection. There are several forms of SCID, one of which involves a single genetic mutation on the X chromosome and is known as SCID-X1

Many infants with SCID-X1 develop chronic diarrhea, a fungal infection called thrush, and skin rashes. Additionally, these infants grow slowly in comparison to other children. Without treatment, many infants with SCID-X1 do not live beyond infancy.

SCID-X1 occurs almost predominantly in males since they only carry one X chromosome, with at least 1 in 50,000 baby boys born with this condition. Since females carry two X chromosomes, one inherited from each parent, they are unlikely to inherit two X chromosomes with the mutation present since it would require the father to have SCID-X1.

What if there was a way to address this condition by correcting the single gene mutation? Dr. Matthew Porteus at Stanford University is leading a study that has developed an approach to treat SCID-X1 that utilizes this concept.

By using CRISPR-Cas9 technology, which we have discussed in detail in a previous blog post, it is possible to delete a problematic gene and insert a corrected gene. Dr. Porteus and his team are using CRISPR-Cas9 to edit blood stem cells, which give rise to immune cells, which are the foundation of the body’s defense mechanism. In a study published in Nature, Dr. Porteus and his team have demonstrated proof of concept of this approach in an animal model.

The Stanford team was able to take blood stem cells from six infants with SCID-X1 and corrected them with CRISPR-Cas9. These corrected stem cells were then introduced into mice modeled to have SCID-X1. It was found that these mice were not only able to make immune cells, but many of the edited stem cells maintained their ability to continuously create new blood cells.

In a press release, Dr. Mara Pavel-Dinu, a member of the research team, said:

“To our knowledge, it’s the first time that human SCID-X1 cells edited with CRISPR-Cas9 have been successfully used to make human immune cells in an animal model.”

CIRM has previously awarded Dr. Porteus with a preclinical development award aimed at developing gene correction therapy for blood stem cells for SCID-X1. In addition to this, CIRM has funded two other projects conducted by Dr. Porteus related to CRISPR-Cas9. One of these projects used CRISPR-Cas 9 to develop a treatment for chronic sinusitis due to cystic fibrosis and the second project used the technology to develop an approach for treating sickle cell disease.

CIRM has also funded four clinical trials related to SCID. Two of these trials are related to SCID-X1, one being conducted at St. Jude Children’s Research Hospital and the other at Stanford University. The third trial is related to a different form of SCID known as ADA-SCID and is being conducted at UCLA in partnership with Orchard Therapeutics. Finally, the last of the four trials is related to an additional form of SCID known as ART-SCID and is being conducted at UCSF.

First patient treated for colon cancer using reprogrammed adult cells

Dr. Sandip Patel (left) and Dr. Dan Kaufman (center) of UC San Diego School of Medicine enjoy a light-hearted moment before Derek Ruff (right) receives the first treatment for cancer using human-induced pluripotent stem cells (hiPSCs). Photo courtesy of UC San Diego Health.

For patients battling cancer for the first time, it can be quite a draining and grueling process. Many treatments are successful and patients go into remission. However, there are instances where the cancer returns in a much more aggressive form. Unfortunately, this was the case for Derek Ruff.

After being in remission for ten years, Derek’s cancer returned as Stage IV colon cancer, meaning that the cancer has spread from the colon to distant organs and tissues. According to statistics from Fight Colorectal Cancer, colorectal cancer is the 2nd leading cause of cancer death among men and women combined in the United States. 1 in 20 people will be diagnosed with colorectal cancer in their lifetime and it is estimated that there will be 140,250 new cases in 2019 alone. Fortunately, Derek was able to enroll in a groundbreaking clinical trial to combat his cancer.

In February 2019, as part of a clinical trial at the Moores Cancer Center at UC San Diego Health in collaboration with Fate Therapeutics, Derek became the first patient in the world to be treated for cancer with human-induced pluripotent stem cells (hiPSCs). hiPSCs are human adult cells, such as those found on the skin, that are reprogrammed into stem cells with the ability to turn into virtually any kind of cell. In this trial, hiPSCs were reprogrammed into natural killer (NK) cells, which are specialized immune cells that are very effective at killing cancer cells, and are aimed at treating Derek’s colon cancer.

A video clip from ABC 10 News San Diego features an interview with Derek and the groundbreaking work being done.

In a public release, Dr. Dan Kaufman, one of the lead investigators of this trial at UC San Diego School of Medicine, was quoted as saying,

“This is a landmark accomplishment for the field of stem cell-based medicine and cancer immunotherapy. This clinical trial represents the first use of cells produced from human induced pluripotent stem cells to better treat and fight cancer.”

In the past, CIRM has given Dr. Kaufman funding related to the development of NK cells. One was a $1.9 million grant for developing a different type of NK cell from hiPSCs, which could also potentially treat patients with lethal cancers. The second grant was a $4.7 million grant for developing NK cells from human embryonic stem cells (hESCs) to potentially treat patients with acute myelogenous leukemia (AML).

In the public release, Dr. Kaufman is also quoted as saying,

“This is a culmination of 15 years of work. My lab was the first to produce natural killer cells from human pluripotent stem cells. Together with Fate Therapeutics, we’ve been able to show in preclinical research that this new strategy to produce pluripotent stem cell-derived natural killer cells can effectively kill cancer cells in cell culture and in mouse models.”

CRISPR-Cas9 101: an overview and the role it plays in developing therapies

Illustration courtesy of TED website

There has been a lot of conversation surrounding CRISPR-Cas9 in these recent months as well as many sensational news stories. Some of these stories highlight the promise this technology holds, while others emphasize a word of caution. But what exactly does this technology do and how does it work? Here is a breakdown that will help you better understand.

To start off, CRISPR is a naturally occurring process found in bacteria used as an immune system to defend against viruses. CRISPR simply put, are strands of DNA segments that contain repeating patterns. There are “scissor like” CRISPR proteins that have the ability to cut DNA segments. When a copy of a virus enters the bacteria, these “scissor like” proteins cut a segment of DNA from the virus and insert it into CRISPR. A copy of the viral DNA is made and another “attack” protein known as Cas9 attaches to it. By binding to the viral copy, Cas9 is able to sense that virus. When the same virus tries to enter the bacteria, Cas9 is able to seek and destroy it.

You can view a more detailed video explaining this concept below.

Many scientists analyzed this process in detail and it was eventually discovered that this CRISPR-Cas9 complex could be used to removed unwanted genes and insert a corrected copy, revolutionizing the way that we view the approach towards treating a wide variety of genetic diseases.

In fact, researchers at the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center and the University of Massachusetts Medical School have developed a strategy using this complex to treat two inherited, lethal blood disorders, sickle cell disease (SCD) and beta thalassemia. Both of these diseases involve a mutation that effects production of red blood cells, which are produced by blood stem cells. In beta-thalassemia, the mutation prevent red blood cells from being able to carry enough oxygen, leading to anemia. In SCD, the mutations cause red blood cells to take on a “sickle” shape which can block blood vessels.

By using CRISPR-Cas9 to insert a corrected copy of the gene into a patient’s own blood stem cells, this team demonstrated that functional red blood cells can then be produced. These results pay the way for other blood disorders as well.

In a press release , Dr. Daniel Bauer, an attending physician with Dana-Farber and a senior author on both of these studies stated that,

“Combining gene editing with an autologous stem-cell transplant could be a therapy for sickle-cell disease, beta-thalassemia and other blood disorders.”

In a separate study, scientists at University of Massachusetts Medical School have developed a strategy that could be used to treat genetic disorders associated with unintentional repeats or copies of small DNA segments. These problematic small segments of DNA are called microduplications and cause as many as 143 different diseases, including limb-girdle muscular dystrophy, Hermansky-Pudlak syndrome, and Tay-Sachs.

Because these are issues caused by repeats or copies of small DNA segments, the CRISPR-Cas9 complex can be used to remove microduplications without having to insert any additional genetic material.

Dr. Scot A. Wolfe, a co-investigator of this study, stated that,

“It’s like hitting the reset button. We don’t have to add any corrective genetic material, instead the cell stitches the DNA back together minus the duplication. It’s a shortcut for gene correction with potential therapeutic appeal.”

Although there has been a lot progress made with this technology, there are still concerns that need to be addressed. An article in Science mentions how two studies have shown that CRISPR can still make unintended changes to DNA, which can be potentially dangerous. In the article, Dr. Jin-Soo Kim, a CRISPR researcher at Seoul National University is quoted as saying,

“It is now important to determine which component is responsible for the collateral mutations and how to reduce or avoid them.”

Overall, CRISPR-Cas9 has revolutionized the approach of precision medicine. A wide variety of diseases are caused by small, unexpected segments of DNA. By applying this approach found in bacteria to humans, we have uncovered a way to correct these segments at the microscopic level. However, there is still much that needs to be learned and perfected before it can be utilized in patients.

Old cells need not apply: how a stem cell’s age can impact potential treatments

Getting older is a normal, at times existential, part of life. The outward changes are abundant and noticeable: thinning of the hair, greying of the hair, and added lines to the face. There are also changes that happen that are not so abundantly clear in terms of outward appearance: slowing of healing time for bone fractures and a gradual loss of bodily function. The process of aging poses one very fundamental question — Could understanding how stem cells age lead to a greater understanding of how diseases develop? More importantly, could it guide the approach towards developing potential treatments? Two different studies highlight the importance of evaluating and understanding the process of aging in stem cells.

The first study, led by Dr. Michael Fehlings, looked at the impact of donor age in relation to stem cell therapies for spinal cord injuries (SCI). Dr. Fehlings, with a team of investigators from the University of Toronto and Krembil Research Institute, University Health Network, used an adult rat model to look at how cells derived from young vs. old stem cells affected tissue regeneration and recovery after a spinal cord injury.

Some rats with a SCI received cells derived from stem cells in the umbilical cord blood, which are considered “young” stem cells. The other rats with a SCI received cells derived from stem cells in the bone marrow, which are considered “old” stem cells. The results showed, ten weeks after treatment, that rats given the “young” stem cells exhibited a better recovery in comparison to those given the “old” stem cells.

In a press release, Dr. Fehlings stated that,

“Together, this minimally invasive and effective approach to cell therapy has significant implications on the treatment of traumatic cervical SCI and other central nervous system injuries. These results can help to optimize cell treatment strategies for eventual use in humans.”

The full results to this study were published in Stem Cells Translational Medicine.

The second, separate study, conducted by Dr. Stephen Crocker at UConn Health, looks at brain stem cells in people with multiple sclerosis (MS), a neurodegenerative disease caused by the inflammation and destruction of the insulation around the nerves, also known as myelin. Problems with insulation around the nerves can prevent or complicate the electrical signals sent from the brain to the body, which can lead to problems with walking or other bodily movements.

Drawing of a healthy nerve cell with insulation (left) and one damaged by multiple sclerosis (right). Image courtesy of Shutterstock

Dr. Crocker and his team found that brain stem cells in patients with MS look much older when compared to the brain stem cells of a healthy person around the same age. Not only did these brain stem cells look older, but they also acted much older in comparison to their healthy counterparts. It was also discovered that the brain stem cells of MS patients were producing a protein that prevented the development of insulation around the nerves. What is more remarkable is that Dr. Crocker and his team demonstrated that when this protein is blocked, the insulation around the nerves develops normally again.

In a press release, Dr. Valentina Fossati, a neurologist at the New York Stem Cell Foundation who evaluated these brain stem cells, stated that,

“We are excited that the study of human stem cells in a dish led to the discovery of a new disease mechanism that could be targeted in much-needed therapeutics for progressive MS patients.”

The complete study was published in the Proceedings of the National Academy of Sciences (PNAS).

Organoids revolutionize approach to studying a variety of diseases

Organoids

There are limitations to studying cells under a microscope. To understand some of the more complex processes, it is critical to see how these cells behave in an environment that is similar to conditions in the body. The production of organoids has revolutionized this approach.

Organoids are three-dimensional structures derived from stem cells that have similar characteristics of an actual organ. There have been several studies recently published that have used this approach to understand a wide scope of different areas.

In one such instance, researchers at The University of Cambridge were able to grow a “mini-brain” from human stem cells. To demonstrate that this organoid had functional capabilities similar to that of an actual brain, the researchers hooked it up to a mouse spinal cord and surrounding muscle. What they found was remarkable– the “mini-brain” sent electrial signals to the spinal cord that made the surrounding muscles twitch. This model could pave the way for studying neurodegenerative diseases such as spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS).

Spinal muscular atrophy

Speaking of SMA, researchers in Singapore have used organoids to come up with some findings that might be able to help people battling the condition.

SMA is a neurodegenerative disease caused by a protein deficiency that results in nerve degeneration, paralysis and even premature death. The fact that it mainly affects children makes it even worse. Not much is known how SMA develops and even less how to treat or prevent it.

That’s where the research from the A*STAR’s Institute of Molecular and Cell Biology (IMCB) comes in. Using the iPSC method they turned tissue samples from healthy people and people with SMA into spinal organoids.

They then compared the way the cells developed in the organoids and found that the motor nerve cells from healthy people were fully formed by day 35. However, the cells from people with SMA started to degenerate before they got to that point.

They also found that the protein problem that causes SMA to develop did so by causing the motor nerve cells to divide, something they don’t normally do. So, by blocking the mechanism that caused the cells to divide they were able to prevent the cells from dying.

In an article in Science and Technology Research News lead researcher Shi-Yan Ng said this approach could help unlock clues to other diseases such as ALS.

“We are one of the first labs to report the formation of spinal organoids. Our study presents a new method for culturing human spinal-cord-like tissues that could be crucial for future research.”

Just yesterday the CIRM Board awarded almost $4 million to Ankasa Regenerative Therapeutics to try and develop a treatment for another debilitating back problem called degenerative spondylolisthesis.

And finally, organoid modeling was used to better understand and study an infectious disease. Scientists from the Max Planck Institute for Infection Biology in Berlin created fallopian tube organoids from normal human cells. Fallopian tubes are the pair of tubes found inside women along which the eggs travel from the ovaries to the uterus. The scientists observed the effects of chronic infections of Chlamydia, a sexually transmittable infection. It was discovered that chronic infections lead to permanent changes at the DNA level as the cells age. These changes to DNA are permanent even after the infection is cleared, and could be indicative of the increased risk of cervical cancer observed in women with Chlamydia or those that have contracted it in the past.

Stem Cell Agency Awards Almost $4 Million to Develop a Treatment for Spinal Degeneration

Today the governing Board of the California Institute for Regenerative Medicine (CIRM) awarded $3.9 million to Ankasa Regenerative Therapeutics for a promising approach to treat a degenerative condition that can cause chronic, progressive back pain.

As we get older, the bones, joints and ligaments in our back become weak and less able to hold the spinal column in alignment.  As a result, an individual vertebral bone in our spine may slip forward over the one below it, compressing the nerves in the spine, and causing lower back pain or radiating pain.  This condition, called degenerative spondylolisthesis, primarily affects individuals over the age of 50 and, if left untreated, can cause intense pain and further degeneration of adjacent regions of the spine.

Current treatment usually involves taking bone from one of the patient’s other bones, and moving it to the site of the injury.  The transplanted bone contains stem cells necessary to generate new bone.  However, there is a caveat to this approach— as we get older the grafts become less effective because the stem cells in our bones are less efficient at making new bone.  The end result is little or no bone healing. 

Ankasa has developed ART352-L, a protein-based drug product meant to enhance the bone healing properties of these bone grafts.  ART352-L works by stimulating bone stem cells to  increase the amount of bone produced by the graft.

The award is in the form of a CLIN1 grant, with the goal of completing the testing needed to apply to the Food and Drug Administration (FDA) for permission to start a clinical trial in people.

This is a project that CIRM has supported through earlier phases of research.

“We are excited to see the development that this approach has made since its early stages and reflects our commitment to supporting the most promising science and helping it advance to the clinic,” says Maria T. Millan, MD, President & CEO of CIRM. “There is an unmet medical need in older patients with bone disorders such as degenerative spondylolisthesis.  As our population ages, it is important for us to invest in potential treatments such as these that can help alleviate a debilitating condition that predisposes to additional and fatal medical complications.”

See the animated video below for a descriptive and visual synopsis of degenerative spondylolisthesis.

Newly developed biosensor can target leukemic stem cells

Dr. Michael Milyavsky (left) and his research student Muhammad Yassin (right). Image courtesy of Tel Aviv University.

Every three minutes, one person in the United States is diagnosed with a blood cancer, which amounts to over 175,000 people every year. Every nine minutes, one person in the United States dies from a blood cancer, which is over 58,000 people every year. These eye opening statistics from the Leukemia & Lymphoma Society demonstrate why almost one in ten cancer deaths in 2018 were blood cancer related.

For those unfamiliar with the term, a blood cancer is any type of cancer that begins in blood forming tissue, such as those found in the bone marrow. One example of a blood cancer is leukemia, which results in the production of abnormal blood cells. Chemotherapy and radiation are used to wipe out these cells, but the blood cancer can sometimes return, something known as a relapse.

What enables the return of a blood cancer such as leukemia ? The answer lies in the properties of cancer stem cells, which have the ability to multiply and proliferate and can resist the effects of certain types of chemotherapy and radiation. Researchers at Tel Aviv University are looking to decrease the rate of relapse in blood cancer by targeting a specific type of cancer stem cell known as a leukemic stem cell, which are often found to be the most malignant.

Dr. Michael Milyavsky and his team at Tel Aviv University have developed a biosensor that is able to isolate, label, and target specific genes found in luekemic stem cells. Their findings were published on January 31, 2019 in Leukemia.

In a press release Dr. Milyavsky said:

“The major reason for the dismal survival rate in blood cancers is the inherent resistance of leukemic stem cells to therapy, but only a minor fraction of leukemic cells have high regenerative potential, and it is this regeneration that results in disease relapse. A lack of tools to specifically isolate leukemic stem cells has precluded the comprehensive study and specific targeting of these stem cells until now.”

In addition to isolating and labeling leukemic stem cells, Dr. Milyavsky and his team were able to demonstrate that the leukemic stem cells labeled by their biosensor were sensitive to an inexpensive cancer drug, highlighting the potential this technology has in creating more patient-specific treatment options.

In the article, Dr. Milyavsky said:

” Using this sensor, we can perform personalized medicine oriented to drug screens by barcoding a patient’s own leukemia cells to find the best combination of drugs that will be able to target both leukemia in bulk as well as leukemia stem cells inside it.”

The researchers are now investigating genes that are active in leukemic stem cells in the hope finding other druggable targets.

CIRM has funded two clinical trials that also use a more targeted approach for cancer treatment. One of these trials uses an antibody to treat chronic lymphocytic leukemia (CLL) and the other trial uses a different antibody to treat acute myeloid leukemia (AML).

Stem cell byproducts provide insight into cure for spina bifida

A diagram of an infant born with spina bifida, a birth defect where there is an incomplete closing of the backbone portion of the spinal cord. Photo courtesy of the Texas Children’s Hospital website.

Some of you might remember a movie in the early 2000s by the name of “Miracle in Lane 2”. The film is based on an inspirational true story and revolves around a boy named Justin Yoder entering a soapbox derby competition. In the movie, Justin achieves success as a soapbox derby driver while adapting to the challenges of being in a wheelchair.

Scene from “Miracle in Lane 2”

The reason that Justin is unable to walk is due to a birth defect known as spina bifida, which causes an incomplete closing of the backbone portion of the spinal cord, exposing tissue and nerves. In addition to difficulties with walking, other problems associated with this condition are problems with bladder or bowel control and accumulation of fluid in the brain.

According to the Center for Disease Control (CDC) , each year about 1,645 babies in the US are born with spina bifida, with Hispanic women having the highest rate of children born with the condition. There is currently no cure for this condition, but researchers at UC Davis are one step closer to changing that.

Dr. Aijun Wang examining cells under a microscope. He has identified stem cell byproducts that protect neurons. Photo courtesy of UC Regents/UC Davis Health

Dr. Aijun Wang, Dr. Diana Farmer, and their research team have identified crucial byproducts produced by stem cells that play an important role in protecting neurons. These byproducts could assist with improving lower-limb motion in patients with spina bifida.

Prior to this discovery, Dr. Farmer and Dr. Wang demonstrated that prenatal surgery combined with connective tissue (e.g. stromal cells) derived from stem cells improved hind limb control in dogs with spina bifida. Below you can see a clip of two English bulldogs with spina bifida who are now able to walk.

Their findings were published in the Journal of the Federation of American Societies for Experimental Biology on February 12, 2019.

The team will use their findings to perfect the neuroprotective qualities of a stem cell treatment developed to improve locomotive problems associated with spina bifida.

In a public release posted by EurekaAlert!, Dr. Wang is quoted as saying, “We are excited about what we see so far and are anxious to further explore the clinical applications of this research.”

The discovery and development of a treatment for spina bifida was funded by a $5.66 million grant from CIRM. You can read more about that award and spina bifida on a previous blog post linked here.

Gene therapy gives patient a cure and a new lease on life

Brenden Whittaker (left), of Ohio, is a patient born with a rare genetic immune disease who was treated at the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center in a CIRM funded gene therapy trial. Dr. David Williams (on right) is Brenden’s treating physician.
Photo courtesy of Rose Lincoln – Harvard Staff Photographer

Pursuing an education can be quite the challenge in itself without the added pressure of external factors. For Brenden Whittaker, a 25 year old from Ohio, the constant trips to the hospital and debilitating nature of an inherited genetic disease made this goal particularly challenging and, for most of his life, out of sight.

Brenden was born with chronic granulomatous disease (CGD), a rare genetic disorder that affects the proper function of neutrophils, a type of white blood cell that is an essential part of the body’s immune system. This leads to recurring bacterial and fungal infections and the formation of granulomas, which are clumps of infected tissue that arise as the body attempts to isolate infections it cannot combat. People with CGD are often hospitalized routinely and the granulomas themselves can obstruct digestive pathways and other pathways in the body. Antibiotics are used in an attempt to prevent infections from occurring, but eventually patients stop responding to them. One in two people with CGD do not live past the age of 40.

In Brenden’s case, when the antibiotics he relied on started failing, the doctors had to resort to surgery to cut out an infected lobe of his liver and half his right lung. Although the surgery was successful, it would only be a matter of time before a vital organ was infected and surgery would no longer be an option.

This ultimately lead to Brenden becoming the first patient in a CGD gene therapy trial at the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center.  The trial, lead by UCLA’s Dr. Don Kohn thanks to a CIRM grant, combats the disease by correcting the dysfunctional gene inside a patient’s blood stem cells. The patient’s corrected blood stem cells are then reintroduced, allowing the body to produce properly functioning neutrophils, rebooting the immune system.

It’s been a little over three years since Brenden received this treatment in late 2015, and the results have been remarkable. Dr. David Williams, Brenden’s treating physician, expected Brenden’s body to produce at least 10 percent of the functional neutrophils, enough so that Brenden’s immune system would provide protection similar to somebody without CGD. The results were over 50 percent, greatly exceeding expectations.

Brenden Whittaker mowing the lawn in the backyard of his home in Columbus, Ohio. He is able to do many more things without the fear of infection since participating in the trial. Photo courtesy of Colin McGuire

In an article published by The Harvard Gazette, Becky Whittaker, Brendan’s mother, is quoted as saying, ““Each day that he’s free of infection, he’s able to go to class, he’s able to work at his part-time job, he’s able to mess around playing with the dog or hanging out with friends…[this] is a day I truly don’t believe he would have had beyond 2015 had something not been done.”

In addition to the changes to his immune system, the gene therapy has reinvigorated Brenden’s drive for the future. Living with CGD had caused Brenden to miss out on much of his schooling throughout the years, having to take constant pauses from his academics at a community college. Now, Brenden aims to graduate with an associate’s degree in health sciences in the spring and transfer to Ohio State in the fall for a bachelor’s degree program. In addition to this, Brenden now has dreams of attending medical school.

In The Harvard Gazette article, Brenden elaborates on why he wants to go to medical school saying, ” Just being the patient for so long, I want to give back. There are so many people who’ve been there for me — doctors, nurses who’ve been there for me [and] helped me for so long.”

In a press release dated February 25, 2019, Orchard Therapeutics, a biopharmaceutical company that is continuing the aforementioned approach for CGD, announced that six patients treated have shown adequate neutrophil function 12 months post treatment. Furthermore, these six patients no longer receive antibiotics related to CGD. Orchard Therapeutics also announced that they are in the process of designing a registrational trial for CGD.

Antibody effective in cure for rare blood disorders

3D illustration of an antibody binding to a designated target.
Illustration created by Audra Geras.

A variety of diseases can be traced to a simple root cause: problems in the bone marrow. The bone marrow contains specialized stem cells known as hematopoietic stem cells (HSCs) that give rise to different types of blood cells. As mentioned in a previous blog about Sickle Cell Disease (SCD), one problem that can occur is the production of “sickle like” red blood cells. In blood cancers like leukemia, there is an uncontrollable production of abnormal white blood cells. Another condition, known as myelodysplastic syndromes (MDS), are a group of cancers in which immature blood cells in the bone marrow do not mature and therefore do not become healthy blood cells.

For diseases that originate in the bone marrow, one treatment involves introducing healthy HSCs from a donor or gene therapy. However, before this type of treatment can take place, all of the problematic HSCs must be eliminated from the patient’s body. This process, known as pre-treatment, involves a combination of chemotherapy and radiation, which can be extremely toxic and life threatening. There are some patients whose condition has progressed to the point where their bodies are not strong enough to withstand pre-treatment. Additionally, there are long-term side effects that chemotherapy and radiation can have on infant children that are discussed in a previous blog about pediatric brain cancer.

Could there be a targeted, non-toxic approach to eliminating unwanted HSCs that can be used in combination with stem cell therapies? Researchers at Stanford say yes and have very promising results to back up their claim.

Dr. Judith Shizuru and her team at Stanford University have developed an antibody that can eliminate problematic blood forming stem cells safely and efficiently. The antibody is able to identify a protein on HSCs and bind to it. Once it is bound, the protein is unable to function, effectively removing the problematic blood forming stem cells.

Dr. Shizuru is the senior author of a study published online on February 11th, 2019 in Blood that was conducted in mice and focused on MDS. The results were very promising, demonstrating that the antibody successfully depleted human MDS cells and aided transplantation of normal human HSCs in the MDS mouse model.

This proof of concept holds promise for MDS as well as other disease conditions. In a public release from Stanford Medicine, Dr. Shizuru is quoted as saying, “A treatment that specifically targets only blood-forming stem cells would allow us to potentially cure people with diseases as varied as sickle cell disease, thalassemia, autoimmune disorders and other blood disorders…We are very hopeful that this body of research is going to have a positive impact on patients by allowing better depletion of diseased cells and engraftment of healthy cells.”

The research mentioned was partially funded by us at CIRM. Additionally, we recently awarded a $3.7 million dollar grant to use the same antibody in a human clinical trial for the so-called “bubble baby disease”, which is also known as severe combined immunodeficiency (SCID). You can read more about that award on a previous blog post linked here.