Stem Cell Agency Approves Funding for Clinical Trials Targeting Parkinson’s Disease and Blindness

The governing Board of the California Institute for Regenerative Medicine (CIRM) yesterday invested $32.92 million to fund the Stem Cell Agency’s first clinical trial in Parkinson’s disease (PD), and to support three clinical trials targeting different forms of vision loss.

This brings the total number of clinical trials funded by CIRM to 60.

The PD trial will be carried out by Dr. Krystof Bankiewicz at Brain Neurotherapy Bio, Inc. He is using a gene therapy approach to promote the production of a protein called GDNF, which is best known for its ability to protect dopaminergic neurons, the kind of cell damaged by Parkinson’s. The approach seeks to increase dopamine production in the brain, alleviating PD symptoms and potentially slowing down the disease progress.

David Higgins, PhD, a CIRM Board member and patient advocate for Parkinson’s says there is a real need for new approaches to treating the disease. In the US alone, approximately 60,000 people are diagnosed with PD each year and it is expected that almost one million people will be living with the disease by 2020.

“Parkinson’s Disease is a serious unmet medical need and, for reasons we don’t fully understand, its prevalence is increasing. There’s always more outstanding research to fund than there is money to fund it. The GDNF approach represents one ‘class’ of potential therapies for Parkinson’s Disease and has the potential to address issues that are even broader than this specific therapy alone.”

The Board also approved funding for two clinical trials targeting retinitis pigmentosa (RP), a blinding eye disease that affects approximately 150,000 individuals in the US and 1.5 million people around the world. It is caused by the destruction of light-sensing cells in the back of the eye known as photoreceptors.  This leads to gradual vision loss and eventually blindness.  There are currently no effective treatments for RP.

Dr. Henry Klassen and his team at jCyte are injecting human retinal progenitor cells (hRPCs), into the vitreous cavity, a gel-filled space located in between the front and back part of the eye. The proposed mechanism of action is that hRPCs secrete neurotrophic factors that preserve, protect and even reactivate the photoreceptors, reversing the course of the disease.

CIRM has supported early development of Dr. Klassen’s approach as well as preclinical studies and two previous clinical trials.  The US Food and Drug Administration (FDA) has granted jCyte Regenerative Medicine Advanced Therapy (RMAT) designation based on the early clinical data for this severe unmet medical need, thus making the program eligible for expedited review and approval.

The other project targeting RP is led by Dr. Clive Svendsen from the Cedars-Sinai Regenerative Medicine Institute. In this approach, human neural progenitor cells (hNPCs) are transplanted to the back of the eye of RP patients. The goal is that the transplanted hNPCs will integrate and create a protective layer of cells that prevent destruction of the adjacent photoreceptors. 

The third trial focused on vision destroying diseases is led by Dr. Sophie Deng at the University of California Los Angeles (UCLA). Dr. Deng’s clinical trial addresses blinding corneal disease by targeting limbal stem cell deficiency (LSCD). Under healthy conditions, limbal stem cells (LSCs) continuously regenerate the cornea, the clear front surface of the eye that refracts light entering the eye and is responsible for the majority of the optical power. Without adequate limbal cells , inflammation, scarring, eye pain, loss of corneal clarity and gradual vision loss can occur. Dr. Deng’s team will expand the patient’s own remaining LSCs for transplantation and will use  novel diagnostic methods to assess the severity of LSCD and patient responses to treatment. This clinical trial builds upon previous CIRM-funded work, which includes early translational and late stage preclinical projects.

“CIRM funds and accelerates promising early stage research, through development and to clinical trials,” says Maria T. Millan, MD, President and CEO of CIRM. “Programs, such as those funded today, that were novel stem cell or gene therapy approaches addressing a small number of patients, often have difficulty attracting early investment and funding. CIRM’s role is to de-risk these novel regenerative medicine approaches that are based on rigorous science and have the potential to address unmet medical needs. By de-risking programs, CIRM has enabled our portfolio programs to gain significant downstream industry funding and partnership.”

CIRM Board also awarded $5.53 million to Dr. Rosa Bacchetta at Stanford to complete work necessary to conduct a clinical trial for IPEX syndrome, a rare disease caused by mutations in the FOXP3 gene. Immune cells called regulatory T Cells normally function to protect tissues from damage but in patients with IPEX syndrome, lack of functional Tregs render the body’s own tissues and organs to autoimmune attack that could be fatal in early childhood.  Current treatment options include a bone marrow transplant which is limited by available donors and graft versus host disease and immune suppressive drugs that are only partially effective. Dr. Rosa Bacchetta and her team at Stanford will use gene therapy to insert a normal version of the FOXP3 gene into the patient’s own T Cells to restore the normal function of regulatory T Cells.

The CIRM Board also approved investing $15.80 million in four awards in the Translational Research program. The goal of this program is to help promising projects complete the testing needed to begin talking to the US Food and Drug Administration (FDA) about holding a clinical trial.

The TRAN1 Awards are summarized in the table below:

ApplicationTitleInstitutionAward Amount
TRAN1 11536Ex Vivo Gene Editing of Human Hematopoietic Stem Cells for the Treatment of X-Linked Hyper IgM Syndrome  UCLA $4,896,628
TRAN1 11555BCMA/CS1 Bispecific CAR-T Cell Therapy to Prevent Antigen Escape in Multiple Myeloma  UCLA $3,176,805
TRAN1 11544 Neural Stem cell-mediated oncolytic immunotherapy for ovarian cancer  City of Hope $2,873,262
TRAN1 11611Development of a human stem cell-derived inhibitory neuron therapeutic for the treatment of chronic focal epilepsyNeurona Therapeutics$4,848,750

Newly discovered “don’t eat me” signal shows potential for ovarian and triple-negative breast cancer treatment

Stanford researchers have found that cancer cells have a protein called CD24 on their surface that enables them to protect themselves against the body’s immune cells.
Courtesy of Shutterstock

Getting a breast cancer diagnosis is devastating news in and of itself. Currently, there are treatment options that target three different types of receptors, which are named hormone epidermal growth factor receptor 2 (HER-2), estrogen receptors (ER), and progesterone receptors (PR), commonly found in breast cancer cells, . Unfortunately, in triple-negative breast cancer, which occurs in 10-20% of breast cancer cases, all three receptors are absent, making this form of breast cancer very aggressive and difficult to treat.

In recent years, researchers have discovered that proteins on the cell surface can tell macrophages, an immune cell designed to detect and engulf foreign or abnormal cells, not to eat and destroy them. This can be useful to help normal cells keep the immune system from attacking them, but cancer cells can also use these “don’t eat me” signals to hide from the immune system. 

An illustration of a macrophage, a vital part of the immune system, engulfing and destroying a cancer cell. Antibody 5F9 blocks a “don’t eat me” signal emitted from cancer cells. Courtesy of Forty Seven, Inc.

In fact, because of this concept, a CIRM-funded clinical trial is being conducted that uses an antibody called 5F9 to block a “don’t eat me” signal known as CD47 that is found in cancer cells. The results of this trial, which have been announced in a previous blog post, are very promising.

Further building on this concept, a CIRM-funded study has now discovered a potential new target for triple-negative breast cancer as well as ovarian cancer. Dr. Irv Weissman and a team of researchers at Stanford University have discovered an additional “don’t eat me” signal called CD24 that cancers seem to use to evade detection and destruction by the immune system.

In a press release, Dr. Weissman talks about his work with CD47 and states that,

“Finding that not all patients responded to anti-CD47 antibodies helped fuel our research at Stanford to test whether non-responder cells and patients might have alternative ‘don’t eat me’ signals.” 

The scientists began by looking for signals that were produced more highly in cancers than in the tissues from which the cancers arose. It is here that they discovered CD24 and then proceeded to implant human breast cancer cells in mice for testing. When the CD24 signaling was blocked, the mice’s immune system attacked the cancer cells.

An important discovery was that ovarian and triple-negative breast cancer were highly affected by blocking of CD24 signaling. The other interesting discovery was that the effectiveness of CD24 blockage seems to be complementary to CD47 blockage. In other words, some cancers, like blood cancers, seem to be highly susceptible to blocking CD47, but not to CD24 blockage. For other cancers, like ovarian cancer, the opposite is true. This could suggest that most cancers will be susceptible to the immune system by blocking the CD24 or CD47 signal, and that cancers may be even more vulnerable when more than one “don’t eat me” signal is blocked.

Dr. Weissman and his team are now hopeful that potential therapies to block CD24 signaling will follow in the footsteps of the clinical trials related to CD47.

The full results to the study were published in Nature.

Stem cell stories that caught our eye: better ovarian cancer drugs, creating inner ear tissue, small fish big splash

Two drugs are better than one for ovarian cancer (Karen Ring). Earlier this week, scientists from UCLA reported that a combination drug therapy could be an effective treatment for 50% of aggressive ovarian cancers. The study was published in the journal Precision Oncology and was led by Dr. Sanaz Memarzadeh.

Women with high-grade ovarian tumors have an 85% chance of tumor recurrence after treatment with a common chemotherapy drug called carboplatin. The UCLA team found in a previous study that ovarian cancer stem cells are to blame because they are resistant to carboplatin. It’s because these stem cells have an abundance of proteins called cIAPs, which prevent cell death from chemotherapy.

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Ovarian cancer cells (blue) expressing cIAP protein (red) on the left are more sensitive to a combination therapy than cancer cells that don’t express the protein on the right. (UCLA Broad Stem Cell Research Center/Precision Oncology)

Memarzadeh discovered that an experimental drug called birinapant made some ovarian cancer tumors more sensitive to chemotherapy treatment by breaking down cIAPs. This gave her the idea that combining the two drugs, birinapant and carboplatin, might be a more effective strategy for treating aggressive ovarian tumors.

By treating with the two drugs simultaneously, the scientists improved the survival rate of mice with ovarian cancer. They also tested this combo drug treatment on 23 ovarian cancer cell lines derived from women with highly aggressive tumors. The treatment killed off half of the cell lines indicating that some forms of this cancer are resistant to the combination treatment.

When they measured the levels of cIAPs in the human ovarian cancer cell lines, they found that high levels of the proteins were associated with ovarian tumor cells that responded well to the combination treatment. This is exciting because it means that clinicians can analyze tumor biopsies for cIAP levels to determine whether certain ovarian tumors would respond well to combination therapy.

Memarzadeh shared her plans for future research in a UCLA news release,

“I believe that our research potentially points to a new treatment option. In the near future, I hope to initiate a phase 1/2 clinical trial for women with ovarian cancer tumors predicted to benefit from this combination therapy.”

In a first, researchers create inner ear tissue. From heart muscle to brain cells to insulin-producing cells, researchers have figured out how to make a long list of different human cell types using induced pluripotent stem cells (iPSCs) – cells taken from the body and reprogrammed into a stem cell-like state.

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Human inner ear organoid with sensory hair cells (cyan) and sensory neurons (yellow). An antibody for the protein CTBP2 reveals cell nuclei as well as synapses between hair cells and neurons (magenta). | Photo: Karl Koehler

This week, a research group at the Indiana University School of Medicine successfully added inner ear cells to that list. This feat, published in Nature Biotechnology, is especially important given the fact that the inner ear is one of the few parts of the body that cannot be biopsied for further examination. With these cells in hands, new insights into the causes of hearing loss and balance disorders may be on the horizon.

The inner ear contains 75,000 sensory hair cells that convert sound waves into electrical signals to the brain. Loud noises, drug toxicity, and genetic mutations can permanently damage the hair cells leading to hearing loss and dizziness. Over 15%  of the U.S. population have some form of hearing loss and that number swells to 67% for people over 75.

Due to the complex shape of the inner ear, the team grew the iPSCs into three dimensional balls of cells rather than growing them as a flat layer of cells on a petri dish. With educated guesses sprinkled in with some trial and error, the scientists, for the time, identified a recipe of proteins that stimulated the iPSCs to transform into inner ear tissue. And like any great recipe, it wasn’t so much the ingredient list but the timing that was key:

“If you apply these signals at the wrong time you can potentially generate a brain instead of an inner ear,” first author Dr. Karl Koehler said in an interview with Gizmodo. “The real breakthrough is that we figured out the exact timing to do each one of these [protein] treatments.”

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Senior author, Eri Hashino, Ph.D., and first author, Karl R. Koehler, Ph.D. Photo: Indiana University

Careful examination shows that the tissue, referred to as organoids, not only contained the sensory hair cells of the inner ear cell but also nerve cells, or neurons, that are responsible for relaying the sound waves to the brain. Koehler explained the importance of this result in a press release:

“We also found neurons, like those that transmit signals from the ear to the brain, forming connections with sensory cells. This is an exciting feature of these organoids because both cell types are critical for proper hearing and balance.”

Though it’s still early days, these iPSC-derived inner ear organoids are a key step toward the ultimate goal of repairing hearing loss. Senior author, Dr. Eri Hashino, talked about the team’s approach to reach that goal:

“Up until now, potential drugs or therapies have been tested on animal cells, which often behave differently from human cells. We hope to discover new drugs capable of helping regenerate the sound-sending hair cells in the inner ear of those who have severe hearing problems.”

This man’s research is no fish tale
And finally, we leave you this week with a cool article and video by STAT. It features Dr. Leonard Zon of Harvard University and his many, many tanks full of zebrafish. This little fish has made a huge splash in understanding human development and disease. But don’t take my word for it, watch the video!