For years scientists have been touting the potential of CRISPR, a gene editing tool that allows you to target a specific mutation and either cut it out or replace it with the corrected form of the gene. But like all new tools it had its limitations. One important one was the difficult in delivering the corrected gene to mature cells in large numbers.
Scientists at the Gladstone Institutes and U.C. San Francisco say they think they have found a way around that. And the implications for using this technique to develop new therapies for deadly diseases are profound.
In the past scientists used inactivated viruses as a way to deliver corrected copies of the gene to patients. We have blogged about UCLA’s Dr. Don Kohn using this approach to treat children born with SCID, a deadly immune disorder. But that was both time consuming and expensive.
CRISPR, on the other hand, showed that it could be easier to use and less expensive. But getting it to produce enough cells for an effective therapy proved challenging.
The team at Gladstone and UCSF found a way around that by switching from using CRISPR to deliver a double-stranded DNA to correct the gene (which is toxic to cells in large quantities), and instead using CRISPR to deliver a single stranded DNA (you can read the full, very technical description of their approach in the study they published in the journal Nature Biotechnology).
Alex Marson, MD, PhD, director of the Gladstone-UCSF Institute of Genomic Immunology and the senior author of the study, said this more than doubled the efficiency of the process. “One of our goals for many years has been to put lengthy DNA instructions into a targeted site in the genome in a way that doesn’t depend on viral vectors. This is a huge step toward the next generation of safe and effective cell therapies.”
It has another advantage too, according to Gladstone’s Dr. Jonathan Esensten, an author of the study. “This technology has the potential to make new cell and gene therapies faster, better, and less expensive.”
The team has already used this method to generate more than one billion CAR-T cells – specialized immune system cells that can target cancers such as multiple myeloma – and says it could also prove effective in targeting some rare genetic immune diseases.
The American Cancer Society estimates that this year in the United States, there will be 268,490 new cases of prostate cancer. It also estimates that 34,500 men will die from the cancer in 2022. Other than skin cancer, prostate cancer is the most common cancer in American men.
“We have a homegrown USC technology which shows a lot of promise. If the path that we are on ultimately proves successful, it could revolutionize the treatment of not only prostate cancer but also other cancers,” said principal investigator Dr. Preet M. Chaudhary, a professor of medicine at the Keck School of Medicine of USC.
A new approach to immunotherapy
CAR-T cell therapy—which is now approved by the U.S. Food and Drug Administration (FDA) to treat several blood cancers—has been revolutionary for certain patients. In CAR-T therapy, a patient’s T-cells—a key part of their immune system—are extracted and genetically engineered to express the chimeric antigen receptor (CAR). The modified T-cells are then reinjected into the patient, where CAR enables them to selectively seek out, bind to, and kill cancer cells.
But its success in treating blood cancers has not translated into effectiveness against solid tumor cancers, such as prostate, breast, brain, gastrointestinal, skin and lung cancer.
“The bottom line is that people have tried to replicate the success of CAR-T cell therapy with solid tumor cancers, and have been mostly unsuccessful,” Chaudhary said.
SIR-T therapy, in contrast, uses different receptors that more closely resemble the body’s natural T-cells. Chaudhary and his team tested thousands of prototypes over an eight-year period to develop receptors that are effective and safe for solid tumors, including prostate cancer. An initial round of tests in mice yielded very promising results, prompting Chaudhary to apply for funding from CIRM.
With CIRM funding, Chaudhary and his team can now begin conducting preclinical trials of SIR-T therapy. Their research over the next two and a half years will culminate in an application for FDA approval to begin clinical trials in humans.
Chaudhary’s lab is also testing SIR-T therapy for other types of cancer, including melanoma, kidney cancer, lymphoma and a different molecule involved in prostate cancer.
“This technology has a lot of different applications, so we are working to ensure the platform works across disease types,” Chaudhary said. “The series of grants we’ve received reflects a lot of excitement about the SIR-T platform.”
Every year millions of Americans suffer damage to their cartilage, either in their knee or other joints, that can eventually lead to osteoarthritis, pain and immobility. Today the governing Board of the California Institute for Regenerative Medicine (CIRM) approved two projects targeting repair of damaged cartilage.
The projects were among 17 approved by CIRM as part of the DISC2 Quest Discovery Program. The program promotes the discovery of promising new stem cell-based and gene therapy technologies that could be translated to enable broad use and ultimately, improve patient care.
Dr. Darryl D’Lima and his team at Scripps Health were awarded $1,620,645 to find a way to repair a torn meniscus. Every year around 750,000 Americans experience a tear in their meniscus, the cartilage cushion that prevents the bones in the knee grinding against each other. These injuries accelerate the early development of osteoarthritis, for which there is no effective treatment other than total joint replacement, which is a major operation. There are significant socioeconomic benefits to preventing disabling osteoarthritis. The reductions in healthcare costs are also likely to be significant.
The team will use stem cells to produce meniscal cells in the lab. Those are then seeded onto a scaffold made from collagen fibers to create tissue that resembles the knee meniscus. The goal is to show that, when placed in the knee joint, this can help regenerate and repair the damaged tissue.
This research is based on an earlier project that CIRM funded. It highlights our commitment to helping good science progress, hopefully from the bench to the bedside where it can help patients.
Dr. Kevin Stone and his team at The Stone Research Foundation for Sports Medicine and Arthritis were awarded $1,316,215 to develop an approach to treat and repair damaged cartilage using a patient’s own stem cells.
They are using a paste combining the patient’s own articular tissue as well as Mesenchymal Stem Cells (MSC) from their bone marrow. This mixture is combined with an adhesive hydrogel to form a graft that is designed to support cartilage growth and can also stick to surfaces without the need for glue. This paste will be used to augment the use of a microfracture technique, where micro-drilling of the bone underneath the cartilage tear brings MSCs and other cells to the fracture site. The hope is this two-pronged approach will produce an effective and functional stem cell-based cartilage repair procedure.
If effective this could produce a minimally invasive, low cost, one-step solution to help people with cartilage injuries and arthritis.
The full list of DISC2 grantees is:
Principal Investigator and Institution
Preclinical development of an exhaustion-resistant CAR-T stem cell for cancer immunotherapy
Ansuman Satpathy – Stanford University
Generating deeper and more durable BCMA CAR T cell responses in Multiple Myeloma through non-viral knockin/knockout multiplexed genome engineering
Julia Carnevale – UC San Francisco
Injectable, autologous iPSC-based therapy for spinal cord injury
Sarah Heilshorn – Stanford University
New noncoding RNA chemical entity for heart failure with preserved ejection fraction.
Eduardo Marban – Cedars-Sinai Medical Center
Modulation of oral epithelium stem cells by RSpo1 for the prevention and treatment of oral mucositis
Jeffrey Linhardt – Intact Therapeutics Inc.
Transplantation of genetically corrected iPSC-microglia for the treatment of Sanfilippo Syndrome (MPSIIIA)
There is no benefit in helping create a miraculous new therapy that can cure people and save lives if no one except the super-rich can afford it. That’s why the California Institute for Regenerative Medicine (CIRM) has made creating a roadmap to help make new treatments both available and affordable for all Californians a central pillar of its new 5-year Strategic Plan.
New treatments based on novel new technologies often seem to come with a gob-smacking price tag. When Kymriah, a CAR-T cell cancer therapy, was approved it cost $475,000 for one treatment course. When the FDA approved Zolgensma to treat spinal muscular atrophy, a genetic disorder that causes muscle wasting and weakness, the cost was $2.1 million for one dose.
Part of the pricing is due to high manufacturing cost and the specialized resources needed to deliver the treatments. The treatments themselves are showing that they can be one-and-done options for patients, meaning just one treatment may be all they need to be cured. But even with all that innovation and promise the high price may impact access to patients in need.
At CIRM we believe that if California taxpayer money has helped researchers develop a new therapy, Californians should be able to get that therapy. To try and ensure they can we have created the Accessibility and Affordability Working Group (AAWG). The groups mission is to find a way to overcome the hurdles that stand between a patient and the treatment they need.
The AAWG will work with politicians and policy makers, researchers and regulators, insurance companies and patient advocate organizations to gather the data and information needed to make these therapies available and affordable. Dr. Le Ondra Clark Harvey, a CIRM Board member and mental health advocate, says the barriers we have to confront are not just financial, they are racial and ethnic too.
We have already created a unique model for delivering stem cell therapies to patients through our Alpha Stem Cell Clinic Network. We are now setting out to build on that with our commitment to creating Community Care Centers of Excellence. But having world-class clinics capable of delivering life-saving therapies is not enough. We also need to make sure that Californians who need these treatments can get them regardless of who they are or their ability to pay.
Hematologic malignancies are cancers that affect the blood, bone marrow and lymph nodes and include different forms of leukemia and lymphoma. Current treatments can be effective, but in those patients that do not respond, there are few treatment options. Today, the governing Board of the California Institute for Regenerative Medicine (CIRM) approved investing $4.1 million in a therapy aimed at helping patients who have failed standard therapy.
Dr. Ezra Cohen, at the University of California San Diego, and Oncternal Therapeutics are targeting a protein called ROR1 that is found in B cell malignancies, such as leukemias and lymphomas, and solid tumors such as breast, lung and colon. They are using a molecule called a chimeric antigen receptor (CAR) that can enable a patient’s own T cells, an important part of the immune system, to target and kill their cancer cells. These cells are derived from a related approach with an antibody therapy that targets ROR1-binding medication called Cirmtuzumab, also created with CIRM support. This CAR-T product is designed to recognize and kill cancer stem cells that express ROR1.
This is a late-stage preclinical project so the goal is to show they can produce enough high-quality cells to treat patients, as well as complete other regulatory measures needed for them to apply to the US Food and Drug Administration (FDA) for permission to test the therapy in a clinical trial in people.
If given the go-ahead by the FDA the therapy will target patients with chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL) and acute lymphoblastic leukemia (ALL).
“CAR-T cell therapies represent a transformational advance in the treatment of hematologic malignancies,” says Dr. Maria T. Millan, CIRM’s President and CEO. “This approach addresses the need to develop new therapies for patients whose cancers are resistant to standard chemotherapies, who have few therapeutic options and a very poor chance or recovery.”
Earlier this week the CIRM ICOC Board awarded $14.5 million to fund three translational stage research projects (TRAN1), whose goal is to support early development activities necessary for advancement to a clinical study or broad end use of a potential therapy. Although all three projects have their distinct area of focus, they all utilize CAR-based cell therapy to treat a certain type of cancer. This approach involves obtaining T cells, which are an immune system cell that can destroy foreign or abnormal cells, and modifying them with a chimeric antigen receptor (CAR). This enables the newly created CAR-engineered cells to identify specific tumor signals and destroy the cancer. In the sections below we will take a deeper look at each one of these recently approved projects.
$2,663,144 was awarded to the University of California, San Francisco (UCSF) to develop specialized CAR-T cells that are able to recognize and destroy tumor cells in glioblastoma, an aggressive type of cancer that occurs in the brain and spinal cord. The specialized CAR-T cells have been created such that they are able to detect two specific signals expressed in glioblastoma. Hideho Okada, M.D., Ph.D. and his team at UCSF will test the therapy in mice with human glioblastoma grafts. They will be looking at preclinical safety and if the CAR-T cell therapy is able to produce a desired or intended result.
$5,949,651 was awarded to the University of California, Los Angeles (UCLA) to develop specialized CAR-engineered cells from human blood stem cells to treat multiple myeloma, a type of blood cancer. Lili Yang, Ph.D. and her team have developed a method using human blood stem cells to create invariant natural killer T (iNKT) cells, a special kind of T cell with unique features that can more effectively attack tumor cells using multiple mechanisms and migrate to and infiltrate tumor sites. After being modified with CAR, the newly created CAR-iNKT cells are able to target a specific signal present in multiple myeloma. The team will test the therapy in mice with human multiple myeloma. They will be looking at preclinical safety and if the CAR-iNKT cells are able to produce a desired or intended result.
Another $5,904,462 was awarded to UCLA to develop specialized CAR-T cells to treat melanoma, a form of skin cancer. Cristina Puig-Saus, Ph.D. and her team will use naïve/memory progenitor T cells (TNM), a subset of T cells enriched with stem cells and memory T cells, an immune cell that remains long after an infection has been eliminated. After modification with CAR, the newly created CAR-TNM cells will target a specific signal present in melanoma. The team will test the therapy in mice with human melanoma. They will be looking at preclinical safety and if the CAR-TNM cells are able to produce a desired or intended result.
Today the governing Board of the California Institute for Regenerative Medicine (CIRM) awarded $14.4 million for two new clinical trials for blood cancer and pediatric brain tumors.
These awards bring the total number of CIRM-funded clinical trials to 70.
$6.0 million was awarded to Immune-Onc Therapeutics to conduct a clinical trial for patients with acute myeloid leukemia (AML) and chronic myelomonocytic leukemia (CMML), both of which are types of blood cancer. AML affects approximately 20,000 people in the United States each year and has a 5-year survival rate of about 25 percent. Anywhere from 15-30 percent of CMML cases eventually progress into AML.
Paul Woodard, M.D. and his team will treat AML and CMML patients with an antibody therapy called IO-202 that targets leukemic stem cells. The antibody works by blocking a signal named LILRB4 whose expression is connected with decreased rates of survival in AML patients. The goal is to attain complete cancer remissions and prolonged survival.
$8.4 million was also awarded to City of Hope to conduct a clinical trial for children with malignant brain tumors. Brain tumors are the most common solid tumor of childhood, with roughly 5,000 new diagnoses per year in the United States.
Leo D. Wang, M.D., Ph.D. and his team will treat pediatric patients with aggressive brain tumors using chimeric antigen receptor (CAR) T cell therapy. The CAR T therapy involves obtaining a patient’s own T cells, which are an immune system cell that can destroy foreign or abnormal cells, and modifying them so that they are able to identify and destroy the brain tumors. The aim of this approach is to improve patient outcome.
“Funding the most promising therapies for aggressive blood cancer and brain tumors has always aligned with CIRM’s mission,” says Maria T. Millan, M.D., President and CEO of CIRM. “We are excited to fund these trials as the first of many near-term and future stem cell- and regenerative medicine-based approaches that CIRM will be able to support with bond funds under Proposition 14”.
In June of last year we wrote about how Dr. Scott Kitchen and his team at UCLA are engineering blood forming stem cells in order to fight HIV, a potentially deadly virus that attacks the immune system and can worsen into AIDS if left untreated. HIV causes havoc in the body by attacking T cells, a vital part of the body’s immune system that helps fight off infections and diseases.
Dr. Kitchen’s approach uses what is called Chimeric Antigen Receptor (CAR) T gene therapy. This is a type of immune therapy that involves genetically modifying the body’s own blood forming stem cells to create T cells that have the ability to fight HIV. These newly formed immune cells have the potential to not only destroy HIV-infected cells but to create “memory cells” that could provide lifelong protection from HIV infection.
Unfortunately, although the previously designed CAR T gene therapy was still able to create HIV fighting immune cells, the way the CAR T gene therapy was designed still had the potential to allow for HIV infection.
For this new study, the team modified the CAR T gene therapy such that the cells would be resistant to infection and allow for a more efficient and longer-lasting cell response against HIV than before.
While the previous approach allowed for the continuous production of new HIV-fighting T cells that persisted for more than two years, these cells are inactivated until they come across the HIV virus. The improved CAR T gene therapy engineers the body’s immune response to HIV rather than waiting for the virus to induce a response. This is similar in concept to how a vaccine prepares the immune system to respond against a virus. The new approach also creates a significant number of “memory” T cells that are capable of quickly responding to reactivated HIV.
The hope is that these findings can influence the development of T cells that are able carry “immune system” memory with the ability to recognize and kill virus-infected or cancerous cells.
At CIRM we are modest enough to know that we can’t do everything by ourselves. To succeed we need partners. And in UC Davis we have a terrific partner. The work they do in advancing stem cell research is exciting and really promising. But it’s not just the science that makes them so special. It’s also their compassion and commitment to caring for patients.
What follows is an excerpt from an article by Lisa Howard on the work they do at UC Davis. When you read it you’ll see why we are honored to be a part of this research.
Gene therapy research at UC Davis
UC Davis’ commitment to stem cell and gene therapy research dates back more than a decade.
In 2010, with major support from the California Institute for Regenerative Medicine (CIRM), UC Davis launched the UC Davis Institute for Regenerative Cures, which includes research facilities as well as a Good Manufacturing Practice (GMP) facility.
Led by Jan Nolta, a professor of cell biology and human anatomy and the director of the UC Davis Institute for Regenerative Cures, the new center leverages UC Davis’ network of expert researchers, facilities and equipment to establish a center of excellence aimed at developing lifelong cures for diseases.
Nolta began her career at the University of Southern California working with Donald B. Kohn on a cure for bubble baby disease, a condition in which babies are born without an immune system. The blood stem cell gene therapy has cured more than 50 babies to date.
Work at the UC Davis Gene Therapy Center targets disorders that potentially can be treated through gene replacement, editing or augmentation.
“The sectors that make up the core of our center stretch out across campus,” said Nolta. “We work with the MIND Institute a lot. We work with the bioengineering and genetics departments, and with the Cancer Center and the Center for Precision Medicine and Data Sciences.”
A recent UC Davis stem cell study shows a potential breakthrough for healing diabetic foot ulcers with a bioengineered scaffold made up of human mesenchymal stem cells (MSCs). Another recent study revealed that blocking an enzyme linked with inflammation enables stem cells to repair damaged heart tissue. A cell gene therapy study demonstrated restored enzyme activity in Tay-Sachs disease affected cells in humanized mouse models.
“Some promising and exciting research right now at the Gene Therapy Center comes from work with hematopoietic stem cells and with viral vector delivery,” said Nolta.
Hematopoietic stem cells give rise to other blood cells. A multi-institutional Phase I clinical trial using hematopoietic stem cells to treat HIV-lymphoma patients is currently underway at UC Davis.
“We are genetically engineering a patient’s own blood stem cells with genes that block HIV infection,” said Joseph Anderson, an associate professor in the UC Davis Department of Internal Medicine. The clinical trial is a collaboration with Mehrdad Abedi, the lead principal investigator.
“When the patients receive the modified stem cells, any new immune system cell, like T-cell or macrophage, that is derived from one of these stem cells, will contain the HIV-resistant genes and block further infection,” said Anderson.
He explained that an added benefit with the unique therapy is that it contains an additional gene that “tags” the stem cells. “We are able to purify the HIV-resistant cells prior to transplantation, thus enriching for a more protective cell population.
Kyle David Fink
Kyle David Fink, an assistant professor of neurology at UC Davis, is affiliated with the Stem Cell Program and Institute for Regenerative Cures. His lab is focused on leveraging institutional expertise to bring curative therapies to rare, genetically linked neurological disorders.
“We are developing novel therapeutics targeted to the underlying genetic condition for diseases such as CDKL5 deficiency disorder, Angelman, Jordan and Rett syndromes, and Juvenile Huntington’s disease,” said Fink.
The lab is developing therapies to target the underlying genetic condition using DNA-binding domains to modify gene expression in therapeutically relevant ways. They are also creating novel delivery platforms to allow these therapeutics to reach their intended target: the brain.
“The hope is that these highly innovative methods will speed up the progress of bringing therapies to these rare neurodegenerative disease communities,” said Fink.
Jasmine Carter, a graduate research assistant at the UC Davis Stem Cell Program, October 18, 2019. (AJ Cheline/UC Davis)
Developing potential lifetime cures
Among Nolta’s concerns is how expensive gene therapy treatments can be.
“Some of the therapies cost half a million dollars and that’s simply not available to everyone. If you are someone with no insurance or someone on Medicare, which reimburses about 65 percent, it’s harder for you to get these life-saving therapies,” said Nolta.
To help address that for cancer patients at UC Davis, Nolta has set up a team known as the “CAR T Team.”
Chimeric antigen receptor (CAR) T-cell therapy is a type of immunotherapy in which a patient’s own immune cells are reprogrammed to attack a specific protein found in cancer cells.
“We can develop our own homegrown CAR T-cells,” said Nolta. “We can use our own good manufacturing facility to genetically engineer treatments specifically for our UC Davis patients.”
Although safely developing stem cell treatments can be painfully slow for patients and their families hoping for cures, Nolta sees progress every day. She envisions a time when gene therapy treatments are no longer considered experimental and doctors will simply be able to prescribe them to their patients.
“And the beauty of the therapy is that it can work for the lifetime of a patient,” said Nolta.
Bryon Jenkin’s is one of the people we profiled in our recent 18 Month Report. The theme of the report is “Perseverance” and Byron certainly epitomizes that. This is his story.
A former Navy flight officer and accomplished athlete Byron Jenkins learned in June 2013 that he had multiple myeloma, an incurable blood cancer, and that it was eating through his bones. After five years of, chemotherapy, radiation, immunotherapy, and experimental procedures, he found himself bed ridden, exhausted, barely able to move. Byron says: “I was alive, but I wasn’t living.”
As the treatments lost their ability to hold the cancer at bay, Byron’s wife, family and close friends had made preparations for his seemingly inevitable demise.
Then Byron took part in a CIRM-funded CAR-T clinical trial for a treatment developed by Poseida Therapeutics. The team used Byron’s own immune system cells, re-engineered in the lab, to recognize the cancer and to fight back. Within two weeks Byron was feeling so much better he was able to stop taking all of his medications. “I haven’t taken so much as an aspirin since then.”
Two years later he is once again able to enjoy a full, active life with his family; biking, hiking and skiing with his wife and kids. He is back working full-time and only checks in with his oncologist once in a while.
Byron says despite his ordeal he never lost faith, that the love of his family helped give him the strength to continue to fight. “Hope kept me going through this long arduous process. This is the first treatment to give me a continued normal life. CAR-T was the answer to my prayers.”