Sickle Cell Clinical Trial Aims to Cure Disease by Correcting Patient’s Mutated Gene

UCSF Benioff Children’s Hospital Oakland has received the largest research trial grant in its history to launch an innovative clinical trial that aims to cure sickle cell disease. The study, which plans to enroll its first patient later this year, will use CRISPR-Cas9 gene-editing technology on patients’ own blood stem cells to correct the mutated gene that causes the debilitating disorder.

Benioff Oakland researchers have received $17 million to support the four-year trial, in two grants of $8.4 million from the California Institute for Regenerative Medicine (CIRM) and $8.6 million from the NIH Cure Sickle Cell Initiative, supported by the National Heart, Lung, and Blood Institute (NHLBI).

portrait of Mark Walters
Mark Walters, MD, a professor of pediatrics at UCSF and principal investigator of the clinical trial and gene editing project. Photo by Barbara Ries

This trial is the first to apply CRISPR-Cas9 technology in humans and is part of a UC research consortium led by UCSF with UCLA and UC Berkeley. Researchers are recruiting patients for treatment in Oakland and Los Angeles, beginning with up to six adults with sickle cell disease. If found to be safe and effective, it will expand to enroll three adolescents aged 12 to 17 years old. Seven patients are expected to be treated in Oakland and two at UCLA.

It is the first time clinical researchers have attempted to correct a harmful beta-globin gene mutation in a patient’s own cells with non-virally delivered CRISPR gene-correction tools, according to Mark Walters, MD, a professor of pediatrics at UCSF and principal investigator of the clinical trial and gene editing project.

“This therapy has the potential to transform sickle cell disease care by producing an accessible, curative treatment that is safer than the current therapy of stem cell transplant from a healthy bone marrow donor,” Walters said. “If this is successfully applied in young patients, it has the potential to prevent irreversible complications of the disease.”

Sickle cell disease is a genetic blood disorder that affects the structure and function of hemoglobin, reduces the ability of red blood cells to transport oxygen efficiently, and progresses to a chronic vascular disease that affects approximately 100,000 Americans and millions worldwide, with a disproportionate effect on the Black community.

This therapy has the potential to transform sickle cell disease care by producing an accessible, curative treatment that is safer than the current therapy of stem cell transplant from a healthy bone marrow donor.

This clinical study continues BCH Oakland’s commitment to treating and finding a cure for sickle cell disease. The Comprehensive Sickle Cell Disease Center was created at the hospital in 1973 to provide expert diagnosis, treatment and long-term health management for children and adults with sickle cell disease. Now known as the BCH Oakland Sickle Cell Center of Excellence, it is recognized as having one of the largest and most comprehensive sickle cell programs in the Western United States.

This trial will combine CRISPR technology developed at Innovative Genomics Institute (IGI) – a joint UC Berkeley-UCSF initiative founded by Nobel Laureate Jennifer Doudna, PhD – with UCLA’s expertise in genetic analysis and cell manufacturing, as well as its clinical excellence in the field, and nearly 50 years of expertise at Benioff Children’s Oakland in sickle cell care, including cord blood and marrow transplantation, and gene therapy.

“The use of CRISPR gene editing to fix the mutation causing sickle cell disease in each patient’s own blood-forming stem cells required the development of new methods to produce more than 100 million cells per patient that are gene-corrected, healthy and pure,” said Donald Kohn, MD, medical director of the UCLA Human Gene and Cell Therapy Facility. “Previous research studies were limited to producing ½ to 2 million genetically corrected cells, so this represents a significant increase in scale.”

The disease is caused by a single-letter change, or mutation, in human DNA. This trial will use CRISPR genome editing to correct this mutation directly. The project team from UCSF, the IGI, and UCLA have developed CRISPR_SCD001, a patient-specific blood stem cell therapy that has been modified by a CRISPR-Cas9 nuclease to stimulate repair of the sickle mutation. In the current trial, the patient’s blood stem cells will be extracted and sent to UCLA’s gene manufacturing lab to be processed using electrical pulses that create temporary pores in their membranes. These pores allow the CRISPR-Cas9 platform to enter the cells and travel to the nucleus, where it corrects the sickle cell mutation before the cells are reintroduced to the patient.

“The goal is to develop a cure that is not just safe and effective, but one that is affordable by to those who need it most,” Doudna said. “There have been a lot of promising developments in recent years with CRISPR-based therapies for sickle cell and other genetic diseases, but it’s essential that we have studies like this that can help us create truly accessible cures.”

As part of its legacy, BCH Oakland was recognized for establishing the first not-for-profit sibling donor cord blood bank, leading to children being cured of sickle cell disease and other blood diseases. Among its many accomplishments in treating sickle cell disease, BCH Oakland scientists studied and received FDA approval for the drug Voxelotor to improve hemoglobin levels and reduce anemia and hemolysis in sickle cell patients.

Going forward, the UCSF research team is hoping to use expanded resources under development in the UCSF Living Therapeutics Initiative as this new treatment is expanded, including the potential to manufacture the investigational cell therapy product at UCSF.

The University of California, San Francisco (UCSF) is exclusively focused on the health sciences and is dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. UCSF Health, which serves as UCSF’s primary academic medical center, includes top-ranked specialty hospitals and other clinical programs, and has affiliations throughout the Bay Area.

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