10/13/2026
Here is the latest research CHOP Research Firsts: Leading the Way in Cell and Gene Therapy
September 14, 2026 in Where Discovery Leads · Last updated 3 weeks 6 days ago
Leading the Way in Cell and Gene Therapy
CHOP researchers have been at the forefront of cell and gene therapy, contributing to innovations in the field over decades of research.
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By Lauren Ingeno
Editor’s Note: In honor of America’s 250th birthday, we’re celebrating some of the “firsts” in science and medicine for Pediatrics that happened here at CHOP Research. This edition explores how CHOP researchers have been at the forefront of cell and gene therapy. View a short timeline video of CHOP Research Firsts, also featured at the end of this story.
Children’s Hospital of Philadelphia researchers have been at the forefront of the cell and gene therapy revolution, contributing to the first such treatments approved by the U.S. Food and Drug Administration. Their efforts have changed the landscape of the field and paved the way for medical breakthroughs, including treating the world’s first patient with a personalized gene-editing treatment.
“It is important that the broader public understands what gene therapies are, the capacity of these modalities for transformative treatments, the amount of work it takes to develop them, and to understand if they're effective and safe,” said Chief Scientific Strategy Officer Beverly Davidson, PhD, who holds the Katherine A. High Presidential Chair at CHOP Research Institute.
First to Cure Cancer with CAR T-Cell Therapy
Emily Whitehead was 6 years old and facing a life-threatening recurrence of acute lymphoblastic leukemia (ALL) when her parents enrolled her in a clinical trial at CHOP.
The trial would test the effectiveness of chimeric antigen receptor (CAR) T-cell therapy — a new type of immunotherapy engineered by researchers at the Perelman School of Medicine at the University of Pennsylvania in the late 1990s.
Under the care and oversight of Stephan Grupp, MD, PhD, Director of Translational Research at the Center for Childhood Cancer Research, Emily’s T cells were collected from her blood, genetically modified to produce a special CAR, then infused back into her body to find and attack cancer cells.
Stephan Grupp, MD, PhD
Stephan Grupp, MD, PhD, Director of Translational Research at the Center for Childhood Cancer Research
The treatment worked, and Emily’s treatment was deemed a “cure” in 2017, after she was cancer-free for 10 years.
“Having given those cells to her with my own hands, I felt this enormous sense of responsibility,” Dr. Grupp said.
The FDA approved the therapy, Kymriah® (tisagenlecleucel), in August 2017. Since then, more than 30,000 patients have undergone CAR T cell therapy, according to Penn Medicine, to treat a variety of blood cancers, including lymphoma, leukemia, and multiple myeloma.
At CHOP, researchers continue to explore ways to make it CAR T-cell therapy safer and more effective for a variety of diseases, including solid tumors.
First to Develop a Gene Therapy for an Inherited Disease
Lindsey George, MD
Lindsey George, MD, Director of CHOP's Clinical In Vivo Gene Therapy (CIGT) group
During the 1990s, Katherine A. High, MD, came to CHOP to investigate the potential of an in vivo gene therapy to cure hemophilia B, a blood-clotting disorder.
Dr. High and colleagues soon discovered that an adeno-associated virus (AAV) could be used to deliver the gene that would help the body produce an essential clotting factor.
Building off those findings and with support from CHOP leadership, Dr. High collaborated with researchers at Penn to develop a gene therapy for individuals with an inherited retinal dystrophy. In 2017, following clinical trials, the FDA approved Luxturna® (neparvovec-rzyl) — the first gene therapy for an inherited disorder. Their work has been awarded the prestigious Breakthrough Prize at the “Oscars of Science.”
Today, 32 in vivo gene therapy clinical trials are ongoing at CHOP, and in 2021, CHOP launched the CIGT, which is helping to transform preclinical discoveries into approved therapies. To date, the group has treated more than 1,000 patients, supported more than 175 clinical trials, and led to the development of four licensed gene therapy products.
First to Improve AAV Vectors
Beverly Davidson, PhD
Beverly Davidson, PhD, conducts tour of the Clinical Vector Core.
CHOP researchers also have played an important role in developing the next generation of vectors to improve AAV-based gene therapies.
During her decades-long tenure at CHOP, Dr. Davidson bridged basic vector engineering and clinical application to establish the preclinical foundation for gene therapies targeting neurodegenerative and other diseases.
Her laboratory pioneered the use of AAV vectors to deliver RNA interference (RNAi) and other gene-silencing molecules, enabling long-term suppression of gain of function disorders such as Huntington's disease and amyotrophic lateral sclerosis (ALS).
Dr. Davidson's research helped demonstrate how capsid design, promoter selection, and delivery approaches could improve cell-specific targeting and regulated expression, key factors in making gene therapies safer and more effective.
“From the beginning, I've been focused on the goal of engineering vectors that are more potent,” Dr. Davidson said. “This improves safety because it reduces the doses needed and has the added benefit of greatly lowering the costs of goods per patient. These features make the newer generations of vectors more accessible to patients.”
In 2026, the American Society of Gene and Cell Therapy honored Dr. Davidson with an Outstanding Achievement Award for her pioneering discoveries.
First to Treat Patient with Personalized Gene Editing
Rebecca Ahrens-Nicklas, MD
Baby KJ with Rebecca Ahrens-Nicklas, MD, PhD and Kiran Musunuru, MD, PhD
In a historic medical breakthrough, a CHOP-Penn team of researchers were the first in the world to treat a person with a customized, gene-editing treatment.
KJ Muldoon was born at the Hospital of the University of Pennsylvania in August 2024. Three days later, KJ was rushed to CHOP, where doctors suspected that a metabolic disorder could be causing his ammonia levels to spike.
The newborn’s medical team ordered a Rapid Targeted Analysis of the Genome-Infant (rTAG-I) — a test developed by researchers in CHOP’s Baby Eagle Initiative to identify rare diseases — and he was diagnosed with CPS1 deficiency syndrome. CPS1 encodes enzymes that the liver needs to convert ammonia into harmless urea. When ammonia builds up, it can cause permanent brain injury and even death.
Rebecca Ahrens-Nicklas, MD, PhD, Director of the Gene Therapy for Inherited Metabolic Disorders Frontier Program (GTIMD), offered KJ’s parents a potentially life-saving option: Their son could be the first patient in the world to receive an experimental gene-editing therapy tailored to his specific variant.
The treatment used a new type of CRISPR-based technology to rewrite specific DNA letters in an individual’s genome.
Today, KJ is healthy, and the team who treated him has received funding from the Advanced Research Projects Agency for Health (ARPA‑H) to expand the feasibility and scalability of the transformative approach to benefit the greater rare disease community.
“There are hundreds of millions of people living with rare diseases,” Dr. Ahrens-Nicklas said. “We’ve made it our mission since treating KJ to find a way to scale our approach, so many more patients will have access to this transformational technology.”to cure cancer that Alan's Legacy supports:
