Dr. Donald Cohn has been developing gene therapies for rare immune diseases in children for more than 30 years. This week, his role in clinical trials culminated in the first-ever U.S. Food and Drug Administration-approved treatment for severe leukocyte adhesion deficiency-I, a genetic disease characterized by recurrent infections and often early death.
This rare childhood disease affects approximately 1 in 1 million children worldwide. Mutations in the ITGB2 gene disrupt the normal function of CD11 and CD18, two proteins that work together to help white blood cells reach and respond to infections. When this process is disrupted, children are susceptible to recurring life-threatening bacterial and fungal infections. Without treatment, survival beyond childhood is rare.
The treatment’s approval, sold under the name Cressradi, was based on the results of a clinical trial led at UCLA by Cohn, a member of the Eli Edith Broad Center for Regenerative Medicine and Stem Cell Research.
Seeing these patients yearly for follow-up and seeing that they are no longer battling a life-threatening infection is extremely rewarding. ”
Researchers enrolled nine patients with severe LAD-I from around the world between the ages of 5 months and 9 years. The small cohort reflects the rarity of this condition. Of the nine patients, the UCLA team enrolled and treated six. The three received treatment in London and Spain.
The clinical trial was conducted in collaboration with UCLA researchers and Rocket Pharmaceuticals, which sponsored the study.
Gene therapy using the patient’s own cells
The one-time gene therapy works by adding a healthy copy of the ITGB2 gene to each child’s blood stem cells and returning these cells to that child, allowing their bodies to produce functional immune cells to fight infections and heal wounds faster. By using the patient’s own cells, this treatment avoids the risks of immune system rejection and graft-versus-host disease associated with donor cells.
For the patients we treated, this therapy was found to have fewer short- and long-term toxicities than those often associated with bone marrow transplants, which require more chemotherapy and immunosuppressants before and after the transplant. ”
Dr. Donald Cohn, member of the Eli Edith Broad Center for Regenerative Medicine and Stem Cell Research
All nine trial patients survived without the need for bone marrow transplantation, and no cases of graft failure or immune rejection were reported. Importantly, the data shows a significant reduction in serious infections requiring hospitalization.
The children’s pre-treatment high white blood cell counts, or leukocytosis, consistently improved, and the researchers observed the continued presence of the therapeutic gene and increased expression of CD18 and CD11a, which are important for immune system function.
From Decades of Research to FDA Approval
The news marks a major milestone for Cohn, who has spent more than 30 years developing and testing gene therapies for immune diseases. Cressradi is the first of these treatments that Cohn has been involved with to receive FDA approval. This is an important step to ensure that treatments reach patients who need them.
The treatment, developed by Rocket Pharmaceuticals, is expected to become available through specialized treatment centers experienced in in vitro gene therapy procedures. Confirmation of clinical benefit will be based on evaluation of long-term follow-up data of treated patients through clinical studies and post-marketing registration.
The approval is also a major victory for the California Institute for Regenerative Medicine (CIRM), a California agency that funds stem cell and gene therapy research. Founded in 2004 to advance stem cell therapies, CIRM collaborated with Rocket to co-fund gene therapy clinical trials and is currently celebrating the first-ever FDA approval made possible by its support.
Cohn is optimistic that the approval will encourage more companies to develop treatments for other rare diseases. He is conducting a clinical trial testing a treatment for another deadly immune system disease known as ADA-SCID (Adenosine Deaminase Deficiency Severe Combined Immunodeficiency). The results were equally encouraging, with long-term follow-up data published in NEJM in October 2025 showing a 95% success rate among the 62 children treated, with no serious complications reported.
“We hope that approvals like this will encourage other companies to invest in these types of treatments and recognize that there is a path to commercializing these treatments,” Cohn said. “We have reached a point where it is not science, but rather commercial investment, that is preventing these treatments from becoming more available. This could help turn the tide.”
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University of California, Los Angeles Health Sciences
