First U.S. Gene Therapy Clinical Trial to treat Choroideremia initiated in Philadelphia

Dr. Jean BennettSpark Therapeutics, a late-stage gene therapy company developing treatments for debilitating, genetic diseases, announced today it has initiated a Phase 1/2 clinical trial for the potential treatment of patients with choroideremia (CHM) utilizing its gene therapy product SPK-CHM.  The Phase 1/2 trial is an open-label, dose-escalating trial designed to assess the safety and preliminary efficacy of sub-retinal administration of SPK-CHM. The Phase 1/2 trial will be conducted at The Children’s Hospital of Philadelphia (CHOP) and the University of Pennsylvania, and has plans to enroll up to 10 patients afflicted with the CHM genetic mutation.


“Spark’s groundbreaking announcement today brings real hope of a cure for blindness caused by choroideremia, and promises to pave the way for treatments of other retinal diseases impacting millions of people around the World,” said Dr. Chris Moen, President of the Choroideremia Research Foundation, the leading advocacy and fundraising organization focused on finding a cure for CHM.  “The Choroideremia Research Foundation is proud to have provided preclinical funding to Jean Bennett, MD, PhD, and her team at the Perelman School of Medicine at the University of Pennsylvania, that has helped bring us to the gene therapy human clinical trials being announced today.”


Dr. Jean Bennett’s preclinical work, which was funded in part by consistent financial support from the Choroideremia Research Foundation (, demonstrated the ability of the SPK-CHM gene therapy to restore REP-1 protein production, membrane trafficking and retinal structure.


“Throughout my career’s work developing genetic therapies for inherited retinal dystrophies I have had my target set on a number of different conditions, in particular, choroideremia,” said Dr. Bennett, who is also one of Spark’s scientific co-founders and a scientific advisor on the SPK-RPE65 clinical trials being conducted at CHOP. “The SPK-CHM program, for the first time, creates the potential for patients to use their vision for longer and see more things.”


In addition to evaluating safety, the trial will help define the dose required to achieve stable or improved visual function and identify appropriate endpoints for subsequent clinical trials. With SPK-CHM, Spark is leveraging the experience and technology utilized in the development of its gene therapy for Leber’s congenital amaurosis (LCA), SPK-RPE65, including the same vector, target cells and route of administration, as well as the same manufacturing process.  SPK-RPE65 is currently in a fully-enrolled pivotal Phase 3 clinical trial.


CHM is an X-linked inherited retinal dystrophy which manifests in affected males in childhood as night blindness and a reduction of visual field, followed by progressive constriction of visual fields, ultimately leading to complete blindness.  CHM affects an estimated 1 in 50,000 males in the United States and there is currently no approved treatment for the disease.


For more information on Choroideremia and the Choroideremia Research Foundation (CRF), visit


For more information on Spark and its pipeline of gene therapy candidates please visit

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The Choroideremia Research Foundation Inc. is an international, non-profit organization dedicated to raising funds to find a treatment or cure for Choroideremia, a rare inherited retinal degenerative disease that causes blindness.

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