A critical mission of our center is to bring novel therapies to the affected patients. We structured our center to facilitate translational research into clinical trials with speed and caution. We have collaborated on and assisted with developing multiple ocular gene therapy INDs, documents required by the FDA before initiating a clinical trial. In particular, our collaborative work on Leber’s Congenital Amaurosis type 2 (LCA caused by RPE65 mutations) with the Children’s Hospital of Philadelphia (CHOP) has resulted in the only Phase 3 gene therapy study currently underway in the world.

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CHM

Choroideremia

Choroideremia (CHM) is a rare inherited disorder that causes progressive loss

of vision due to degeneration of the choroid and retina. It affects about 1 in 50,000

males and the first symptom of these individuals is usually difficulty seeing at night or in

dim environments. These individuals gradually and progressively lose their side vision

and often become legally blind in young adulthood. The condition is passed through

families by an X-linked pattern of inheritance. This means that females (who have two

X chromosomes) can carry one “bad” choroideremia gene but usually do not have the

full-blown condition since they also carry a “good” gene. Since males only have one X

chromosome, they are more vulnerable: if they receive the chromosome with the “bad”

gene, they will develop the condition.

 

The mutation in the choroideremia gene causes a lack of RAB Escort Protein-1 (REP-1).

Our group, teamed with that of Dr. M. Seabra, was involved in some of the first attempts

to correct the condition using gene therapy1. In the past few years, work from our group

has optimized a gene therapy reagent which could deliver the normal gene safely and

efficiently to diseased retinal cells. Further, we have developed an induced pluripotent

stem (iPS) cell model2 that we used to demonstrate that our reagent can correct

the choroideremia defect. This has paved a path to develop a gene therapy clinical trial.

 

One of the requirements for enrollment in the trial will be a molecular diagnosis of

the choroideremia mutation. Individuals affected with choroideremia can undergo genetic

testing for choroideremia mutations through the Carver Lab. Carriers can also undergo

testing, however carriers will not be included in the first cohorts of subjects in the clinical

trial. Instructions for ordering the test can be found at:

https://www.carverlab.org/request/patient . 

 

If you have any questions about the on-going CHM trial, please contact: 

Denise Pearson at [email protected].

 

References

  1. Anand V, Barral DC, Zeng Y, Brunsmann F, Maguire AM, Seabra MC, Bennett J. Vision Res. 2003 Apr;43(8):919-26. Gene therapy for choroideremia: in vitro rescue mediated by recombinant adenovirus.
  2. Vasireddy V, Mills JA, Gaddameedi R, Basner-Tschakarjan E, Kohnke M, Black AD, Alexandrov K, Zhou S, Maguire AM, Chung DC, Mac H, Sullivan L, Gadue P, Bennicelli JL, French DL, Bennett J. PLoS One. 2013 May 7;8(5):e61396. AAV-mediated gene therapy for choroideremia: preclinical studies in personalized models.

Press

CAROT launches the CHM trial, using AAV gene therapy as a treatment for Choroideremia @ UPENN & Children's Hospital of Philadelphia. The study is led by Drs. Maguire, MD (PI) and Tomas Aleman, MD (Co-PI) from CAROT. For more information please contact Ms. Denise Pearson: [email protected].