FDA Grants Regenerative Medicine Advanced Therapy Designation to Experimental Wiskott-Aldrich Syndrome Drug

According to a press release from the British-American biopharmaceutical company Orchard Therapeutics, the American Food and Drug Administration (FDA) has granted OTL-103, the Company’s experimental Wiskott-Aldrich Syndrome drug, Regenerative Medicine Advanced Therapy (RMAT) designation.

About Wiskott-Aldrich Syndrome

Wiskott-Aldrich syndrome is a genetically-inherited condition characterized by immune system dysfunction and reduced blood clotting function.

The condition is caused by mutation to a gene called WASIn otherwise healthy individuals, WAS is responsible for coding the production of a protein called WASP, which is found in every blood cell. WASP actually takes its name after Wiskott-Aldrich syndrome, which should give you some idea of the gene’s importance in the disease. WASP plays an important role in cell signalling and the structure of the actin cytoskeleton — the collection of fibrous substances in the cytoplasm of cells that provides structure to the cell.

Patients with Wiskott-Aldrich syndrome have shortages of functioning blood cells of many varieties. Their white blood cells may be abnormal or absent entirely, resulting in frequent infections. Due to the weakness of the immune system in these patients, certain autoimmune disorders (such as rheumatoid arthritis) and types of cancer (such as lymphoma) are more common in individuals with Wiskott-Aldrich. The severe infections and bleeding episodes that characterize Wiskott-Aldrich can be fatal.

Wiskott-Aldrich is incredibly rare — thought to occur in only about ten in one million male births. Because the gene linked to the condition is located on the X chromosome, Wiskott-Aldrich is much more common in men than women. Men need only inherit one mutated copy of WAS to develop Wiskott-Aldrich. Women with only one mutated copy of WAS may have only mild symptoms of the condition, if at all. A woman with two mutated copies can theoretically develop full-strength Wiskott-Aldrich, though this would be exceptionally rare.

Without treatment, Wiskott-Aldrich is typically fatal within 20 years. However, recent advances in gene therapy have greatly improved survivability for most patients.

About OTL-103 and RMAT Designation

OTL-103 is an experimental ex vivo hematopoietic stem cell-based gene therapy. Blood stem cells are taken from the patient, genetically modified, then reintroduced to bring about physiological changes. It recently received RMAT designation from the FDA.

Regenerative Medicine Advanced Therapy (RMAT) designation is given to drugs that are “regenerative medicine therapies” that have the potential to treat, modify, or reverse the course of a serious disease. The designation is only available to products that show early promise to address unmet medical needs for said condition.

A phase 2 clinical study of the effects of OTL-103 is still recruiting, though researchers only estimate an enrollment of six or so participants. The trial is lengthy as well, with a planned end date around the end of 2022. Although progress may seem slow, it isn’t unusual for drugs in phase 2 study to take years before reaching market approval — if they ever do. Phase 2 studies are where most experimental drugs fail.

Only time will tell the true potential of OTL-103, though similar hematopoietic stem cell gene therapies are already an essential component in the treatment of Wiskott-Aldrich.


What do you think of this exciting news? Other gene therapies have had tremendous affect on the survivability of Wiskott-Aldrich. Does this improve your views about OTL-103? Share your thoughts with Patient Worthy!

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