Applications for the orphan medicinal product designation (OMPD) of 2 of Sangamo’s potential rare disease therapies have received positive opinions from the Committee for Orphan Medicinal Products of the European Medicines Agency (EMA).
The two product candidates, SB-318 and SB-913, are intended to treat the rare lysosomal storage disorders Mucopolysaccharidosis Type I (MPS I; Hurler syndrome) and MPS II (Hunter syndrome), respectively. Both were granted Orphan Drug Designation by the U.S. Food and Drug Administration for their particular indications in the first quarter of 2017.
MPS I and MPS II are caused by mutations in the genes responsible for encoding the alpha-L-iduronidase (IDUA) and iduronate 2-sulfatase (IDS) enzymes. Both SB-318 and SB-913 utilize Sangamo’s zinc finger nuclease (ZFN) genome-editing technology to provide stable, continuous production of these enzymes for the lifetime of the patient.
The ZFN-mediated in vivo
genome-editing tactic is devised to permit a patient’s liver to permanently produce circulating therapeutic levels of a corrective protein. It makes use of the endogenous albumin gene locus, a highly-expressing and liver-specific site that can be edited with ZFNs, to accept and express therapeutic genes.
The European Union’s (EU) OPMD is designed similarly to the Orphan Drug Designation in the U.S. It is granted to medicines proposed for the treatment, prevention or diagnosis of life-threatening or chronically debilitating conditions that are rare in the EU, defined as less than 5 in 10,000 persons.
Sangamo is also planning for SB-318 to be tested in clinical trials for the treatment of MPS II and hemophilia B.
In addition to the Orphan Drug Designations that were granted for the drugs in the U.S., both SB-318 and SB-913 have been granted Fast Track and Rare Pediatric Disease designations from the FDA. The Phase 1/2 clinical trials for these programs, evaluating the drugs in adults with the two variations of MPS are open and enrolling subjects.
At birth, infants with MPS I appear normal but may have inguinal and umbilical hernias. The diagnosis is most commonly made between 6 and 24 months of age after the condition begins to present via symptoms like developmental delays and skeletal abnormalities, among others. MPS I affects males and females equally with an incidence of about 1 in 100,000 births.
MPS II typically presents in patients between ages 2 and 4 years via symptoms like full lips, large rounded cheeks, a broad nose, and an enlarged tongue. By age 5, patients experience slow growth and joint deformities and affect mobility. Per the NIH
, it occurs in an estimated 1 in 135,000 males.
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