Sangamo Therapeutics (Nasdaq: SGMO) today announced treatment of its first patient in the Phase 1/2 clinical trial evaluating an investigational in vivo genome editing therapy for people with mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome.
For the first time, a patient has received a therapy intended to precisely edit the DNA of cells directly inside the body. We are at the start of a new frontier of genomic medicine.
– Dr. Sandy Macrae, CEO of Sangamo Therapeutics
Source: Associated Press
According to the Associated Press, the first recipient of the experimental therapy, called SB-913, was 44-year-old Brian Madeux. “It’s kind of humbling” to be the first to test this, said Mr. Madeux. “I’m willing to take that risk. Hopefully it will help me and other people.” He has had 26 operations for hernias, bunions, bones pinching his spinal column, and ear, eye and gall bladder problems. Last year he nearly died from a bronchitis and pneumonia attack. The disease had warped his airway, and Mr. Madeux was essentially drowning in his own secretions. Gene editing won’t fix damage he’s already suffered, but he hopes it will stop the need for weekly enzyme treatments.
Sangamo aims to treat MPS II by using genome editing to insert a corrective gene into a precise location in the DNA of liver cells with the goal of enabling a patient’s liver to produce a lifelong and stable supply of an enzyme he or she currently lacks. Without this enzyme, called iduronate-2-sulfatase (IDS), people with MPS II suffer debilitating buildup of toxic carbohydrates in cells throughout their body. Approximately one in 100,000 to one in 170,000 people are born with MPS II, many of whom receive weekly infusions of enzyme replacement therapy (ERT), the current standard-of-care treatment. Within a day of receiving ERT, however, IDS quickly returns to near undetectable levels in the blood.
SB-913 makes use of Sangamo’s zinc finger nuclease (ZFN) genome editing technology to insert a corrective gene into a precise location in the DNA of liver cells. To restrict editing to liver cells, the ZFNs and the corrective gene are delivered in a single intravenous infusion using adeno-associated virus (AAV) vectors that target the liver. The ZFNs enter the cells as inactive DNA instructions in a format designed only for liver cells to unlock. Once “unlocked”, the ZFNs then identify, bind to and cut the DNA in a specific location within the albumin gene. Using the cells’ natural DNA repair processes, liver cells can then insert the corrective gene for IDS at that precise location.
Two additional clinical trials are underway in the United States to evaluate Sangamo’s in vivo genome editing therapeutics for hemophilia B and MPS I, which is also known as Hurler or Hurler-Scheie syndrome. All three trials use ZFNs designed to edit liver cells at the same location in the albumin gene, but differ in delivering the corrective gene relevant to the respective disease.
As a physician, I feel a real sense of responsibility toward the patients who are participating in these three clinical trials. We have been working closely with the FDA and the NIH Recombinant DNA Advisory Committee to make sure that we are thoroughly and prudently developing this new class of medicines.
– Ed Conner, MD, chief medical officer of Sangamo.
All three of Sangamo’s in vivo genome editing product candidates have received Fast Track and Orphan Drug designations from the FDA. Additionally, SB-318, a compound that Sangamo is developing for MPS type I, and SB-913 have received the FDA’s Rare Pediatric Disease designation.
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