Image by Spencer Phillips
The US Food and Drug Administration (FDA) has granted orphan drug designation to SB-FIX, a zinc finger nuclease (ZFN)-mediated genome-editing product candidate for the treatment of hemophilia B.
SB-FIX is designed to be used as a one-time treatment that will provide stable, continuous production of factor IX (FIX) for the lifetime of the patient.
The ZFN-mediated in vivo genome-editing approach makes use of the albumin gene locus, a highly expressing and liver-specific genomic “safe-harbor site,” that can be edited with ZFNs to accept and express therapeutic genes.
The approach is designed is to enable the patient’s liver to permanently produce circulating therapeutic levels of a corrective protein product.
This differs from conventional adeno-associated virus complementary DNA gene therapy approaches, which are non-integrating and may “wash out” of the liver as cells divide and turn over.
Sangamo BioSciences, Inc., the company developing SB-FIX, expects to initiate a phase 1/2 trial of SB-FIX in adults with hemophilia B this year.
“We will enroll adult hemophilia patients into our first clinical trial. However, our goal is to move into pediatric patients, a population we believe could particularly benefit from a treatment that has the potential to provide life-long expression of therapeutic levels of factor IX protein,” said Geoff Nichol, MBChB, Sangamo’s executive vice president of research and development.
About orphan designation
The FDA grants orphan designation to drugs and biologics intended to treat, diagnose, or prevent diseases/disorders that affect fewer than 200,000 people in the US.
The designation provides incentives for sponsors to develop products for rare diseases. This may include tax credits toward the cost of clinical trials, prescription drug user fee waivers, and 7 years of market exclusivity if the product is approved.
