The Medicines and Healthcare Products Regulatory Agency (MHRA) has granted permission for initiation of Europe's first in vivo genome editing study.

The Clinical Trial Authorisation (CTA) paves the way for patient enrollment in an ongoing Phase I/II clinical trial evaluating Sangamo’s SB-FIX, a zinc finger nuclease (ZFN)-mediated in vivo genome editing treatment for hemophilia B.

Sangamo’s technology enables insertion of 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 the Factor IX protein.

The ZFNs and the corrective gene are delivered in a single intravenous infusion using AAV vectors that target only the liver. Once "unlocked" inside liver cells, 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 Factor IX at that precise location, the firm noted.

SB-FIX will be evaluated in both adults and adolescents. Sangamo said once preliminary safety and efficacy have been showed in the ongoing SB-FIX Phase I/II clinical trial in adults (18 years or older), it may then begin enrolling adolescents (12 – 17 years of age) into the study.

"Patients with hemophilia B need improved treatment options, and we are pleased to have rapidly reached agreement with the MHRA to expand the SB-FIX clinical trial to sites in the United Kingdom," said Edward Conner, Sangamo's chief medical officer.

"In vivo genome editing aims to provide a life-long therapeutic solution for certain genetic diseases. We believe the greatest value for this approach is in the treatment of children, and our goal with this study is to accumulate safety and efficacy data supporting progression of clinical trials into younger patient populations."

The firm is expecting to initiat sites in the UK later this year for the trial, and to file additional CTAs for its SB-318 and SB-913 in vivo genome editing treatments for Mucopolysaccharidosis Type I (MPS I) and MPS II, respectively.