Dimension Therapeutics Reports Preclinical Data Showing Ongoing DTX101 Phase 1/2 Trial at ASGCT Meeting

Dimension Therapeutics, Inc. DMTX, a biopharmaceutical company advancing novel, adeno-associated virus (AAV) gene therapies targeting the liver, a central organ for devastating rare diseases, today announced positive preclinical results supporting Dimension's ongoing Phase 1/2 clinical trial of lead candidate DTX101, which commenced in January 2016. DTX101 is designed to deliver Factor IX, or FIX, gene expression, in adult patients with moderate/severe to severe hemophilia B. Preclinical research conducted with Dimension's collaborators at the University of Pennsylvania (PENN) demonstrated dose-dependent expression of FIX levels and stability of FIX expression after single dose administration across the majority of doses during the 90-day study period. The study also found there were no apparent safety concerns related to the anticipated clinical dosing. These findings were highlighted in a poster, titled "A Dose-Escalating Preclinical Study to Determine the Efficacy, MED, and Safety of a Clinical Candidate Vector in a Mouse Model of Hemophilia B" (Abstract No. 227), presented at the 19th ASGCT Annual Meeting, which is taking place in Washington, DC, May 4-7, 2016. "In DTX101, we have pre-clinically developed a potent AAVrh10 vector containing a wild-type FIX gene with the goal of achieving approximately 10 percent of normal FIX levels, which we hope will ultimately lead to the achievement of clinically meaningful benefits for patients via gene delivery," said James M. Wilson, MD, PhD, a professor of Medicine and Pediatrics, and director of the Orphan Disease Center at the Perelman School of Medicine at the University of Pennsylvania. "Our preclinical data provides supporting evidence for this, both in terms of durability and consistent, dose-dependent activity of DTX101, as well as promising initial safety findings. We look forward to the continued progress of the clinical program, which is expected to report interim topline data later this year." Lili Wang, PhD, a research associate professor in the Wilson lab, is first author on this poster presentation. Dimension's phase 1/2 clinical trial of DTX101 is a single arm, open-label, multi-center study, designed to evaluate the safety, dose and early efficacy of DTX101 in adult patients with moderate/severe to severe hemophilia B. Additional information about Dimension's Phase 1/2 study of DTX101 may be found at ClinicalTrials.gov, using Identifier NCT: NCT02618915. "Dimension's presentations at this week's ASGCT conference, as well as at other important medical and scientific conferences throughout this year, demonstrate our commitment to generating and communicating important data that enables the translation of gene therapy science into the clinic," said Annalisa Jenkins, MBBS, MRCP, Chief Executive Officer of Dimension. "Based on breakthrough AAV technology and key collaborations, as with PENN, we continue to advance our leading portfolio in liver-associated diseases –hemophilia and inherited metabolic diseases – to meet compelling needs for patients." PENN and Wilson are each holders of Dimension stock and Wilson also holds stock in REGENXBIO, Inc. Dimension holds exclusive sublicenses from REGENXBIO, Inc. for certain PENN-owned AAV technologies related to this development program.