Clinical Data
Hemophilia B Data OverviewSPK-9001, a novel bio-engineered adeno-associated virus (AAV) capsid expressing a codon-optimized, high-activity human factor IX variant, was developed using Spark's proprietary technology platform for selecting, designing, manufacturing and formulating highly optimized gene therapies.  SPK-9001 is being developed in collaboration withPfizer Inc. (NYSE:PFE). Data from the Phase 1/2 clinical trial of SPK-9001 were presented on June 11 at the 21stCongress European Hematology Association (EHA) by Dr. Spencer Sullivan, an Assistant Professor of Pediatrics and Medicine at the University of Mississippi Medical Center and a trial investigator, and were an extension of the data released on May 19th in the initial EHA abstract.Data presented today show that the low dose cohort of four subjects enrolled in the study experienced consistent and sustained factor IX activity levels following a single administration of SPK-9001 at the initial dose level (5 x 1011vg/kg) studied in the trial. Factor IX activity in the first two subjects, which had no history of liver disease, rose consistently and have stabilized at 28% of normal through the first approximately twenty-six weeks post-administration in the first subject, and at 41% of normal at fifteen weeks post-administration in the second. Factor IX activity level in the third subject, with a history of liver disease, also rose consistently and was at 26% of normal at approximately ten weeks post-administration. The fourth subject, also with a history of liver disease and not included in the previously disclosed data, saw a clinical response similar to the earlier subjects and was at 33% of normal through approximately seven weeks.To date, over a combined 58 weeks of observation, none of the first four subjects received regular infusions of factor IX concentrates to prevent bleeding events. One precautionary infusion took place due to a suspected ankle bleed in subject number three two days after administration. Based on their pre-enrollment histories, it is estimated that the four subjects followed to date would have received more than 100 infusions of recombinant factor IX over the period of the study to prevent or treat bleeds as part of their normal care.Across the cohort, we saw no sustained elevation in liver enzyme levels and no drop in factor IX levels. To date,SPK-9001 has been well-tolerated and no subjects have needed, or received, immunosuppression.Hemophilia A ProgramSpark today highlighted preclinical results from SPK-8011, the lead investigational candidate in its SPK-FVIII program for hemophilia A.  SPK-8011 was developed using Spark's proprietary technology platform and uses Spark200, a novel bio-engineered adeno-associated virus (AAV) capsid optimized for more efficient transduction of human hepatocytes, and contains an optimized B-domain deleted FVIII expression cassette. Spark retains global commercialization rights to its SPK-FVIII program for hemophilia A.Data presented at the meeting of the American Society of Gene and Cell Therapy in May demonstrated strong preclinical data, specifically FVIII expression in the 15% to 35% range in preclinical models at clinically relevant doses of 2 x 1012 vg/kg.Today, the company released additional preclinical data, utilizing an in vitro assay, of the Spark200 capsid demonstrated higher efficiency in transducing human hepatocytes compared to Spark100, the capsid used in SPK-9001.