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Spark Sees Continued Progress in Hemophilia B Gene Therapy

May 23, 2018
Spark Sees Continued Progress in Hemophilia B Gene Therapy

Spark Therapeutics and Pfizer recently announced that SPK-9001, an investigational gene therapy for individuals with hemophilia B, continues to perform well in an ongoing phase I/II clinical trial. Spark is developing SPK-9011 in collaboration with Pfizer Inc., as part of a program first established in 2014 to develop and commercialize novel gene therapy-based treatments for hemophilia B.

SPK-9001 is designed with Spark’s proprietary bioengineered adeno-associated viruses (AAVs), which act as delivery vehicles, or vectors, to carry the genetic codes that stimulate FIX production. The therapeutic approach being evaluated in this trial uses a modified novel AAV vector to deliver the corrected FIX gene into liver cells where the protein is normally generated.

Patients enrolled in the phase I/II trial received a single administration of SPK-9001. According to a Spark press release, in a cumulative follow-up of more than 18 patient years of observation (5 to 121 weeks), all 15 participants in the trial had discontinued routine infusions of factor IX concentrates. Based on individual patient history for the year prior to the study, the overall annualized bleeding rate for all 15 participants was reduced by 98% to an annual rate of 0.2 bleeds per patient, compared to an annual rate of 8.9 bleeds prior to delivery of SPK-9001. One participant experienced a bleeding event four or more weeks after SPK-9001 administration

Overall annual infusion rate was reduced by 99% for all 15 participants to an annual rate of 0.9 infusions, compared to an annual rate of 57.2 infusions prior to receiving SPK-9001. Six patients received factor IX infusions following SPK-9001 administration: two for reported spontaneous bleeds, two prior to surgery, one at the end of the study (discretionary, per protocol) and one for prophylaxis for a minor traumatic non-bleeding event. In addition, none of the 15 participants experienced serious adverse events and there were no thrombotic events or factor IX inhibitors reported, as of the May 7, 2018 data cutoff.

“We are pleased to see all 15 participants, notably including the first four participants who have been followed for more than two years, continue to show that a single administration of SPK-9001 has resulted in dramatic reductions in bleeding and factor IX infusions, with no serious adverse events,” said Katherine A. High, MD, president and head of research & development at Spark Therapeutics. “Our commitment to gene therapy research across our hemophilia programs remains steadfast with the goal of developing a novel therapeutic approach with a positive benefit-risk profile that aims to free patients of the need for regular infusions, while eliminating spontaneous bleeding.”

The trial data were presented at a session of the World Federation of Hemophilia 2018 World Congress, held May 20-24 in Glasgow, Scotland.

Source: Spark press release dated May 22, 2018