Spark Therapeutics Updated SPK-8011 Data from Phase 1/2 Study Shows Multi-Year, Durable Factor VIII (FVIII) Expression that Significantly Reduced Bleeding in Hemophilia A Patients

Data from Spark Therapeutics’ Phase 1/2 gene therapy study published in New England Journal of Medicine

PHILADELPHIA, November 17, 2021 — Spark Therapeutics, a member of the Roche Group (SIX: RO, ROG; OTCQX: RHHBY) and a fully integrated, commercial gene therapy company dedicated to challenging the inevitability of genetic disease, today announced data from its Phase 1/2 clinical trial of investigational SPK-8011 in hemophilia A. The study found that, at a median efficacy follow-up of 33.4 months (range, 3.7-47.6), 16 of 18 study participants had sustained factor VIII (FVIII), which permitted prophylaxis cessation and reduction in bleeding episodes. The latest results were published online in the New England Journal of Medicine (NEJM).

The updated analysis (cutoff May 3, 2021) of all 18 study participants, following the initial data presentation at the International Society of Thrombosis and Hemostasis (ISTH) 2021 Virtual Congress in July, demonstrated a 91.5% reduction (95% CI: [88.8, 94.1]) in annualized bleed rate (ABR) and a 96.4% reduction (95% CI: [95.7, 97.1]) in annualized number of FVIII infusions.

“We are thrilled that the New England Journal of Medicine chose to publish data from our Phase 1/2 study of investigational SPK-8011 and highlight its potential for patients living with hemophilia A,” said Gallia Levy, M.D., Ph.D., Chief Medical Officer, Spark Therapeutics. “This Phase 1/2 study for SPK-8011 demonstrates our commitment to following the science to develop gene therapies for hemophilia A that demonstrate safety, predictability, efficacy and durability at the lowest effective dose and with an optimal immunomodulatory regimen.”

In the safety analysis, 33 treatment-related adverse events (AEs) occurred in 8 participants of which 17 were vector-related, including one serious AE, and 16 were glucocorticoid-related. As previously reported, two participants lost all FVIII expression due to an anti-AAV capsid cellular immune response, unresponsive to immunosuppression. The remaining 16 participants maintained FVIII expression, of which 12 were followed for over 2 years and demonstrated no apparent decrease in one-stage FVIII activity over time.

About SPK-8011 for hemophilia A

Investigational SPK-8011, a novel bio-engineered adeno-associated viral (AAV) vector utilizing the AAV-LK03 capsid, also referred to as Spark200, contains a codon-optimized human factor VIII gene under the control of a liver-specific promoter. The Food and Drug Administration (FDA) granted orphan-disease designation and breakthrough therapy designation in the U.S., while the European Commission has granted orphan designation to SPK-8011.

The Phase 1/2 study, titled “A Gene Transfer Study of SPK-8011 for Hemophilia A,” is being conducted by Spark Therapeutics, Inc. to determine the safety and efficacy of the factor VIII gene transfer treatment with SPK-8011 in individuals with hemophilia A. (Trial identifier NCT03003533)

About Roche and Spark Therapeutics gene therapy research in hemophilia A

We believe gene therapy has the potential to revolutionize medicine and improve the lives of patients with genetic and other serious diseases. Pairing Roche’s long-standing commitment to developing medicines in hemophilia with Spark Therapeutics’ proven gene therapy expertise brings together the best team of collaborators researching gene therapies in hemophilia A. It is our aligned objective to develop gene therapies for hemophilia A that, with the lowest effective dose and the optimal immunomodulatory regimen, demonstrate safety, predictability, efficacy, and durability for patients.

About Hemophilia A

Hemophilia is a rare genetic bleeding disorder that causes the blood to take a long time to clot because of a deficiency in one of several blood clotting factors. People living with hemophilia are at risk of excessive and recurrent bleeding spontaneously and from modest injuries, which have the potential to be life threatening. There are approximately 15,000 people with hemophilia A in the U.S. and 19,000 in the five major European countries. Hemophilia A is about four times as common as hemophilia B. Hemophilia A is characterized by mutations in the factor VIII gene (FVIII), which lead to deficient blood coagulation and an increased risk of bleeding or hemorrhaging. The current standard of care for hemophilia A requires recurrent intravenous infusions of either plasma-derived or recombinant factor VIII to control and prevent bleeding episodes. There exists a significant need for novel therapeutics to treat people living with hemophilia.

About Spark Therapeutics

At Spark Therapeutics, a fully integrated, commercial company committed to discovering, developing and delivering gene therapies, we challenge the inevitability of genetic diseases, including blindness, hemophilia, lysosomal storage disorders and neurodegenerative diseases. At Spark, a member of the Roche Group, we see the path to a world where no life is limited by genetic disease. For more information, visit, and follow us on Twitter and LinkedIn.

Media Contact:
Francesca Dellelci
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