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Spark Therapeutics Announces Updated Phase 1/2 Study Results Supporting the Durability of Investigational Gene Therapy SPK-8011 in Patients With Hemophilia A

  • Multi-year data, with up to five years of follow up, show sustained expression of FVIII in more than 90% of participants, in addition to improved annual bleeding and infusion rates

  • Data shared during an oral presentation at ASH 2022

PHILADELPHIA, Dec. 12, 2022 (GLOBE NEWSWIRE) -- Spark Therapeutics, a member of the Roche Group (SIX: RO, ROG; OTCQX: RHHBY) and a fully integrated gene therapy company today announced updated multi-year results from its Phase 1/2 clinical trial of investigational SPK-8011 for patients with hemophilia A. With up to five years of follow-up, the data showed that a single infusion resulted in sustained factor VIII (FVIII) expression and clinically meaningful reductions in annualized bleed rate (ABR) and annualized FVIII infusion rates (AIRs). These data were presented at the 64th American Society of Hematology (ASH) annual meeting in New Orleans, La.

“The updated results of this Phase 1/2 study add to the growing body of preliminary evidence suggesting that investigational SPK-8011 provides durable FVIII expression for the treatment of hemophilia A,” said Gallia Levy, M.D., Ph.D., Chief Medical & Product Strategy Officer, Spark Therapeutics. “At Spark, we are focused on developing a gene therapy for people with hemophilia A that demonstrates safety, predictability, efficacy, and durability at the lowest effective dose with an optimal immunomodulatory regimen. This latest readout reinforces the potential for investigational SPK-8011 to deliver on our commitment, and we look forward to its continued evaluation.”

As of the data cutoff (Oct. 4, 2022), 21 of 23 (91%) participants across all dose cohorts experienced sustained expression of FVIII with up to five years of follow-up, including two participants who completed five years of follow-up. Of these 21 participants, the data showed a 92% (95% CI: 78-97%) reduction in ABR for all bleeds, with all-bleed ABR of 0.98 (95% CI: 0.46-2.08) post-infusion compared to 11.62 (95% CI: 7.42-18.19) pre-infusion. 16/21 (76%) participants had an ABR of <1 for treated bleeds and 19/21 (90%) had an ABR of <1 for spontaneous treated bleeds following investigational SPK-8011 infusion. Additionally, the data showed a significant reduction in FVIII concentrate consumption, with AIRs of 0.3 (0.0, 1.4) post-infusion compared to 85.5 (40.0, 104.0) pre-infusion.

In the updated safety analysis, there were no new safety signals reported related to investigational SPK-8011; no deaths, no thrombotic events, and no FVIII inhibitor development were reported. 11 participants experienced transient non-sustained asymptomatic ALT elevations during the expected window of presumed capsid immune response; all were mild except one participant who experienced a Grade 3 ALT elevation that was transient and asymptomatic. As previously disclosed, another participant experienced Grade 2 alanine transferase elevation, which qualified as a serious adverse event (SAE) and subsequently resolved, resulting in the only SAE related to investigational SPK-8011 to date. All ALT elevations were resolved with the use of immunomodulation agents. Two patients from the high dose cohort lost FVIII expression due to a presumed capsid immune response, as previously disclosed.

“For many individuals living with hemophilia A, current factor replacement therapies present limitations including the need for regular injections or infusions and unpredictable breakthrough bleeds,” said Stacey Croteau, study investigator and Medical Director, Boston Hemophilia Center. “We are encouraged by these data and the potential for investigational SPK-8011 to further improve on current standards of care by providing a one-time, durable treatment option, and we will continue with participant follow-ups.”

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. Interim results from the phase 1/2 study were published online in the New England Journal of Medicine (NEJM) in November 2021. 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 as part of our endeavor to create additional benefit beyond current treatment options.

About Hemophilia A
Hemophilia A is an inherited, serious disorder in which a person’s blood does not clot properly, leading to uncontrolled and often spontaneous bleeding. Hemophilia A affects around 900,000 people worldwide, approximately 35-39% of whom have a severe form of the disorder. People with hemophilia A either lack or do not have enough of a clotting protein called factor VIII. In a healthy person, when a bleed occurs, factor VIII brings together the clotting factors IXa and X, which is a critical step in the formation of a blood clot to help stop bleeding. Depending on the severity of their disorder, people with hemophilia A can bleed frequently, especially into their joints or muscles. These bleeds can present a significant health concern as they often cause pain and can lead to chronic swelling, deformity, reduced mobility and long-term joint damage. There exists a continued need for novel therapeutic options 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. Our focus includes ocular, systemic and neuroscience. 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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