Spark has announced updated multi-year results from its phase 1/2 clinical trial of SPK-8011, the company’s investigational gene therapy for hemophilia A. The results were presented at the recently concluded 64th American Society of Hematology (ASH) annual meeting in New Orleans, Louisiana.

Administered via a one-time intravenous infusion, SPK-8011 is designed to elicit  the production of therapeutic levels of the factor VIII (FVIII) protein in individuals with hemophilia A. Spark’s proprietary bioengineered adeno-associated virus (AAV) vectors carry the genetic codes that help generate FVIII. The approach being tested in this trial uses a modified novel AAV vector genome to deliver the corrected FVIII gene into liver cells where the protein is normally generated.

A Spark press release detailed the results that were presented at ASH, the primary focus of which were annualized bleed rate (ABR) and annualized FVIII infusion rates (AIRs) achieved by participants. As of the data cutoff (Oct. 4, 2022), 21 of 23 (91%) dosed 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% reduction in ABR for all bleeds, with all-bleed ABR of 0.98 post-infusion compared to 11.62 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.

The data also showed a significant reduction in FVIII replacement product usage,  with AIRs of 0.3 post-infusion compared to 85.5 pre-infusion. The company also reported that there were no new safety signals reported related to investigational SPK-8011; no deaths, no thrombotic events, and no FVIII inhibitor development were reported.

“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.”

Source: Spark press release dated December 12, 2022