Sangamo Announces Positive Preliminary Data from the Phase 1/2 Study Evaluating SB-525 Gene Therapy for Hemophilia A

RICHMOND, Calif., Aug. 8, 2018 /PRNewswire/ — Sangamo Therapeutics, Inc. (Nasdaq: SGMO) today announced positive preliminary data from the Phase 1/2 clinical trial evaluating SB-525, a cDNA gene therapy candidate for Hemophilia A (the “Alta study”). SB-525 is being developed as part of a global collaboration between Sangamo and Pfizer Inc. for the development and commercialization of potential gene therapy programs for Hemophilia A.

The Alta study is an open-label, dose-ranging clinical trial designed to assess the safety and tolerability of SB-525 in up to 20 adult subjects with severe Hemophilia A. To date, five patients have been treated at three dose levels. A sixth patient is scheduled for treatment later this month. During the initial dose escalation phase, this study enrolls two patients per dose cohort.

Preliminary Observations

  • In the Alta study, SB-525 has been generally well tolerated to date with no treatment-related serious adverse events and no use of tapering courses of oral steroids.
  • The fifth patient in the study, the first at the third dose level, was treated in June and has achieved therapeutic Factor VIII activity levels.*
  • A dose dependent effect has been observed in the study, with patients in the second dose cohort reporting reduced use of factor replacement.

Sangamo and Pfizer expect to present detailed data from the Alta study at a hematology conference in the fourth quarter.

“We have made good progress with dose escalation in this study and are encouraged by the safety and tolerability profile to date and by the attainment of therapeutic Factor VIII activity levels in the first patient in the third dose cohort,” said Edward Conner, MD, Chief Medical Officer of Sangamo. “We look forward to generating additional data to assess the consistency and sustainability of the Factor VIII expression observed.”

*Epidemiological data indicate that Factor VIII activity above 12% of normal is associated with substantial reduction or elimination of spontaneous bleeds and factor usage. Den Uijl IE et al Haemophilia 2011; 17(6):849-53

About SB-525

SB-525 comprises a recombinant adeno-associated virus (rAAV) vector carrying a Factor VIII gene construct driven by a proprietary, synthetic, liver-specific promoter. The U.S. Food and Drug Administration has granted Orphan Drug and Fast Track designations to SB-525, which also received Orphan Medicinal Product designation from the European Medicines Agency. Hemophilia A is a rare blood disorder caused by a genetic mutation resulting in insufficient activity of Factor VIII, a blood clotting protein the body uses to stop bleeding. There are approximately 16,000 patients in the U.S. and more than 150,000 worldwide with Hemophilia A.

About Sangamo

Sangamo Therapeutics is focused on translating ground-breaking science into genomic therapies that transform patients’ lives using the Company’s platform technologies in genome editing, gene therapy, gene regulation and cell therapy. For more information about Sangamo, visit

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