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for males ages 18 years and up (full criteria)
at San Francisco, California and other locations
study started
estimated completion:



The purpose of the study is to evaluate the safety, tolerability and time-course profile of FVIII activity levels with adaptive doses of SB-525.

Official Title

A Phase 1/2, Open-Label, Adaptive, Dose-Ranging Study to Assess the Safety and Tolerability of SB-525 (Recombinant AAV2/6 Human Factor 8 Gene Therapy) in Adult Subjects With Severe Hemophilia A


The objective of the study is to reduce or eliminate the need for FVIII replacement therapy. The proposed SB-525 clinical study uses a recombinant adeno-associated virus 2/6 (AAV2/6) vector encoding the cDNA for the B-domain deleted human F8 (hF8). The secreted FVIII has the same amino acid sequence as approved recombinant anti hemophilic factors (Refacto® and Xyntha®). The SB-525 vector encodes a liver-specific promotor module and AAV2/6 exhibits liver tropism, thus providing the potential for long-term hepatic production of FVIII in hemophilia A subjects.

The constant production of FVIII after a single SB-525 administration may provide potential benefit in durable protection against bleeding and the complications thereof without lifelong repetitive IV factor replacement administration.


Hemophilia A Factor VIII


You can join if…

Open to males ages 18 years and up

  • Male ≥18 years of age
  • Severe hemophilia A (past evidence of circulating FVIII activity of < 1% normal)
  • Treated or exposed to FVIII concentrates or cryoprecipitate for at least 150 exposure days
  • ≥12 bleeding episodes if receiving on-demand therapy over the preceding 12 months
  • Agree to use double barrier contraceptive until at least 3 consecutive semen samples are negative for AAV 2/6 after SB-525 infusion

You CAN'T join if...

  • Presence of neutralizing antibodies
  • Current inhibitor, or history of FVIII inhibitor (except for transient low titer inhibitor detected in childhood)
  • History of hypersensitivity response to FVIII
  • History of Hepatitis B or HIV-1/2 infection
  • History of Hepatitis C, unless viral assays in two samples, collected at least 6 months apart, are negative
  • Evidence of any bleeding disorder in addition to hemophilia A
  • Markers of hepatic inflammation or overt or occult cirrhosis
  • History of chronic renal disease or creatinine ≥ 1.5 mg/dL
  • Presence of liver mass on magnetic resonance imaging (MRI), or, positive alpha fetoprotein
  • Presence of > grade 2 liver fibrosis on elastography for subjects with history of treated Hepatitis C or suspicion of chronic liver disease


  • University of California, San Francisco accepting new patients
    San Francisco, California, 94117, United States
  • City of Hope National Medical Center accepting new patients
    Duarte, California, 91010, United States


accepting new patients
Start Date
Completion Date
Sangamo Therapeutics
Phase 1/2
Lead Scientist
Andrew Leavitt
Study Type
Last Updated
January 19, 2018
I’m interested in this study!