A Study of Experimental Human Factor 8 Gene Therapy SB-525 For Severe Hemophilia A

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Age: 18 years or older
Healthy Volunteers: No
Keywords: Severe Hemophilia A, Hemophilia A, gene transfer, gene therapy, factor 8 gene therapy
Type: Biological study, Phase [/1/,/ /2/]
2 Participants
We invite you to take part in a research study because you have severe hemophilia A and you are a male, 18 years of age or older. Researchers want to find out more about an experimental drug called SB-525. An experimental drug is still being tested and is not approved for sale in the United States by the FDA. SB-525 belongs to a new class of treatment called gene therapy.

The main purpose of this study is to see if receiving SB-525 is safe and tolerable. Also, the potential effect of SB-525 for improving blood clotting will be evaluated.

SB-525 consists of substances called vectors (also referred to as carriers). Vectors carry a modified version of the gene for making Factor Eight clotting protein (FVIII). The drug is designed by Sangamo. Scientists think that SB-525 might help your body produce more FVIII.

The vector used in this study is a recombinant adeno-associated virus (AAV) that has been modified. These are viruses can infect humans but do not cause any known disease. These viruses are commonly-used vectors for gene transfer and have been changed in the laboratory. They can no longer grow or reproduce in the human body because most of their DNA has been removed and replaced with a gene coding for factor eight.

After a single infusion of SB-525 into a vein in your arm, the vector can go to the liver to introduce the gene for factor eight. The study team wants to find out if, after SB-525 infusion, your liver cells will produce FVIII protein and release it into your blood circulation.
This study requires

The study team will make sure you qualify to take part in the study. Qualified participants will receive detailed information about the study. This may include a list of study-related tests and procedures.

Who can participate

Inclusion criteria:

  • 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

Exclusion criteria:

  • 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
Benefits and risks of participating

We cannot promise any benefits to you as a result of taking part in this research study.


The study doctor will discuss the risks associated with taking part in this research study.
For your time and effort, you will be paid $50 per completed study visit. You will also receive $600 for the combined infusion day and 24-hour observation period following infusion.
Study duration and period
We expect that you will be in this research study for about 38 months. Upon completion of this study, you will be asked to take part in a separate long-term follow-up study. The follow-up study will track the possible long-term side effects of this gene transfer study.
Recruitment period
From May 20, 2018
UC Davis Medical Center
2315 Stockton Boulevard
Sacramento, CA 95817
Research Topic
  • Hemophilia A

Have any questions or want to learn more? Leave your contact details below and the research team will reach out to you.


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