Sangamo Therapeutics, Inc. recently announced positive preliminary data from the Phase 1/2 clinical trial designed to evaluate SB-525, the company’s gene therapy program for people with hemophilia A, or factor VIII (FVIII) deficiency. SB-525 is being developed as part of a global collaboration between Sangamo and Pfizer for the development and commercialization of hemophilia A gene therapy programs.

The trial is an open-label, dose-ranging clinical study designed to assess the safety and tolerability of SB-525 in up to 20 adults with severe hemophilia A. The investigational therapy is developed using adeno-associated viruses (AAVs) as delivery vehicles, or vectors, to carry the genetic codes that initiate the production of the deficient factor protein—in this case, FVIII in those with hemophilia A. The AAVs deliver this genetic material into liver cells, without causing disease or triggering significant immune responses.

In a new press release Sangamo reports that five patients have been treated with SB-525 at three different dose levels to date. A sixth patient is scheduled to receive the therapy in latter part of August of 2018. Preliminary observations have thus far shown SB-525 to be “generally well tolerated” with no treatment-related serious adverse events. They also report that a fifth patient was treated in June and has subsequently achieved therapeutic FVIII activity levels.

“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.”

Source: Sangamo press release dated August 8, 2018