SB-525 delivers a human factor VIII cDNA construct and synthetic liver-specific promoter to the cell’s nucleus by using recombinant adeno-associated virus (rAAV). The drug — created specifically as a single-time treatment — provides a continuous expression of factor VIII protein and works by replacing a defective gene with a functioning copy of that gene.
The genetic material can be delivered in a number of ways but the most common option is using a viral vector, like rAAV. Gene therapy could potentially transform the treatment of hemophilia A patients, as it offers a highly targeted dose that addresses the root cause of the disease.
“We believe SB-525 has the potential to be a best-in-class therapy that may provide patients with stable and durable levels of factor VIII protein with a single administration treatment,” Dr. Mikael Dolsten, Pfizer’s president of worldwide research and development at Pfizer, said in announcing the global agreement.
The FDA’s fast-track designation will speed up SB-525’s development and expedite its review process of a new drug. Sangamo had already received the agency’s orphan drug designation for SB-525 earlier this month. In addition, the FDA has approved Sangamo’s application for investigational new drug status. A Phase 1/2 clinical trial (NCT03061201) evaluating the gene therapy in adults with hemophilia A will likely start enrolling patients soon, with data expected in late 2017 or early 2018.
Under the agreement, Sangamo will receive an upfront payment from Pfizer to conduct the Phase 1/2 upcoming trial. Pfizer will be responsible for all subsequent research, development and commercialization activities.
“Early data shows that we may be entering a new era in treating hemophilia — not by simply replacing the missing factor up to a couple of times a week, but with a single treatment providing a correct version of the gene that may then produce curative levels of factor for life,” Greg LaRosa, who leads Pfizer’s Rare Disease Research Unit, said in a dedicated article.