A cooperative effort by researchers from the U.S. and the United Kingdom (UK) to develop a gene therapy for hemophilia B has resulted in a new phase of clinical development.

Netherlands-based Amsterdam Molecular Therapeutics (AMT), a company that specializes in gene therapy for different diseases and disorders, announced in March that the first patient has been dosed in a Phase I/II exploratory clinical trial with a gene therapy product for hemophilia B. The study includes the use of AMT’s proprietary gene therapy technology. The study uses a “vector-gene combination” that was developed at the St. Jude Children's Research Hospital in Memphis, TN. Arthur W. Nienhuis, MD, a faculty member at St Jude, is the principal investigator.

The gene therapy used in the trial employs adeno-associated viruses (AAV), small viruses that do not cause disease and produce mild immune responses, as vectors (delivery vehicles) to introduce a functioning factor IX (FIX) gene into the liver cells of subjects with hemophilia B. The goal of the trial is to trigger viable, long-term FIX protein production through a single administration of the therapy. This could reduce or even eliminate bleeding episodes in hemophilia B patients.

Earlier pre-clinical studies of FIX gene therapy were promising, demonstrating the potential for long-term FIX production at a significant level after a single treatment. Further, the efficacy was better than current treatments because the FIX remained stable, not demonstrating the peaks and troughs that occur with recombinant products now on the market.

The seminal work on this therapy was started more than a decade ago by St. Jude researchers Andrew Davidoff, MD, and Amit Nathwani, MD, PhD, now with the University College London (UCL). The current trial is a collaboration among St. Jude, UCL and a number of other institutions in the UK and the U.S.

“Dr. Andrew Davidoff and his group at St. Jude, together with Professor Nathwani in London, have done very important scientific work on hemophilia B,” said Jôrn Aldag, AMT CEO. “We are really looking forward to the results of the trial for continuing our collaboration, aiming for a real cure for patients with this bleeding disorder. Use of the factor IX gene fits perfectly with AMT’s proprietary gene therapy platform and our business strategy of developing cures for seriously debilitating orphan diseases.”

The purpose of the current trial, which has been approved by both the UK Medicines and Healthcare products Regulatory Agency and the U.S. Food and Drug Administration, is to measure the safety and efficacy of different doses of the therapy. After a successful trial, AMT will follow up with additional clinical studies to assess safety, tolerability and efficacy of AMT’s proprietary AAV-based gene therapy delivery systems.

AMT is developing AAV-based gene therapy products to treat Duchenne muscular dystrophy, acute intermittent porphyria (a metabolic disorder affecting hemoglobin) and Parkinson’s disease.   

Source: Medical News Today, March 11, 2010