By: Carolyn A. Wilson, Ph.D.
In my last blog post I discussed aspects of regulatory science, that is, how scientists in FDA’s Center for Biologics Evaluation and Research (CBER) help to turn innovative medical research into life-saving or life-enhancing biological products. I also described how FDA scientists help determine if potential health problems are linked to the use of a particular medical product. In this post, I’ll discuss two more studies that made important contributions to public health.
Sometimes CBER research changes the way scientists look at a problem so their research is more efficient. For example, in the field of gene therapy, a strain of the common cold virus called an adenovirus, is used as a vector – delivering therapeutic genes to treat both inherited and non-inherited conditions. However, success of this therapeutic approach has been hampered in part by the finding that an immune response to the adenovirus may prevent efficient delivery of the therapeutic genes to their targets, such as cancer cells. The problem appeared to be that once inside the body, the adenovirus attaches a blood clotting protein called FX to itself and binds to liver cells. As a result the vector doesn’t reach the desired target cells where it would deliver the therapeutic gene.
Some scientists thought that altering the virus so it couldn’t bind FX would let it avoid the liver, making it a more efficient vector. However, scientists in the Office of Cellular, Tissue and Gene Therapies (OCTGT) discovered that adenovirus commandeers the FX protein to use as a shield to evade attack by the immune system. So removing it would likely enable the immune system to attack and disable the adenovirus and block treatment. This new knowledge that the adenovirus needs FX to disguise itself from the immune system will help guide researchers to design gene therapy vectors that survive in the bloodstream and reach their desired target cells.
Another group of scientists, in the Office of Blood Research and Review (OBRR), has contributed to our understanding of why African Americans are significantly more likely than whites to produce antibodies against a drug used to treat hemophilia A. People with hemophilia A carry a mutation in the gene for the protein Factor VIII (FVIII) – a protein that plays an essential role in clotting and preventing blood loss. This mutation either eliminates or greatly reduces the amount of Factor VIII in the blood. Fortunately, there is a therapeutic form of FVIII made through biotechnology that is used to replace faulty or missing, natural FVIII. But unfortunately, some African Americans with hemophilia A make antibodies against therapeutic FVIII. These antibodies attack it and disrupt treatment. The FDA scientists discovered certain genetic variations in the gene for Factor VIII made by these individuals that appear to be responsible for this immune system attack. The discovery is an important step in developing ways to predict which patients will develop antibodies against this complication. And that is an important step toward developing a personalized-medicine approach to hemophilia A by custom-designing medical responses to this life-threatening disease.
The examples I’ve given of CBER research here and in my previous blog are just a small sample of the important knowledge our scientists are creating that supports efforts of medical researchers striving to develop products that improve public health nationally and globally. In 2013, CBER scientists published their research findings in over 200 journals and books.
I’ll be back to update you on more exciting research from CBER during 2014.
Carolyn A. Wilson, Ph.D., is Associate Director for Research at FDA’s Center for Biologics Evaluation and Research.