NIH grant to UNL promises treatment for Hemophilia B

Seventeen years of research have brought scientists to the brink of developing an effective, low-cost treatment for Hemophilia B, a debilitating genetic bleeding disorder. A $9.98 million grant to a team led by a University of Nebraska-Lincoln biomedical engineer offers a glimmer of hope for clinical trials within five years.

UNL's William Velander heads the team that includes scientists from three universities and two private entities. The grant from the National Heart, Lung, and Blood Institute within National Institutes of Health, allows the team to "transition the science to the level of technology" needed for remaining clinical studies in animals and humans, Velander said.

Velander is a professor of chemical engineering at UNL and holds the Donald R. Voelte Jr. and Nancy A. Keegan Endowed Chair in Engineering at UNL. Funds from the Nebraska Tobacco Settlement Biomedical Research Fund were used to support the recruitment of Velander and to support his research program, making this grant possible.

The product is a blood protein known as Factor IX. When genetics conspire to disable this factor, the person suffers from hemophilia, a disorder characterized by uncontrolled or abnormal bleeding often in the joints and sometimes the brain. Therapy for the hemophilia patient involves transfusions of Factor IX. But, the substance is devilishly difficult to isolate from blood plasma because it exists in minute quantities.

While the blood supply is much safer, it can potentially still carry diseases ranging from HIV to hepatitis to West Nile Virus. The annual cost of Factor IX, the common treatment for bleeding events, can be greater than $100,000 per patient with severe hemophilia. Even in the United States, few patients can afford preventative treatment, which is even more expensive. Because 80 percent of patients are in developing countries, most cannot afford any therapy. This results in a painful and shortened lifespan marred by crippling joint disease and other problems.

The UNL project will shepherd the transition from basic science that has already confirmed the abundance and basic quality of the genetically engineered Factor IX, to trialing it in hemophilic dogs. The key to reaching this point, Velander said, was the team's previous work in developing an abundant and safe source of Factor IX protein-from the milk of genetically engineered pigs. Velander recently presented this work to the World Federation of Hemophilia at its October 2004 meeting in Bangkok.

Earlier work, Velander said, focused on producing Factor IX in a laborious but traditional method in stainless steel bioreactors called upon to mimic the natural synthesis that occurs in the liver. That process worked, but has created such tiny amounts of the product that the supply was limited costly. While Factor IX is produced in the body by the liver, scientists sought an alternative tissue that also makes abundant complex proteins and would be easier to harvest, so they turned to the mammary glands of livestock.

While some teams focused on ruminants - sheep, cows and goats - Velander's team looked at pigs, whose biochemistry was known to be close to humans.

Turns out, the pig team got it right. The types of sugar molecules typically attached to milk proteins of ruminants make it inappropriate for blood proteins like Factor IX. Pig milk proteins, however, are closer to the sugar signature found in many human blood proteins.

A gene that turned on the production of Factor IX was introduced into pig chromosomes, creating what Velander called "a self-replicating bioreactor that follows the genetic laws of nature." These genetically engineered pigs produced large quantities of Factor IX in their milk and both the new gene and the Factor IX was harmless to the pigs.

Using this method to make and then harvest Factor IX dramatically decreases the risk of introducing pathogens into Factor IX products, Velander said. And the abundance of the Factor IX enables intravenous and oral treatments. One problem with treatments with Factor IX is that the body can perceive intravenous introduction of the substance as a foreign body, and attack it, he said. This allergic reaction is a particular problem for infants; once it occurs, Factor IX cannot be easily used to treat hemophilia.

But tests in hemophilic animals at the National Institutes for Health in collaboration with scientists Polly Matzinger and Oral Alpan suggest that ingestion of Factor IX seems to circumvent these types of severe allergic reactions, he said. Oral delivery requires more Factor IX than intravenous therapy, but the sheer amount of Factor IX that can be purified from the pigs' milk will potentially enable oral treatment in humans and especially for infants, Velander said.

"The oral therapy would be a Godsend, a true miracle," he said. "If you have an abundance of the protein, you can potentially overcome the inefficiencies of orally delivered therapies."

"The animal testing results with oral delivery have been thus far pretty stunning," he said.

The process could provide treatment costing $2,000 to $10,000 per year, he said. Governments of several countries are interested in the process due to its low cost and efficiency. The idea of a transgenic pig derived product also has been met with a formal endorsement proposed by the National Hemophilia Foundations' Medical and Scientific Advisory Committee.

The transgenic Factor IX pigs are patented by the American Red Cross and the Commonwealth of Virginia. The pigs are housed in Virginia in an isolated facility that protects them from disease. In theory, several hundred pigs could satisfy the Factor IX needs of Hemophilia B patients worldwide.

Hemophilia B affects approximately 15,000 people in the United States. Some 500,000 and 1 million people worldwide have some type of hemophilia. Factor IX is a treatment for Hemophilia Type B, which afflicts about 20 percent of hemophiliacs. Hemophilia Type A is treated by Factor VIII which has the same lack of abundance as Factor IX.

"The developmental lessons learned with Factor IX will lead directly to Factor VIII product," Velander said. "Factor VIII is only three years behind the pace set by Factor IX."

UNL scientists working with Velander on the project include Kevin Van Cott, a professor of Chemical Engineering as well Professors Michael Meagher and Todd Swanson of the Biological Process Development Facility. Paul Monahan and Timothy Nichols of the University of North Carolina at Chapel Hill will lead the hemophilic animal studies. Others sharing in the grant are Stephan Abramson, LifeSci Partners of California; Julian Cooper, ProGenetics LLC, of Virginia; William Dernell and Mark Manning of Colorado State University;

"While a lot of people with complex diseases are frustrated by the apparent slowness of the development of new therapies, it takes a lot of scientists working a long time to understand the required processes," Velander said. "Even though the wait is long, there's hope. There's a glimmer of hope because we really can foresee clinical trials on this."

Contact: William Velander, chemical engineering (402) 472-3697; Monica Norby, Office of Research, (402) 472-3554