NIAID Expands Clinical Trial of Experimental West Nile Virus Treatment

The National Institute of Allergy and Infectious Diseases has expanded its clinical trial of an experimental West Nile virus (WNV) treatment to about 60 sites throughout the United States and Canada. The multi-center trial, which opened at 36 sites last September, is expected to add about 24 new sites this summer, pending internal approval at each institution. A listing of all sites is available at http://www.casg.uab.edu/adult/act%20210WNV.htm.

The study is testing the safety and preliminary effectiveness of using a product containing WNV infection-fighting proteins to treat people whose infection has reached or threatens to reach the brain.

"As West Nile virus disease continues to spread across our country, it is critical that we develop specific treatments for its most severe symptoms," says Anthony S. Fauci, MD, NIAID director. "At present, clinicians have few options besides supportive care for treating people with WNV illness. By expanding this study, we hope to accelerate NIAID's efforts to understand, develop treatments for and eventually prevent this disease."

Until recently, human infection with West Nile virus, which is spread by mosquitoes, was limited to Africa, Asia and the Middle East. Since its arrival in the New York City area in 1999, human WNV infection has increased in scope and severity in the United States each year. In 2003, the U.S. Centers for Disease Control and Prevention (CDC) reported more than 9,860 cases of WNV disease, which included 264 deaths. Thus far in 2004, 78 cases of WNV, including one death, have been reported in eight states.

The main goal of this study, notes Walla Dempsey, PhD, who oversees NIAID's WNV clinical trial contracts, is to assess the safety of a blood plasma-derived substance containing WNV antibodies when given intravenously to patients with WNV infection. Secondarily, she adds, the study seeks preliminary data about the treatment's effectiveness against encephalitis, a brain inflammation caused by WNV infection.

"Information from this study will enable us to better characterize the clinical course of West Nile virus infection," Dempsey says, "which in turn will allow us to design more meaningful clinical trials in the future."

The Israeli company Omrix is providing its product, Omr-IgG-am, for use in the trial. West Nile virus has circulated in Israel for decades, and many Israeli blood donors have antibodies to the virus. The company's product is based on WNV antibodies derived from Israeli donors who have high levels of these antibodies.

The trial can enroll up to 110 patients 18 years old and older who have WNV-related encephalitis or are who at risk of developing this severe neurological complication. Participants will receive a single dose of Omr-IgG-am or a dose of one of two placebos.

Participants are being recruited through NIAID's Collaborative Antiviral Study Group (CASG), headed by Richard Whitley, MD, of the University of Alabama at Birmingham. Information about the trial is located both at CASG's Web site (www.casg.uab.edu) and at clinicaltrials.gov (http://www.clinicaltrials.gov/show/NCT00068055).

Source: National Institutes of Health