FDA gives nod to West Nile trial therapy

Intron A, normally used to treat hepatitis C, may help West Nile victims.

NEW YORK (CNN) -- The U.S. Food and Drug Administration cleared the way for the first treatment trial for hospitalized patients with the West Nile virus on Tuesday. Doctors will have the option of treating patients with the drug alpha interferon.

The drug, sold by New Jersey-based Schering Plough as Intron A, is FDA approved for the treatment of hepatitis C.

Researchers hope to enroll 40 patients "as soon as possible," says Dr. James Rahal, director of infectious diseases at New York Hospital in Queens.

In the randomized trial half of the patients will be given Intron A and half will not. Patients who receive Intron A will start the treatment within four days of hospitalization and it will be given for two weeks. The two-week treatment is estimated to cost $2,500 per patient.

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All patients age 50 and over, in geographical areas with at least two confirmed cases of West Nile virus, will be eligible for the trial if they are hospitalized with meningitis.

According to Rahal, these patients have a higher rate of progressing from meningitis to West Nile illness. He adds that patients under age 50 usually recover on their own without treatment and are less likely to progress beyond meningitis.

If blood tests confirm that a patient does not have West Nile virus, the Intron A treatment will be stopped immediately.

Patients under age 50 with a confirmed diagnosis of West Nile will also be eligible.

Rahal first thought of trying hepatitis C drugs because hepatitis C is similar in structure to West Nile and both are classified as a falvo virus. He was also doing lab research with another hepatitis C drug, ribavirin, but discontinued because toxic levels of the drug were required to get benefits.

The amount of Intron A being given to West Nile patients is a much lower dose than that given for long-term treatment of hepatitis C and leukemia, which can also be treated with Intron A. In patients treated with Intron A for 6 to 8 weeks, the side effects include depression and anxiety.

Based on lab research, Rahal believes Intron A will suppress the West Nile virus and increase the immune response in sick patients, which will minimize neurological effects. Rahal hopes the drug will also result in fewer respiratory problems and comas.

After lab research appeared promising, Rahal gave Intron A to 15 patients suffering from St. Louis encephalitis in Louisiana in 2001.

Rahal says the side effects seen in this short course of treatment include lowering the white blood cell count and elevations in liver enzymes. But , he said, problems corrected themselves when the Intron A treatment was stopped.

He adds that since West Nile patients are potentially very sick and because Intron A is serious drug, these patients need to be watched very carefully during this trial.

Rahal said he knows of doctors who want to treat West Nile patients with Intron A immediately, but he encouraged such doctors to contact him first.

The National Institute of Allergy and Infectious Diseases is looking for drugs to treat West Nile virus in humans. They are seeing hope in mouse models with three drugs, including alpha interferon and ribavirin -- but a NIAID researcher who asked not to be identified said, "Potentially a treatment from one of the three is a few years away."

She added that the National Institutes of Health is also looking at nine chemicals that could potentially be turned into drugs if they show promise and the National Center for Vaccine Research is exploring the possibility of a vaccine for West Nile.

In the meantime, NIH says mosquito protection is the way to go. "We know it works."