WASHINGTON — The Food and Drug Administration announced Tuesday that it has approved the first pill to treat and prevent outbreaks of genital herpes, an incurable, sexually transmitted disease that may afflict as many as 20 million Americans.
The drug is not a cure for herpes, but it can provide effective, long-term relief from symptoms and significantly reduce the chance of spreading the virus, the agency said. It will be available by prescription starting Feb. 11 under the trade name Zovirax and is an oral form of acyclovir, already marketed as an ointment and used intravenously in hospitals.
The pills can "dramatically benefit" both those who experience only occasional outbreaks and want to lessen the symptoms and those who suffer frequent attacks and want to prevent them entirely, according to Dr. Ronald Keeney, a medical adviser at Burroughs Wellcome Co. of Research Triangle Park, N.C., manufacturer of the pills. The drug has been approved for use during periods of up to six months.
"Patients can have a tailor-made therapy for their patterns of disease," Keeney said.
The FDA said genital herpes "has become almost epidemic," with 300,000 new cases reported each year--second only to gonorrhea, which strikes 1 million Americans annually. Gonorrhea, which is caused by bacteria, can be treated and cured with antibiotics.
Genital herpes, a contagious disease spread by sexual contact, usually appears up to three weeks after exposure to the virus with symptoms that include pain, tingling and small blisters. Some victims experience rare outbreaks after the initial episode, while others can suffer a dozen or more recurrences a year.
The FDA said two studies supported by the National Institutes of Health demonstrated that oral acyclovir taken regularly for up to four months reduced the number of recurrences, as well as their severity, in more than 95% of the cases. Subsequent attacks were prevented entirely in 40% to 75% of those patients, the FDA said, and short-term treatment of recurrences was also effective in some patients with less frequent attacks.
But Dr. Stephen Straus, a leading herpes researcher at the National Institute of Allergy and Infectious Diseases--and an author of one of the NIH-sponsored studies--cautioned against long-term use of the drug by anyone other than those who have more than 12 recurrences a year. Straus, who believes additional studies are needed to evaluate the drug's effects over an extended period, supports short-term use of the drug to alleviate symptoms.
"Those who have frequent and severe recurrences will benefit the most, but with most victims--those who have infrequent and mild recurrences--it won't make a major difference," he said.
Cut Contagious Period
Dr. Yvonne J. Bryson, assistant professor of pediatrics at UCLA, said Tuesday at a New York news conference sponsored by the drug's manufacturer that the capsules can cut recovery time in half and reduce the disease's contagious period, generally five to seven days, to two or three days.
And Keeney said studies showed that the drug could reduce first episodes of the disease, which he described as "usually the most severe," from three weeks to one week.
The manufacturer said that the drug works by blocking reproduction of the virus. It does not, however, kill the latent form of the virus. Keeney said the prescribed dosage for preventing outbreaks was three 200-milligram capsules a day, at a cost of about $50 to $60 a month. When used only to alleviate symptoms, the capsules can be taken five times a day for five days, at a cost of about $15 to $18 per treatment period, he said.