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One-day fight against herpes

New regimens can stop cold sore or genital outbreaks sooner. Next: potentially, a vaccine.

August 14, 2006|Shari Roan | Times Staff Writer

The first outbreak was devastating enough. But within weeks came another outbreak. Then another and another.

For Gina Caprio, then 22, the virus that causes genital herpes was nightmarish, "like my life was over."

An antiviral drug managed to keep the virus under control, preventing recurrences, but she had to take it every day, year-round. For years, that costly and inconvenient regimen has been the lesser of two negatives, not just for Caprio but for the millions of Americans with genital or oral herpes.

Now they have a better choice.

The Food and Drug Administration recently approved two new dosing regimens for the herpes drug Famvir that, used properly, can work in a single day to prevent or curtail an outbreak.

The single-day dosing culminates 25 years of advances against the herpes viruses, researchers say. And the best advance may be yet to come. A vaccine that could prevent herpes in women is being studied -- and the results seem promising.

Three decades ago, no one could have anticipated such success against herpes.

"Herpes is a difficult disease to treat. For years people said it was untreatable," says Dr. Spotswood Spruance, an infectious diseases expert at the University of Utah. "There's a big difference between what we had in the past and the simplicity of this new treatment."

An estimated 50% to 80% of all Americans are infected with the herpes simplex virus type 1, which primarily causes cold sores. Most people are infected during childhood through skin-to-skin contact. HSV-1 can also cause genital infections.

Herpes simplex virus type 2 primarily causes genital blisters and is sexually transmitted. About 20% of American adults have HSV-2.

The severity of infections varies widely. Some people have no symptoms and are unaware they are infected. In those who do have obvious outbreaks, symptoms can range from severe and frequent to mild and infrequent.

"It's a minor illness. But it's a nuisance to many people, and it can be painful and distressing to some," Spruance says. "When it occurs every month or so, people describe it as a serious health problem."

Treatment options evolve

Until 1982, when the first antiviral ointment, acyclovir, was introduced, people with herpes simply suffered through their outbreaks. Acyclovir represented a new class of drugs, called nucleosides, that block viral reproduction.

Once they invade the body, herpes viruses take permanent shelter, nestling quietly in nerve cells until something -- illness, stress, sunburn or unknown factors -- causes the virus to awaken and begin to replicate. Though these early hours of virus activity can produce symptoms, such as tingling, the blisters don't form until later, providing a window of opportunity to stop or limit their formation.

A pill form of acyclovir was introduced in 1985. And drugs that are absorbed more effectively and require fewer doses -- Valtrex (valacyclovir) and Famvir (famciclovir) -- followed. An ointment for cold sores, Denavir (penciclovir), is also available.

"This class of drugs, the nucleosides, is now the standard of care," says Dr. Stephen Tyring, a professor of dermatology at the University of Texas Health Sciences Center at Houston and the chief investigator of a study on genital herpes and single-day dosing of Famvir.

Over the years, doctors have also learned that the medications can be taken in higher doses and for shorter amounts of time, such as three days, particularly when started at the first sign of an outbreak. The single-day Famvir regimens are the latest approach to nipping outbreaks quickly and easily, and also provide guidelines about how soon the medication must be started to prevent or curtail the blisters.

For cold sores, the FDA has approved one 1,500-milligram dose (three 500-milligram tablets) that should be taken within one hour of the first sign of symptoms, such as burning, itching and tingling.

For genital herpes, a 1,000-milligram dose taken twice daily for one day should be effective if taken within six hours of the first sign of an outbreak.

"We knew the earlier you take it, the better. But the high dose and short duration also proved effective and that was a pleasant surprise," Tyring says. "This will appeal to patients because it is so convenient compared to the way it was taken in the past."

The cold sore studies show that the single-day dose, if taken within the appropriate time frame by people with healthy immune systems, shortened outbreaks by about two days and reduced the pain and tenderness of the blisters. It did not prevent outbreaks. However, in the genital herpes study, single-day dosing prevented outbreaks in about half of the people and shortened the outbreak by about two days in the other half.

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