New dosing attacks herpes faster By SHARI ROAN
Los Angeles Times
The Food and Drug Administration has approved two new dosing regimens for the herpes drug Famvir that, used properly, can work in a single day to prevent or curtail a herpes 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.
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 percent to 80 percent of 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 percent 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. A pregnant woman with an active infection -- whether symptoms are apparent or not -- can transmit the virus to her baby at birth, causing serious problems such as seizures, blindness, spasticity or death.
Until 1982, when the anti-viral ointment acyclovir was introduced, people with herpes simply suffered through 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 replicate. Although these early hours of virus activity can produce symptoms such as tingling, the blisters don't form until later, providing a window to stop or limit their formation.
A pill form of acyclovir was introduced in 1985. 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 learned that the medications can be taken in higher doses for shorter periods, such as three days, particularly when started at the first sign of an outbreak. The single-day Famvir regimens are the latest approach to warding off outbreaks quickly and easily, and also provide guidelines about how soon 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 or 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.
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.
It's crucial to have the medicine handy and to take it right away for the best chance of stopping an outbreak, says Spruance, the lead investigator of the cold sore study. The tingling, itching or burning sensation is a sign that the virus has become active and is replicating. Most herpes sufferers can identify those symptoms easily, he says.
Doctors say not enough people obtain treatment for herpes. Even those with infrequent outbreaks should inquire about medication, experts say. Herpes can be transmitted during outbreaks and even when someone is asymptomatic. "People with mild or infrequent outbreaks are unlikely to seek medical attention," Tyring says. "But they could still spread it to someone else, or a baby could be born to a mother who has it. That is the worst-case scenario."