Late valacyclovir for herpes yields greater response

By Martha Kerr

NEW YORK (Reuters Health) - Therapy with valacyclovir (Valtrex, GlaxoSmithKline), started within three months of infection with either herpes simplex virus type 1 (HSV-1) or HSV type 2 (HSV-2), reduces the rate of symptomatic outbreaks compared with placebo, Seattle investigators report in the Journal of Sexually Transmitted Diseases.

However, the response rate to valacyclovir in this study was somewhat lower than rates seen in other studies, in which treatment wasn't started for a year or more after the onset of infection, according to Dr. H. Hunter Handsfield of the Batelle Center for Research and Evaluation and the University of Washington's Center for AIDS and STDs and colleagues.

"All the studies to this point were in patients who had been infected for at least a year before treatment," Handsfield told Reuters Health. "That's what FDA approval of valacyclovir is based on."

Handsfield and colleagues conducted a pilot study of 119 patients with early HSV infection who were randomly assigned to valacyclovir or placebo daily for six months.

The average patient age was 28.7 years, 66 percent were women, 63 percent had HSV-1 infection and 18 percent had HSV-2 infection. The maximum duration of infection was three months for eligibility in the trial.

At follow-up, the investigators found that the valacyclovir-treated patients had an average of 1.7 outbreaks of HSV infection per year compared with 3.4 episodes per years with placebo.

The average time to first recurrence of symptoms was 80 days with valacyclovir and 54 days with placebo. Eighteen patients (47 percent) on valacyclovir were recurrence-free at the end of the study period compared with 10 patients (27 percent) on placebo.

Handsfield said that although the response rate is somewhat lower with early compared with delayed antiviral treatment, "there is every reason to suppose, based on the pattern of response seen in other studies, that the response rate will continue to improve over time...and reach that seen in previous studies."

"One important public health message here is that HSV infection...doubles the risk of HIV infection...Patients should be offered early therapy and also counseled about the risk of transmission to uninfected sexual partners," and the importance of abstaining from intercourse during outbreaks and always using condoms.

SOURCE: Journal of Sexually Transmitted Diseases, June 2007.