A study finds a new class of anti-viral drug is safe and effective for treating outbreaks related to recurrent genital herpes.

Treatment for genital herpes currently involves taking drugs known as nucleoside analogues (such as valacyclovir) that work by inserting themselves into the viral DNA and disrupting the chain of viral replication.

Another class of drugs (not currently on the U.S. market) called helicase-primer inhibitors (HPI) also work by stopping HSV replication, but break up the chain in a different way. HPI target an enzyme called helicase-primase that facilitates HSV replication untwisting the DNA double helix of the virus. By acting on the enzyme, HPI keep the DNA strands intact. How well does it actually work?

To assess how well a novel HPI, ASP2151, works in healing lesions related to recurrent genital HSV, researchers randomized 427 subjects to receive either placebo or one of five treatment regimens: 100, 200, or 400 mg of ASP2151 daily for three days; a single 1200 mg dose of ASP2151, or 500 mg of valacyclovir twice daily for three days. Effectiveness was assessed by the amount of time (measured in hours) lesions took to heal (excluding aborted lesions).

Median healing time for lesions with the valacyclovir group was 114 hours. Healing time with the ASP regimens was similar: 102.1 hours with the 1200 mg group; 106.2 with 200 mg; and 115.9 with 400 mg. Median healing time for those receiving placebo was 139.8 hours.

In addition to showing promise in speeding healing time, the investigators say ASP2151 appears to be a safe option for treating recurrent genital HSV. However, at this time the company s not pursuing further development of this compound.

Reference
Tyring S, Wald A, Zadeikis N, Dhadda S, Takenouchi K, Rorig R. ASP2151 for the treatment of genital herpes: a randomized, double-blind, placebo- and valacyclovir-controlled, dose-finding study. J Infect Dis, 2012. 205(7):1100-10.