Background and design: This multicenter trial (19 sites) was initiated in 1984 in more than 1100 immunocompetent individuals with a history of frequently recurring genital herpes (mean, > or = 12 episodes per year). The first year of this suppressive therapy trial was placebo controlled, with acyclovir being provided for episodic treatment in both groups. Thereafter, patients were treated with open-label acyclovir suppressive therapy on a long-term basis (400 mg twice daily) to continue to assess its long-term safety and efficacy. Complete data are available on 389 of the 430 patients who began the fifth year of the study.
Results: Patients were seen quarterly for review of diaries and clinical laboratory evaluations. The percentage of patients recurrence free for any 3-month quarter of the fifth year ranged from 86% to 90%. The mean annual number of recurrences per patient declined from 1.7 during the first year to 0.8 during the fifth year of suppressive therapy. The frequency of false prodromes has also decreased over time. More than 20% of the patients receiving suppressive therapy for 5 years have been recurrence free the entire time. The duration of herpetic outbreaks during suppressive therapy has not changed.
Conclusion: This study extends the safety and efficacy profile of oral acyclovir in the suppression of genital herpes to 5 years. The majority of the patients were recurrence free on an annual basis during suppressive therapy. Therapy was well tolerated. Acyclovir usage was not associated with serious side effects or cumulative toxicity.