This study was designed to determine safety and efficacy of a 6-month trial of valacyclovir in single-virus Epstein-Barr virus (EBV) persistent infection. Phase I of this study used four specific criteria to define a subset of patients with chronic fatigue syndrome (CFS). In the second phase, myocardial dynamics were measured by MUGA rest/stress radionuclide ventriculographic (RVG) examinations pre- and posttreatment with valacyclovir. In phase I, a trial was performed in 19 consecutive CFS patients with the following diagnostic conditions: patients met criteria for diagnosis of CFS; they had had CFS for less than 1 year. They demonstrated repetitively abnormal oscillating T waves (ischemic or flat) at 24-h Holter monitoring; and they had elevated serum IgM antibody titers to EBV viral capsid antigen and/or total diffuse early antigen as measured by the enzyme-linked immunosorbent assay method. The treatment group comprised 10 CFS patients with no serum antibodies to human cytomegalovirus, but the control group (nine CFS patients) had, additionally, high titers of serum antibodies (IgG) to conformational structural antigens of human cytomegalovirus. Both the parallel treatment and control CFS groups received valacyclovir 1.0-1.5 gm q.6.h. for 6 months. This valacyclovir dose achieved serum acyclovir C(max) of > 7 microm and high antiviral activity versus EBV (IC(50) of 4.4-13.3 m). In phase II, six additional CFS patients met the same four criteria as the 19 CFS patients in phase I. They had, however, been ill for a mean of 55.8 months. Thus, 25 CFS patients comprise this study. The studies were carried out at a single outpatient practice in Birmingham, MI, U.S.A. Before initiating valacyclovir, and after 6 months of treatment, clinical and laboratory observations were made. The CFS Energy Index point score (Table I) was used to record each CFS patient's functional capacity at baseline and after 1, 3 and 6 months of valacyclovir. Energy Index point scores, as well as EBV and human cytomegalovirus serum antibody titers were assessed. In the second phase, left ventricular dynamics were repeated after 6 months of treatment with valacyclovir. We concluded that the 16 CFS patients (included in both phases of this study) with EBV-persistent infection (EBV single-virus subset) are improved after 6 months of continuous pharmacokinetic dosing with valacyclovir. Nine CFS patients with EBV/human cytomegalovirus co-infection did not benefit from 6 months of similar treatment. Valacyclovir is not an effective anti-human cytomegalovirus antiviral drug. Unimproved CFS patients with co-infections EBV and human cytomegalovirus may require combined treatment with valacyclovir and another drug more active against human cytomegalovirus. This preliminary trial, with a small number of patients, may be critical to an appropriately designed larger, double-blind, placebo-controlled trial.
Copyright 2002 Prous Science