Valomaciclovir may be effective in treating infectious mononucleosis

Patients with acute infectious mononucleosis due to primary Epstein-Barr virus who were treated with valomaciclovir were four times as likely to have a significant decrease in viral load than patients who were administered placebo, according to findings presented at the 49th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

The findings were presented by Henry Balfour, MD, of the University of Minnesota.

The study involved 21 patients older than 15 who had acute infectious mononucleosis due to Epstein-Barr virus infection. According to pre-determined criteria, patients were enrolled an average of six days after onset of illness. They were randomly assigned valomaciclovir at 4 g/day or placebo and followed for six months. Researchers observed clinical, virologic, immunologic and pharmacologic responses.

“This was a highly intensive study,” Balfour said. “We had strict criteria for enrollment, and we gathered a great deal of information in terms of clinical, virologic and immunologic response. If there is a benefit to taking this drug, we really wanted to demonstrate it.”

There were 11 patients in the valomaciclovir group and 10 patients in the placebo group. Patients in the treatment group had significantly faster clinical improvement than those in the placebo group, according to physical exam and symptom scores from each visit (P<.05).

Patients in the valomaciclovir arm improved with regard to severity of illness and SF12 scores, but not at a rate that was statistically significant.

Significant decreases in the oral compartment were observed in the treatment group compared with the placebo group (oral cell pellet, P=0.02; oral supernatant, P=0.002, unpaired t test, 2-sided).

The proportion of subjects who had at least a 2 log₁₀ decrease in Epstein-Barr viral load in the oral compartment was also significantly greater in the treatment group than in the placebo group (treatment: 8/11; placebo: 1/10; P=0.008).

“We saw good adherence rates with valomaciclovir,” Balfour said. “Beyond that, we demonstrated an in vivo effect of the drug on Epstein-Barr virus for the first time. In short, patients got better faster.”

Balfour H. #V-1256a. Presented at: the 49th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy; San Francisco; Sept. 11-15, 2009.