[Note: As described in a Los Angeles Times article, “Antiviral drug found to reduce severity of mono,” viral load was reduced in treated youngsters, who averaged a 50% symptom improvement in 7.6 days vs. 11.1 days for placebo. The next challenge: identify factors that may justify treatment – e.g., characteristics that appear linked to more severe illness, or to later development of illnesses such as ME/CFS.]
Background: Infectious mononucleosis (IM) causes substantial loss of productivity in teenagers and young adults. We conducted an investigator-initiated clinical trial of the guanosine nucleoside prodrug Valomaciclovir (VALM) for infectious mononucleosis under an investigator IND.
Methods: Subjects over the age of 15 with acute infectious mononucleosis were randomized to 21 days of VALM 4 g/day or placebo (PBO) and followed for 6 mo. Clinical, virologic, immunologic and pharmacologic observations were made during 10 visits.
21 subjects ages 16 to 24 yr (median age, 19.6 yr) enrolled a median of 6 days after onset of infectious mononucleosis confirmed due to primary Epstein-Barr virus (EBV) infection. 11 were assigned to VALM and 10 to PBO.
• VALM subjects had significantly faster clinical improvement than PBO recipients as documented by comparing the slopes of the plots of their physical exam/symptom scores from each visit during the treatment period (95% confidence intervals did not overlap; P<0.05).
• Severity of illness and SF12 scores improved faster in VALM subjects but rates were not statistically significant.
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• VALM produced a significant decrease in median EBV load in the oral compartment vs PBO (oral cell pellet, P=0.03; oral supernatant, P=0.001, unpaired t test, 2-sided).
• The proportion of subjects who had at least a 2 log10 decrease in EBV load in the oral compartment was also significantly different (VALM 8/11; PBO 2/10; P=0.03, Fisher exact test, 2-sided).
• No differences were found in clearance of EBV DNAemia, CD8:CD4 ratios, CD8 lymphocytosis, or CD8 responses to lytic and latent EBV tetramers in the VALM vs PBO subjects.
• 9 of 11 VALM subjects had at least 1 plasma concentration of H2G, the parent compound of VALM, above the in vitro IC50 for EBV in subject-derived lymphoblastoid cells, which is 2.1 micromolar.
This is the first demonstration of a clinical benefit and an in vivo antiviral effect of VALM in acute infectious mononucleosis due to primary EBV infection.
This study encourages additional investigation of the role of VALM in the management of diseases associated with EBV.
[ClinicalTrials.gov Trial: NCT00575185]
Source: Interscience Conference on Antimicrobial Agents & Chemotherapy, Sep 14, 2009, San Francisco. Presentation Number V-1256a; Session 146 – Herpes Viruses and Other Viral Infections in Immunocompromised Hosts. By Balfour HH, Vezina HE, Hogquist KA, Brundage RC, Anderson BJ, Odumade OA. University of Minnesota, Minneapolis, USA.