By Jose G. Montoya et al.
There is no known treatment for chronic fatigue syndrome (CFS). Little is known about its pathogenesis. Human herpesvirus 6 (HHV-6) and Epstein–Barr virus (EBV) have been proposed as infectious triggers.
Thirty CFS patients with elevated IgG antibody titers against HHV-6 and EBV were randomized 2:1 to receive valganciclovir (VGCV) or placebo for 6 months in a double-blind, placebo-controlled trial. Clinical endpoints aimed at measuring physical and mental fatigue included the Multidimensional Fatigue Inventory (MFI-20) and Fatigue Severity Scale (FSS) scores, self-reported cognitive function, and physician-determined responder status. Biological endpoints included monocyte and neutrophil counts and cytokine levels.
VGCV patients experienced a greater improvement by MFI-20 at 9 months from baseline compared to placebo patients but this difference was not statistically significant. However, statistically significant differences in trajectories between groups were observed in MFI-20 mental fatigue subscore (P=0.039), FSS score (P=0.006), and cognitive function (P=0.025). VGCV patients experienced these improvements within the first 3 months and maintained that benefit over the remaining 9 months. Patients in the VGCV arm were 7.4 times more likely to be classified as responders (P=0.029).
In the VGCV arm, monocyte counts decreased (P < 0.001), neutrophil counts increased (P = 0.037) and cytokines were more likely to evolve towards a Th1-profile (P < 0.001). Viral IgG antibody titers did not differ between arms.
VGCV may have clinical benefit in a subset of CFS patients independent of placebo effect, possibly mediated by immunomodulation and/or antiviral effect. Further investigation with longer treatment duration and a larger sample size is warranted.
Source: J. Med. Virol. 9999:1–9, 2013doi: 10.1002/jmv.23713. Jose G. Montoya, Andreas M. Kogelnik, Munveer Bhangoo, Mitchell R. Lunn, Louis Flamand, Lindsey E. Merrihew, Tessa Watt, Jessica T. Kubo, Jane Paik, Manisha Desai