No therapy is currently FDA approved specifically for HHV-6.

Standard treatment for HHV-6 encephalitis is intravenous ganciclovir (Cytovene) or foscarnet (Foscavir) although both of these drugs are approved only for HHV-5 or cytomegalovirus (CMV) retinitis. Ganciclovir is also available in an oral form (Valcyte ). In vitro studies have shown that cidofovir (Vistide), which is also approved for CMV retinitis, is more effective than either ganciclovir or foscarnet (DeClercq 2003, Long 2003). However it is not known how well cidofovir crosses the blood brain barrier.

Valcyte was introduced in 2001 and is now used in the US to treat AIDS retinitis and to prevent

herpesvirus reactivations in transplant patients. Stanford University infectious disease specialist Jose Montoya is undertaking a placebo controlled trial of Valcyte in Chronic Fatigue Syndrome patients who have central nervous system abnormalities and elevated antibodies to HHV-6 and EBV. Montoya is convinced that elevated antibodies to HHV-6 can be a sign of chronic reactivation. In a pilot study, he found that patients treated with Valcyte did show a drop in antibody titers after six months, suggesting that there was indeed an active infection, presumably in the brain tissues. None of those patients tested positive for the actual virus; elevated antibodies were the only clue (Kogelnik 2006).

Valcyte can be associated with bone marrow

suppression in rare circumstances and both cidofovir and foscarnet carry risks of kidney toxicity. The HHV-6 Foundation funds efforts to find safer and more effective antivirals. For example, they funded two research groups to look at epilepsy drugs to see if any of them were active against HHV-6B. Of interest, both Lamotrigine (Lamictal) and Valproic acid (Depakene) showed in vitro antiviral activity against HHV-6B but not against HHV-6A.

There is an urgent need for a clinical trial to determine if HHV-6B specific antiviral therapy would be an effective treatment in a subset of patients with mesial temporal lobe epilepsy.