Treatments for human herpes virus 8

Recently, researchers have started to look for drugs that inhibit HHV-8, and to test whether these are effective at reducing the number or size of KS lesions. There is also interest in whether these drugs can prevent KS from appearing in the first place.

Drugs used to treat other herpes virus infections, such as ganciclovir (Cymevene), foscarnet (Foscavir), cidofovir (Vistide) and aciclovir (Zovirax) have been tested against HHV-8. In test tube studies, aciclovir has no effects against HHV-8, ganciclovir and foscarnet have only modest effects, and cidofovir has strong effects. Trials of cidofovir as a treatment for KS are now taking place in the United States.

Other evidence that these drugs may be effective against KS has come from studies of people who received foscarnet or ganciclovir as treatment for cytomegalovirus (CMV) retinitis, although findings were mixed. In a study of over 20,000 HIV-positive Americans, people who received foscarnet at any time were 70% less likely to develop KS than people who never received the drug. Receiving ganciclovir did not seem to affect the risk of developing KS. In a French study of over 16,000 people, neither foscarnet nor ganciclovir was linked to a reduced risk of KS. Lastly, in a study of over 3500 people in the United Kingdom, people who received foscarnet or ganciclovir seemed less likely to develop KS.

A pilot study in which people with KS were treated with intravenous foscarnet found that lesions did decrease during treatment. However, retrospective studies involving foscarnet have found conflicting results in terms of its ability to halt or slow the development of KS. Despite some encouraging results, the intravenous anti-CMV drugs have been discounted as treatments for KS due to severe toxicity.

Better-tolerated broad-spectrum anti-viral drugs such as adefovir (Hepsera) and lobucavir have been developed but there is no information yet about effects against HHV-8.