[Prospects and current data in antiviral chemotherapy].

The advances achieved in our knowledge on the virus multiplication cycle and the challenge created by the advent of AIDS have resulted in a rational development of new antiviral agents. However, antiviral chemotherapy is hindered by several obstacles: (1) most antiviral drugs are cytotoxic, with the exception of acyclovir which owes its remarkable safety to its activation by the thymidine kinase of the herpes simplex viruses and of the varicella-zoster virus; (2) the risk of selecting resistant strains by mutation of viral enzymes is the unavoidable price to pay for the specificity of new antiviral agents which interfere with these enzymes; so far, this risk seems to apply only to immunocompromised patients; (3) latent viral infection, defined as the lack of active multiplication of the virus, cannot be eradicated by the antiviral drugs available at present since these drugs are inhibitors of viral multiplication. However, anti-sens oligonucleotides could, at least in theory, be used to treat this type of infection which is not limited to the Retroviridae or Herpesviridae families. Finally, antiviral drugs active against life-threatening infections that are as common as rabies and the severe forms of measles or viral hepatitis remain to be discovered.