The relative merits and drawbacks of new nucleoside analogues with clinical potential.

A large number of nucleoside analogues have been found to have antiviral activity, mainly against herpesviruses. The involvement of cellular as well as viral enzymes in the mode of action of several nucleoside analogues makes a prediction of clinical efficacy difficult. The possibility and consequences of incorporation into cellular DNA are other important aspects of nucleoside analogues as antiviral drugs. It seems likely that in the next few years enough knowledge about mechanism of action, consequences of incorporation into DNA, efficacy in different test systems and in clinical trials will accumulate to allow an understanding of how to design even better antiviral drugs.