In vivo antiviral effects of pidotimod.

The effect of pretreatment with pidotimod ((R)-3-[(S)- (5-oxo-2-pyrrolidinyl)-carbonyl]-thiazolidine-4-carboxylic acid, PGT/1A, CAS 121808-62-6) was evaluated in mice infected with two challenging doses of three different viruses. Mengovirus, Herpes simplex, influenza virus were used. The mice were treated 15 days before the virus challenge. The antiviral effect of pidotimod was evaluated as difference in survival time versus control groups challenged with viruses but not pretreated with pidotimod. In groups pretreated and challenged with the lower dose of each virus strain a statistically significant increase in survival time was observed. On the basis of the known effects of pidotimod on immune system, this effect is due to an immunostimulating effect of this drug.