VS411

VS411 is a first-in-class antiviral hyper-activation-limiting therapeutic (AV-HALT) developed by ViroStatics for the treatment of HIV/AIDS. It is a fixed-dose combination of the nucleoside reverse transcriptase inhibitor (NRTI) didanosine (400 mg) and the cytostatic agent hydroxyurea (600 mg). Formulated as a single-dosage oral capsule, the drug is designed to provide a slow release of didanosine to minimize toxicity while maintaining antiviral efficacy. VS411 exerts a dual mechanism of action: didanosine inhibits HIV-1 reverse transcriptase to block viral replication, while hydroxyurea acts as a ribonucleotide reductase inhibitor to deplete intracellular deoxynucleotide pools and dampen the chronic immune system activation characteristic of HIV infection. Clinical development reached Phase 2a, showing reductions in viral RNA and immune activation markers, but the program is no longer being pursued for commercial development.

Other names

didanosine + hydroxyurea