Fomivirsen Sodium was launched as Vitravene in the US and is
indicated for the local treatment of cytomegalovirus (CMV)-induced retinitis in
AIDS patients. It consists of a phosphorothioate oligonucleotide (PS) comprised
of a sequence of 21 nucleotides. Fomivirsen is synthesized using solid-phase
phosphoramidite chemistry. Fomivirsen inhibits human CMV replication by a
antisense mechanism : it targets an immediate early mRNA of cytomegalovirus,
inhibiting the expression of two regulatory proteins. Fomivirsen was the most
advanced first-generation PS drug candidate in human clinical trials and was the
first agent based on antisense technology to reach the market. In normal human
dermal fibroblast cells, Fomivirsen inhibited AD169 human CMV replication by
more than 90%, at a concentration of 5μM ; it showed greater hCMV replication
inhibitor properties than ganciclovir in several experimental models.
