Isis' CMV Antisense Effective And Safe

Isis Pharmaceuticals has presented new data which support the effectiveness of its antisense oligonucleotide for cytomegalovirus retinitis, fomivirsen (ISIS 2922), and suggest that the drug may have some advantages over current treatments for the condition. The new data were presented at the International Consensus Symposium on Advances in the Diagnosis, Treatment and Prophylaxis of CMV Infection, which was held in Florida, USA last week.

Daniel Kisner, Isis' president and chief operating officer, said that intravitreal fomivirsen produced rapid and prolonged diseases remission at a dose of 300mcg in CMV retinitis patients who had failed on other drug treatments, and at a dose of 150mcg in patients with early-stage disease. This prolonged disease remission was seen in patients who received fomivirsen monotherapy, as well as those who received it in combination with the antiviral ganciclovir.

The oligo was well-tolerated by patients and was associated with no systemic toxicities, continued Dr Kisner. Furthermore, the incidence of peripheral vision changes, which can be indicative of retinal detachment and had been seen with the 300mcg dose, was not observed with the lower 150mcg dose. A current analysis of 107 patients who received the higher dose of fomivirsen suggests that the incidence of these peripheral vision changes was low (6.7%), and that these changes were reversible, at least in some patients. The product appears to be associated with a much lower rate of retinal detachment than is encountered with Vitrasert, Chiron's intravitreal ganciclovir implant, noted Dr Kisner.