Schering-Plough has launched Viraferonpeg (peginterferon alfa-2b) injection for the treatment of chronic hepatitis C as monotherapy in case of intolerance or contraindication to ribavirin. The product is a long-acting "pegylated" form of alpha-interferon. The company says that pegylation of the molecule (attachment of a molecule of polyethylene glycol to the interferon molecule) means that the drug is not filtered by the kidneys as rapidly as the "native" molecule which enables higher drug levels in the bloodstream to be achieved than with standard interferon. As the pegylated formulation is cleared from the body more slowly than standard alpha-interferon, Viraferonpeg monotherapy is administered subcutaneously at a dose of 0.5 or 1µg/kg once weekly for at least six months instead of three weekly injections as for standard alpha-interferon. The safety and efficacy of the combination of Viraferonpeg and ribavirin has not yet been documented. The standard combination of interferon alfa-2b with ribavirin remains the optimal treatment for chronic hepatitis C, Schering-Plough says. Viraferonpeg is available as lyophilised powder with injection kit (net price, single use vials 50µg £67.50, 80µg £108, 100µg £135).