Peginterferon alfa-2a (Pegasys) and ribavirin (Copegus) are manufactured by Roche. For genotypes 2 and 3, the licensed regimen is peginterferon alfa-2a 180 micrograms once per week plus ribavirin 800 mg/dayfor 24 weeks. This course of therapy costs £5,019 (excluding VAT; BNF50). For genotypes 1, 4, 5 and 6, the regimen is peginterferon alfa-2a 180 micrograms once per week for 48 weeks plus ribavirin 1,000 mg/day (for people weighing less than 75 kg) or 1,200 mg/day (for those weighing 75 kg or more) for the same length of time as peginterferon alfa. The cost is £10,963 or £11,889 for 48 weeks depending on body weight. For peginterferon monotherapy, the cost of treatment is £6,339 (for 12 months) for all genotypes.