Shares in US biotech InterMune rocketed this week on the success of a mid-stage trial of its hepatitis C candidate danoprevir, which is being developed with partner Swiss pharmaceutical giant Roche.

Danoprevir is being assessed in treatment-naïve patients with hepatitis C in combination with Roche’s Pegasys (peginterferon alfa-2a) and Copegus (ribavirin), but its development hit a rocky patch in November last year after the firm said it would stop testing the highest dose - 900mg - because of elevated levels of ALT, an enzyme associated with liver problems.

So news that an interim analysis of results found that both the 300mg and 600mg doses of the drug in combination with Pegasys and Copegus induced a better virologic response in patients than a mix of Pegasys/Copegus/placebo - 88%, 89% and 43%, respectively - will be very welcome indeed.

Small elevations of ALT were still recorded in some patients, but future development of danoprevir “is expected to be conducted in combination with ritonavir at total daily doses that are 10%-25% of those examined in this study”, noted Frank Duff, head of Roche’s Clinical Development for Virology.

Best results
He said the pharmacokinetics/pharmacodynamics and safety data from this large, well-controlled study coupled with other data being collected “will be very helpful” in choosing the optimal dose and regimen for the ritonavir-boosted danoprevir development program.

Dan Welch, chairman, chief executive and president of InterMune, said the results of the study “are among the very best reported by any direct-acting antiviral compound to date, reinforcing our view that danoprevir may potentially play a meaningful role in the treatment of HCV patients”, with “attractive advantages of dosing convenience and increased safety margin”.