Gilead Sciences will submit its new hepatitis C drug sofosbuvir for regulatory approvals in the second quarter after presenting positive data from its fourth and final Phase III study.

The company announced topline results from the Phase III FUSION study evaluating 12- and 16-week courses of therapy with sofosbuvir plus ribavirin in treatment-experienced patients with genotype 2 or 3 chronic HCV infection who failed prior treatment. 50% of patients in the 12-week arm and 73% on 16 weeks of therapy showed no detectable virus; the primary endpoint had been for the virus to be undetectable in over 25% of patients.

Chief scientific officer Norbert Bischofberger said  the study demonstrates that all-oral therapy with sofosbuvir provides significant efficacy among difficult-to-treat HCV patients "who could not be cured by prior regimens containing pegylated interferon and now have limited treatment options". He added that with positive results from all four Phase III trials now in hand, "Gilead is on track to meet its goal of filing regulatory applications in the USA and Europe in the second quarter".

Analysts are impressed by the speed with which Gilead has got sofosbuvir to the filing stage, having acquired the once-daily nucleotide through its $11 billion purchase of Pharmasset just over a year ago. Eyebrows were raised at the size of the price paid for the latter but if sofosbuvir becomes the first interferon-free HCV treatment to be approved, Gilead will be in a very lucrative spot.

Settles with Teva over Viread patent

Meantime, Gilead has agreed to settle a lawsuit with Teva Pharmaceutical Industries relating to patents protecting the former's HIV and chronic hepatitis B drug Viread (tenofovir).

Under the terms of the agreement, the financials for which were not disclosed, Teva will be allowed to launch a generic version of Viread on December 15, 2017. Gilead president John Milligan said "we believe strongly in the validity of our intellectual property", but a settlement "removes some uncertainty and minimises further distraction and investment of human and financial resources associated with this litigation".

The trial concerning the Viread patent, which was scheduled to begin today (February 20) has been adjourned pending completion of activities necessary to finalise the settlement.