Boehringer Ingelheim has linked up with the USA's Presidio Pharmaceuticals to look at combinations of two of its hepatitis C treatments with one of the San Francisco-based company's drugs.

The firms will run a Phase IIa trial to evaluate Presidio’s pan-genotypic HCV NS5A inhibitor, PPI-668 in combination with Boehringer’s HCV protease inhibitor faldaprevir and its non-nucleoside HCV polymerase inhibitor (BI207127), with or without ribavirin. The combo will be an interferon-free, all-oral, direct-acting antiviral and the 12-week study will begin in the second quarter.

Nathaniel Brown, Presidio’s chief medical officer, said that with "the potent, complementary antiviral activities" of PPI-668, faldaprevir and BI207127, "the present study focuses on patients with HCV genotype-1a infection, which has been harder to treat than HCV genotype-1b in many studies". He added that the trial "will assess the potential of this three-drug oral regimen to achieve high rates of sustained viral clearance in hepatitis C patients, with good tolerance".

Earlier this month, Boehringer unveiled encouraging interim results from a Phase III trial which showed that 80% of HCV patients also infected with HIV achieved early treatment success with faldaprevir combined with pegylated interferon and ribavirin. An ongoing Phase III programme is evaluating faldaprevir plus the aforementioned combo in treatment-naive and treatment-experienced genotype-1 HCV patients, while late-stage studies investigating the interferon-free regimen of BI 207127 in combination with faldaprevir and ribavirin "are well underway".

The deal is a boost for Presidio which late last year mutually terminated a merger with BioCryst Pharmaceuticals in a deal that would have valued the former at approximately $101 million. Financial details of the tie-up with Boehringer were not disclosed.