Safety, pharmacokinetics, and antiviral activity of the cyclophilin inhibitor NIM811 alone or in combination with pegylated interferon in HCV-infected patients receiving 14 days of therapy

BackgroundCyclophilin inhibitors have shown activity against a variety of viruses, including HCV. NIM811, a novel, non-immunosuppressive cyclophilin inhibitor was studied in ascending doses in a randomized, double-blind, placebo-controlled 14-day trial in genotype 1 HCV patients. Doses of 10 up to 600 mg were given orally once or twice daily as monotherapy (9:3 randomization of NIM811:placebo). 600 mg or placebo bid for 14 days was then co-administered with pegylated interferon alpha (PEG-IFN-α) administered on days 1 and 8 to genotype 1 relapsers.ResultsNIM811 was well tolerated at all doses. Although lack of antiviral effect was noted in the monotherapy arms, liver transaminase normalization occurred at doses over 75 mg. Mild, clinically non-significant elevations of bilirubin, and significant declines in platelet numbers were observed in the 400 and 600 mg bid groups. In the combination group, the mean HCV RNA decline was 2.85 log, compared to a 0.56 log in the PEG-IFN alone arm. The mean ALT (alanine transaminase) declined significantly by day 14 in the combination, but was unchanged in the PEG-IFN alone group. In the combination therapy group, the mean platelets were 203 × 109/L at baseline and fell to 105 × 109/L by day 14; for patients treated with PEG-IFN the values were 177 × 109/L and 139 × 109/L. There was a significant increase in bilirubin, although this did not reach clinically concerning levels. There were no severe or serious adverse events. The pharmacokinetics in both monotherapy and combination arms were dose linear and not affected by PEG-INF.ConclusionNIM811 monotherapy resulted in a normalization of liver transaminases in the absence of significant virological response. The combination of NIM811 and pegylated interferon alpha showed significant antiviral activity compared to interferon alone in genotype 1 HCV relapsers. The use of oral cyclophilin inhibitors as part of a combination regime for treatment of hepatitis C, especially to deter resistance, holds promise.