ALS-2200 Phase 1 Trial DesignThis double-blind, placebo-controlled, Phase 1 trial was designed to evaluate the safety and tolerability of single ascending doses of ALS-2200 in healthy volunteers and of multiple ascending doses in people with genotype 1 chronic hepatitis C. A secondary objective was to evaluate the effects on viral kinetics of ALS-2200 during seven days of dosing in people with hepatitis C. The first part of the trial enrolled healthy volunteers to evaluate pharmacokinetics of single ascending doses of ALS-2200. The second part of the study enrolled people with hepatitis C to evaluate the antiviral activity of multiple ascending doses of ALS-2200. Of the patients with hepatitis C in the ALS-2200 treatment groups, two were genotype 1a, 29 were genotype 1b and one patient’s genotype 1 subtype was not able to be determined. About ALS-2200 and ALS-2158 Vertex and Alios are also conducting a Phase 1 seven-day viral kinetic study of a second nucleotide analogue, ALS-2158. Data from this study are expected in the next few months. ALS-2200 and ALS-2158 are nucleotide analogues that appear to have a high barrier to drug resistance based on in vitro studies. Both compounds are designed to inhibit the replication of the hepatitis C virus by acting on the NS5B polymerase. Each compound is structurally distinct (adenosine and uridine) and has a different mechanism of action. In vitro studies of both compounds showed antiviral activity across all genotypes, or forms, of the hepatitis C virus, including genotypes more prevalent outside of the United States. Vertex gained worldwide rights to ALS-2200 and ALS-2158 through an exclusive worldwide licensing agreement signed with Alios BioPharma, Inc. in June 2011. The agreement also includes a research program that will focus on the discovery of additional nucleotide analogues that act on hepatitis C polymerase. Vertex has the option to select additional compounds for development emerging from the research program.