Vertex Pharmaceuticals Incorporated announced new data from a viral kinetic study of the uridine nucleotide analogue ALS-2200 (VX-135) in development for the treatment of hepatitis C. There was a median 4.08 log10 reduction in hepatitis C virus (HCV) RNA after seven days of dosing with 200 mg once daily in treatment-naïve people with genotype 1 chronic HCV infection and compensated cirrhosis. Among treatment-naïve people with genotypes 3 or 4 chronic HCV infection, there was a median 4.65 log10 reduction in HCV RNA after seven days of dosing with 200 mg once daily.

Prior to a protocol amendment, one treatment-naïve person with genotype 2 HCV infection received 100 mg of ALS-2200 once daily for seven days, and had a 5.04 log10 reduction in HCV RNA after seven days of dosing. ALS-2200 was well-tolerated in this study, there were no serious adverse events and no patients discontinued due to adverse events. These new data are consistent with previously reported data in people with genotype 1 chronic HCV infection, and will be presented the 48th Annual Meeting of the European Association for the Study of the Liver (EASL) in Amsterdam, Netherlands, April 24 to 28, 2013.

These data support Vertex's recently announced non-exclusive agreement with Bristol-Myers Squibb Company to conduct phase 2 studies of once-daily all-oral treatment regimens containing VX-135 and Bristol-Myers Squibb's NS5A replication complex inhibitor daclatasvir for the treatment of hepatitis C. As part of the agreement, Vertex plans to conduct two Phase 2 studies of the combination, including an initial study in treatment-naïve people with genotype 1 HCV infection planned for the second quarter of 2013. Vertex plans to begin a subsequent study in treatment-naïve people infected with genotype 1, 2 or 3 HCV, including those with cirrhosis, in the second half of 2013, pending data from the initial study.

"The viral kinetic data announced to date show the potential for VX-135 to be the backbone of all-oral treatment regimens," said Robert Kauffman, senior vice president and chief medical officer at Vertex. "The data suggest that VX-135 holds promise as a treatment option for people with genotypes 1 through 4 HCV infection, and for people with cirrhosis, who urgently need more effective and better tolerated treatments."

Vertex has multiple ongoing and planned studies of VX-135 as part of all-oral treatment regimens, including a study in combination with ribavirin and studies with other direct-acting antivirals. Vertex plans to begin pivotal development of VX-135 as part of all-oral treatment regimens in 2014, pending data from these studies. The first Phase 2 data for VX-135 as part of an all-oral regimen are expected in the second half of 2013.

VX-135 is a uridine nucleotide analogue pro-drug designed to inhibit the replication of the hepatitis C virus by acting on the NS5B polymerase. ALS-2200 has shown pangenotypic activity in vitro. Vertex gained worldwide rights to ALS-2200 through an exclusive licensing agreement signed with Alios BioPharma, Inc. in June 2011. The agreement also includes a research program that focuses on the discovery of additional nucleotide analogues that act on the hepatitis C polymerase. Vertex has the option to select additional compounds for development emerging from the research programme.