Vertex Pharmaceuticals Incorporated,a global biotechnology company that aims to discover, develop and commercialize innovative new medicines, has entered into a non-exclusive agreement with GlaxoSmithKline (GSK) to conduct a phase 2 proof-of-concept study of an all-oral regimen for the treatment of hepatitis C containing Vertex's nucleotide analogue hepatitis C virus (HCV) polymerase inhibitor VX-135 and GSK's NS5A inhibitor GSK2336805.

Vertex and GSK plan to initiate the study in early 2013, pending discussions with regulatory authorities. The study is expected to evaluate safety, tolerability and viral cure rates using a 12-week combination of VX-135 and GSK2336805. The companies will jointly fund costs associated with the study. There are no up-front or milestone payments associated with the agreement.

VX-135 is an investigational uridine nucleotide analogue pro-drug designed to inhibit the replication of the hepatitis C virus by acting on the NS5B polymerase. GSK2336805 is an investigational NS5A replication complex inhibitor being developed by GSK for the treatment of hepatitis C.

"This agreement underscores our broad commitment to develop all-oral treatment regimens for people with hepatitis C using medicines within our own pipeline and by working in collaboration with other companies like GSK who share our commitment to further improve treatment of this disease," said Robert Kauffman,  snior vice president and chief medical officer at Vertex. "We are focused on the development of new all-oral treatments for hepatitis C that have the potential to provide a high cure rate with only 12 weeks of treatment, and we look forward to the start of this study with GSK."

The phase 2 proof-of-concept study is expected to begin in early 2013, pending discussions with regulatory authorities, and will enroll people who have chronic non-cirrhotic genotype 1 hepatitis C and have not previously been treated (treatment-naïve). The study will be conducted in the US by Vertex, and costs associated with the study will be split equally between the two companies. The goals of the study will be to evaluate safety, tolerability and viral cure rates (SVR12; undetectable hepatitis C virus 12 weeks after the end of treatment) of multiple 12-week combination regimens of VX-135 and GSK2336805, with and without ribavirin. Additional information on the phase 2 study will be provided upon initiation of the study. Further clinical development activities beyond the phase 2 proof-of-concept study are not covered as part of this agreement.

VX-135 (ALS-2200) is a uridine nucleotide analogue pro-drug that appears to have a high barrier to drug resistance based on in vitro studies. It is designed to inhibit the replication of the hepatitis C virus by acting on the NS5B polymerase. In vitro studies of the compound showed antiviral activity across all genotypes, or forms, of the hepatitis C virus, including genotypes more prevalent outside of the United States.

Earlier this year, Vertex announced the first 7-day viral kinetic data for VX-135. Based on these data, the company plans to initiate multiple all-oral, phase 2 proof-of-concept studies, including a study of VX-135 and ribavirin and a study of VX-135 and telaprevir, the company's approved protease inhibitor marketed as INCIVEK for people with chronic genotype 1 hepatitis C. Vertex is on track to initiate the study of VX-135 in combination with ribavirin by the end of 2012, followed by the study with telaprevir in early 2013. The studies will evaluate safety, tolerability and viral cure rates (SVR12; undetectable hepatitis C virus 12 weeks after the end of treatment) of 12-week combination regimens in people with chronic non-cirrhotic genotype 1 hepatitis C who have not previously been treated (treatment-naïve).

Vertex gained worldwide rights to VX-135 through an exclusive 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.