The results signify a potentially effective therapy for treating HCV - a serious disease that causes inflammation of the liver. According to the Centres for Disease Control and Prevention and the World Health Organisation, HCV affects as many as 2.7 million people in the US and as many as 185 million people worldwide.
The goal of HCV therapy is clearance of the virus from the patient at six months post-treatment, which is termed a sustained viral response (SVR). However, current treatments provide a sustained viral response for approximately 50 per cent of patients chronically infected with genotype 1 HCV.
VX-950 directly targets the enzyme HCV protease, an essential enzyme in hepatitis C virus replication. The study enrolled 34 patients with chronic genotype 1 HCV infection who were treated for 14 days with placebo or one of three dose regimens of VX-950. Patients receiving 750 mg of VX-950 every eight hours achieved a median reduction in HCV-RNA of greater than 4 log10, equivalent to a more than 10,000-fold decrease in viral levels, at the end of 14 days of treatment. A median reduction in HCV-RNA of greater than 2 log10 was seen in each of the other two VX-950 dose groups at the end of 14 days of treatment. Every patient receiving VX-950 achieved greater than a 2 log10 reduction in HCV-RNA within the first three days of treatment.
Genotype 1 HCV infection is the most difficult strain of HCV to treat and the most prevalent strain in the United States, Western Europe and Japan.
"Vertex is committed to developing innovative compounds for the treatment of chronic HCV infection. VX-950, one in a promising new class of direct antivirals, underscores that commitment," said Joshua Boger, chairman and chief executive officer of Vertex.
Based on the results of the Phase Ib clinical study, the Company plans to explore the development of VX-950 as monotherapy and in combination with other HCV treatments.
Vertex expects to file an investigational new drug (IND) application in the second half of 2005 to support Phase II clinical development of VX-950 in the US. In collaboration with Vertex, Mitsubishi Pharma Corporation is developing VX-950 in Japan and certain Far East countries.
HCV often goes undetected for up to 20 years following initial infection, and can progress to fibrosis, cirrhosis, liver cancer and, ultimately, liver failure. Each year, 8000 to 10,000 people in the US die from complications from HCV.
According to the National Foundation for Infectious Diseases, complications from HCV are now the leading reason for liver transplants in the US, accounting for nearly 2,000 liver transplants annually.
The HCV treatment landscape has three key defining characteristics that illustrate the present and future market opportunity in this area that is currently estimated to be $2.3 billion in worldwide sales in 2004.
A vast majority of the infected individuals remains undiagnosed. In the US it is estimated that up to 70 per cent of the HCV-positive individuals have not been identified.
Many patients fail current treatment regimens of suffer from a relapse. In addition, currently available therapies are poorly tolerated and cause severe side effects, making it difficult to treat many patients.
The number of individuals who have been infected for more than 20 years is increasing. The peak incidence of infection occurred in the mid-1980's. s complications form HCV take 20 to 30 years to develop, the number of people requiring treatment is predicted to dramatically increase. Hospitalisation and death rates are projected to triple over the next 10 to 15 years, mostly affecting people who are currently unaware of their status.
The overriding problem facing patients who are non-responsive to pegylated interferon (peg-IFN) and ribavirin (the current standard of care) is lack of an alternative antiviral treatment options, and only a very low percentage will achieve a sustained viral response upon re-treatment with peg-IFN and ribavirin
Hoffmann-La Roche announced on December 3, 2002 that the US Food and Drug Administration (FDA) had approved combination therapy with Pegasys (peginterferon alfa-2a) and Copegus (ribavirin) for the treatment of adults with chronic hepatitis C.
Pegasys and Copegus, posted combined worldwide sales of €512.3 million (€400 million) in the first half of 2004. Less than one and a half years after its first launch Pegasys has now achieved significant global market share. The drug has been the subject of rapid uptake in major markets, including the US.
Schering-Plough's Peg-Intron hepatitis C treatment had been on the market for nearly four years now with 2004 sales of $563 million (€439.8 million).