Vertex Acquires VCH-222 and VCH-759, Two Experimental Oral HCV Polymerase Inhibitors

Vertex Pharmaceuticals Strengthens HCV Drug Development Portfolio, Adds Novel Polymerase Inhibitors to Shape New Combinations with Telaprevir

Vertex to acquire privately-held ViroChem Pharma in cash and stock transaction -- Two HCV polymerase inhibitors, VCH-222 and VCH-759, have demonstrated significant antiviral activity in early clinical trials -- First STAT-C combination trial with telaprevir planned for 2H 2009 start.

Cambridge, Mass. & Laval, Quebec -- March 3, 2009 -- Vertex Pharmaceuticals Incorporated (Nasdaq: VRTX), which is developing the hepatitis C virus (HCV) protease inhibitor telaprevir, will add two polymerase inhibitors to its HCV drug development portfolio through a definitive agreement to acquire privately-held ViroChem Pharma Inc. in a stock and cash transaction. With the addition of these compounds, Vertex will advance its strategy to pursue novel combinations of Specifically Targeted Antiviral Therapies for hepatitis C (STAT-Cs) for the treatment of HCV infection.

Following completion of the transaction, Vertex will own worldwide rights to ViroChem's HCV drug development portfolio, including VCH-222 and VCH-759, which have demonstrated substantial reductions in plasma HCV RNA when dosed as single agents and have been well-tolerated in clinical studies to date. In particular, VCH-222 dosed as 750 mg twice daily resulted in a median 3.7 log10 decrease in HCV RNA at the end of dosing in a three-day viral kinetic study, representing the most substantial reduction in viral load reported to date with an investigational HCV polymerase inhibitor dosed as a single agent. Vertex expects to begin clinical evaluation of novel combination regimens of its HCV protease inhibitor telaprevir, currently in Phase 3 clinical development, in the second half of 2009. The transaction is subject to customary pre-closing conditions.

"This acquisition significantly strengthens our pipeline in hepatitis C by bringing together Vertex's telaprevir, our HCV protease inhibitor in registration studies, with the HCV non-nucleoside polymerase inhibitors being developed by ViroChem," said Joshua Boger, PhD, Chief Executive Officer of Vertex. "Through this acquisition, we're well positioned as a leader in the development of HCV therapies. Our goal is to further advance HCV care for patients through the creation of novel and highly potent STAT-C combination regimens."

"This move expands Vertex's global presence in HCV and has the potential to enhance the profile and lifecycle of our telaprevir-based combination regimens. We believe it strengthens our ability to compete and stay at the forefront in developing novel STAT-C combination regimens," added Kurt C. Graves, Executive Vice President, Chief Commercial Officer and Head, Strategic Development at Vertex. "We selected ViroChem's compounds following careful evaluation of the STAT-C landscape for more than a year. Key data has emerged that suggest that these compounds could uniquely complement telaprevir and provide a foundation for shaping a potentially new treatment paradigm."

ViroChem HCV Drug Development Portfolio

Two ViroChem HCV polymerase inhibitors, VCH-222 and VCH-759, are currently in clinical development. ViroChem also has a preclinical program directed at the discovery of novel HCV NS5a inhibitors. The status and profile of each clinical compound is detailed below.

VCH-222: VCH-222 is an oral non-nucleoside inhibitor of the HCV NS5B polymerase that recently completed a viral kinetic study in HCV patients. In this study involving five treatment-naive genotype 1a and 1b HCV infected patients, VCH-222 dosed as 750 mg twice daily resulted in a median 3.7 log10 decrease in HCV RNA - equivalent to a 5,000-fold reduction in virus in the blood - at the end of three days of dosing. The results were consistent from patient to patient, and across HCV genotype 1 subtypes, and represent the most substantial reduction in viral load reported to date with an investigational HCV polymerase inhibitor dosed as a single agent. In clinical evaluations to date, VCH-222 has been well-tolerated, with no serious adverse events observed. VCH-222 has completed 28-day non-clinical toxicology studies in two species.

VCH-759: VCH-759 is an oral non-nucleoside inhibitor of the HCV NS5B polymerase that has completed Phase 1b clinical development. In a Phase 1b trial reported at a medical conference in 2007, VCH-759 dosed as 800 mg three times daily showed a mean maximal 2.5 log10 reduction in HCV RNA and a median 1.7 log10 reduction in HCV RNA at the end of 10 days. VCH-759 was also well-tolerated with no serious adverse events observed in clinical studies to date. VCH-759 has completed 28-day non-clinical toxicology studies.

Future clinical plans: Vertex plans to conduct additional dose-ranging studies of VCH-222 as a single agent and in combination with pegylated interferon and ribavirin. Vertex plans to initiate a first clinical study combining telaprevir with a ViroChem HCV polymerase inhibitor in the second half of 2009. Data from in vitro HCV replicon studies suggest that VCH-222 and VCH-759 may provide synergistic or additive antiviral activity to the HCV protease inhibitor telaprevir, thus creating the potential for a non-cross resistant, complementary profile in exploratory clinical studies.