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Small
Study Shows HCV RNA Levels Undetectable in 12 of 12 HCV Genotype 1 Patients after
4 Weeks of Treatment with Experimental HCV Drug VX 950 Plus Pegasys and Ribavirin
By
Ronald Baker, PhD In
a highly encouraging announcement, Vertex Pharmaceuticals this week trumpeted
completion of a 12-patient, 28-day Phase II study of its experimental
oral HCV protease inhibitor VX-950 in combination with Pegasys
(pegylated interferon alfa-2a) and ribavirin. Preliminary
study results show that 12 of 12 patients
with HCV
genotype 1 had plasma HCV RNA levels below the limits of
detection of a highly sensitive assay (10 IU/mL;
Roche TaqMan) at 28 days of dosing, according to the
Vertex announcement. There
were no treatment discontinuations in the study and no serious
adverse
events were reported. The company said that a detailed
safety analysis of the study is ongoing.
Study
Design and Results The
Phase II clinical study enrolled 12 treatment-naïve patients with genotype 1 HCV.
Patients received VX-950 in a tablet formulation at a dose of 750 mg every eight
hours (q8h) for 28 days in combination with standard doses of pegylated interferon alfa-2a (180 microgram/wk) and ribavirin (800-1200 mg/day). At
the end of 28 days, patients completed dosing with VX-950. The study protocol
then required them to continue treatment with Pegasys
and ribavirin. This 28-day
Phase II study was not designed to evaluate sustained viral responses (SVR)
in patients receiving VX-950 [emphasis added—Ed]. For
patients entering the study, the distribution of baseline plasma HCV RNA values
was typical for a treatment-naïve patient population. At the end of week 1 (day
8 of VX-950 dosing), plasma HCV RNA was below the limit of quantitation
(30 IU/mL; Roche Taqman assay)
in 6 of the 12 patients; and undetectable (less than 10 IU/mL; Roche Taqman‚ assay) in 2 of
12 patients. Preliminary
HCV RNA results in patients for weeks 2-4 are as follows: ·
At the
end of week 2, plasma HCV RNA was below the limit of quantitation
(30 IU/mL) in 11 of the 12 patients; and undetectable
(less than 10 IU/mL) in 3 of 12 patients.
·
At
the end of week 3, plasma HCV RNA was below the limit of quantitation
(30 IU/mL) in 12 of the 12 patients; and undetectable
(less than 10 IU/mL) in 9 of 12 patients.
·
At
the end of VX-950 dosing (end of week 4; day 28), plasma HCV RNA was undetectable
(less than 10 IU/mL) in all 12 patients.
·
No
patients showed evidence of viral breakthrough while on treatment.Vertex
said the company plans to present the full data set from the 28-day Phase II study
at a medical conference later in 2006. The
Phase II study reported on today is the third in a series of clinical trials of
VX-950 in patients with HCV designed to evaluate safety, pharmacokinetics and antiviral activity. In addition, the
Company announced that it has completed three-month animal toxicology studies
that will support clinical studies of VX-950 of up to three months duration. According
to the company, initiation of additional Phase II clinical studies in the U.S.
in patients with HCV is planned following required Food and Drug Administration
(FDA) review of these latest non-clinical and clinical results, and FDA review
of a proposed clinical study protocol. "As
we look toward the end of 2006…, we expect to have generated data with VX-950
that supports the start of Phase III development in 2007,” stated Joshua Boger, PhD, Chairman, President and CEO of Vertex. 02/10/06 Source
Vertex Pharmaceuticals. Vertex Successfully Completes Key Studies with
VX-950 to Prepare for Next Steps in Clinical Program. Press Release. February 7, 2006.
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