Pharmasset and Roche Initiate New Toxicology Studies of HCV Polymerase Inhibitor
R7128
On
July 12, Pharmasset and Roche announced that they had begun a new round
of animal studies to evaluate the long-term safety of the investigational HCV
polymerase inhibitor R7128.
Below
is and excerpt from the Pharmasset press release:
Pharmasset and Roche Initiate Studies to Advance R7128
for HCV
PRINCETON,
New Jersey, July 12 --
PRNewswire -- Pharmasset, Inc. (Nasdaq: VRUS) announces the start
of long-term chronic toxicology studies in two animal species as part of their
collaboration with Roche for the development of R7128 for the treatment of hepatitis
C virus (HCV). R7128 is currently being evaluated in a Phase 1 clinical trial.
The primary objective of the chronic toxicology studies is to assess the safety
of R7128 when given for six months. Roche triggered a US$7.5 million milestone
payment to Pharmasset by initiating these studies.
"As
we progress the ongoing 14-day multiple ascending dose study of R7128, we are
encouraged that Roche has initiated the long-term chronic toxicology studies in
support of the potential advancement of R7128 into Phase 2 clinical trials,"
stated Schaefer Price, Pharmasset's President and CEO.
"This achievement is a clear indication that our cooperative partnership
with Roche is focused on the common
goal of accelerating the development of R7128 in order to bring new treatment
options to patients with hepatitis C."
About
R7128
R7128
is a polymerase inhibitor being developed for the treatment of chronic hepatitis
C. R7128 is a prodrug of PSI-6130, which demonstrated
potency in preclinical studies. PSI-6130 is a pyrimidine
nucleoside analog inhibitor of HCV RNA polymerase, an enzyme that is necessary
for hepatitis C viral replication. Results from an oral single ascending dose
study in 24 healthy male volunteers showed that PSI-6130 was generally well tolerated
with no serious adverse events in doses up to 3000 mg.
R7128
Phase 1 Study Overview
The
Phase I clinical trial is a multiple center, observer-blinded, randomized and
placebo-controlled study to investigate the pharmacokinetics, pharmacodynamics, safety, tolerability and food effect of
R7128 in healthy volunteers and in patients chronically infected with HCV genotype
1. This Phase 1 study is comprised
of two parts:
Part
1 is a single ascending dose study conducted in 38 healthy volunteers. The primary
objective of Part 1 is to assess the safety, tolerability and pharmacokinetics
of R7128 following single ascending doses under fasting conditions. The secondary
objective of Part 1 is to explore the effect of food on the pharmacokinetics of
R7128.
Preliminary
data from the single ascending dose portion of the study indicate:
·All doses
of R7128 studied were generally well-tolerated.
·All patients
completed the study with no gastrointestinal
adverse events or serious adverse events reported during the study.
·No hematological
or laboratory abnormalities of clinical significance were noted.
Part
2 is a multiple ascending dose study being conducted in up to 40 patients chronically
infected with HCV genotype 1 who have previously failed interferon therapy. The
primary objective of Part 2 is to assess the safety, tolerability and pharmacokinetics
of R7128 after once-daily or twice-daily dosing for 14 days. The secondary objective
is to assess antiviral efficacy by measuring the decrease in HCV RNA.
About
Pharmasset
Pharmasset
is a clinical-stage pharmaceutical company
committed to discovering, developing
and commercializing novel drugs to
treat viral infections. Pharmasset's primary focus is
on the development of oral therapeutics for the treatment of hepatitis B virus
(HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV).
Pharmasset
is currently developing three product candidates: Clevudine
for the treatment of chronic HBV infection, which is expected to enter US, European
and South American Phase 3 registration clinical trials and is already approved
for HBV in Korea and marketed by Bukwang Pharmaceuticals
under the brand name Levovir; R7128, an oral treatment
for HCV, in a Phase 1 clinical trial through a strategic collaboration with Roche;
and Racivir for the treatment of HIV in combination
with other approved HIV drugs, which has completed
a Phase 2 clinical trial.
