Pharmasset Announces Submission of Abstracts to AASLD Liver Meeting Including an Interim Analysis of Roche's Phase 2b PROPEL Trial of RG7128
-- Analysis of data by Roche from all 408 patients concluded safety and tolerability profile of RG7128 administered for 8 or 12 weeks with standard of care (SOC) continues to be similar to SOC alone -- RG7128 in combination with SOC demonstrated highly potent antiviral effects greater than SOC alone, patients with either HCV genotype 1 or 4 -- Roche has submitted two RG7128 abstracts to AASLD for the Annual Liver Meeting
PRINCETON, N.J., June 09, 2010, /PRNewswire-FirstCall/ --
Pharmasset, Inc. (NASDAQ:VRUS) announced today that the interim
results from the PROPEL study conducted by its partner Roche
demonstrate that RG7128 triple combination therapy was safe and
well tolerated. In that study, the safety profile of RG7128 (1000mg
BID or 500mg BID), when administered for 8 or 12 weeks with Pegasys
(peginterferon alfa-2a) and Copegus (ribavirin), the standard of
care (SOC), was similar to the safety profile of SOC alone. An
interim analysis of the study included all safety data from all 408
patients who had completed the first 12 weeks of the study. The
most common adverse events were no different than those frequently
noted with SOC alone. There were no findings related to rash,
anemia, bone marrow suppression, or nephrotoxicity across any of
the arms.
The PROPEL study is evaluating the dose and duration of
treatment of RG7128 in combination with SOC in patients with
chronic hepatitis C virus (HCV) genotype 1 or genotype 4 who have
not been treated previously. The interim analysis also included
on-treatment efficacy data demonstrating that >80% of patients
had undetectable HCV RNA in all cohorts receiving the 12-week
triple regimen compared to <50% for the placebo/SOC cohort. The
safety and efficacy results from the interim analysis of the PROPEL
Phase 2b study of RG7128 have been submitted by Roche as an
abstract to AASLD for the Annual Liver Meeting (October 29 to
November 2, 2010). The title of the abstract is:
"High rates of early viral response, promising safety profile
and lack of resistance-related breakthrough in HCV GT 1/4 patients
treated with RG7128 plus PegIFN alfa-2a (40KD)/RBV: Planned Week 12
interim analysis from the PROPEL study"
"We are encouraged by the reported efficacy, safety, and
resistance data from this interim analysis of the PROPEL study,"
said M. Michelle Berrey, MD, MPH, Pharmasset's Chief Medical
Officer. "We believe safety, absence of resistance, as well as
antiviral potency will all be important considerations as HCV
treatment incorporates direct acting antivirals in combination with
interferon, and in potential interferon-free antiviral combination
regimens."
No viral rebounds or resistance-related breakthroughs were noted
during the first 8 or 12 weeks of triple combination therapy,
consistent with the demonstrated high barrier to resistance in
earlier RG7128 clinical studies. In clinical reports to date, the
S282T mutation associated with RG7128 resistance in vitro has not
been detected at baseline in HCV-infected patients enrolling in
clinical trials. A separate abstract has been submitted by Roche
including details of the resistance analyses that have been
conducted during this study, including sequencing of the HCV RNA
from all patients at baseline. The abstract is entitled:
"No evidence of drug resistance or baseline S282T resistance
mutation among GT1 and GT4 HCV infected patients on nucleoside
polymerase inhibitor RG7128 and Peg-IFN/RBV combination treatment
for up to 12 weeks: interim analysis from the PROPEL study."
About the Phase 2b PROPEL Study
The Phase 2b study enrolled 408 patients with HCV genotypes 1 or 4, cirrhotic and non-cirrhotic, who have not been treated previously. The primary efficacy endpoint of the study is the proportion of patients who achieve an SVR, defined as HCV below the limit of detection (<15 iu>
-- 24 weeks of total treatment; RG7128 500mg BID in combination with SOC
for 12 weeks, followed by 12 weeks of SOC ("12+12", RVR guided)
-- 24 weeks of total treatment; RG7128 1000mg BID in combination with SOC
for 12 weeks, followed by 12 weeks of SOC ("12+12", RVR guided)
-- 24 weeks of total treatment; RG7128 1000mg BID in combination with SOC
for 8 weeks, followed by a further 16 weeks of SOC ("8+16", RVR
guided)
-- 48 weeks of total treatment; RG7128 1000mg BID in combination with SOC
for 12 weeks, followed by a further 36 weeks of SOC ("12+36", non-RVR
guided")
-- A control arm with SOC for 48 weeks.
Patients in the 24-week arms will discontinue all treatment at week 24 if they have achieved RVR, defined as HCV RNA below the limit of detection (<15 iu>
RG7128 is also currently being evaluated in a Phase 2b study in
which RG7128 and SOC are given for a total of 24 weeks each
("24+0", RVR guided). The regimen will be assessed in
treatment-naive HCV-infected patients with genotypes 1 or 4.
Enrollment in this study was completed in early May. In addition,
Roche anticipates the initiation of another Phase 2 study in
HCV-infected patients with genotypes 2 or 3 by the end of
2010.
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 C
virus (HCV) and, secondarily, on the development of Racivir(TM) for
the treatment of human immunodeficiency virus (HIV). Our research
and development efforts focus on nucleoside/tide analogs, a class
of compounds which act as alternative substrates for the viral
polymerase, thus inhibiting viral replication. We currently have
four clinical-stage product candidates. RG7128, a cytosine analog
for chronic HCV infection, is in two Phase 2b clinical studies in
combination with Pegasys(R) plus Copegus(R) and is also in the
INFORM studies, the first series of studies designed to assess the
potential of combinations of small molecules without Pegasys(R) and
Copegus(R) to treat chronic HCV. These clinical studies are being
conducted through a strategic collaboration with Roche. Our other
clinical stage HCV candidates include PSI-7977, an unpartnered
uracil nucleotide analog that has recently completed a Phase 2a
study, and PSI-938 an unpartnered guanine nucleotide analog in
Phase 1. We also have in our pipeline an additional purine
nucleotide analog, PSI-661, an isomer of PSI-879, in advanced
preclinical development. Racivir, for the treatment of HIV, has
completed a Phase 2 clinical study.
Pegasys® and Copegus® are registered trademarks of Hoffman-La Roche, Inc.
Contact
Richard E. T. Smith, Ph.D.
VP, Investor Relations and Corporate Communications
Office: +1 (609) 613-4181
Forward-Looking Statements
Pharmasset "Safe Harbor" Statement under the Private Securities
Litigation Reform Act of 1995: Statements in this press release
that are not historical facts are "forward-looking statements,"
including, without limitation, statements that involve risks,
uncertainties, and other important factors, including, without
limitation, the risk of cessation or delay of any of the ongoing or
planned clinical trials and/or our development of our product
candidates, the risk that the results of previously conducted
studies involving our product candidates will not be repeated or
observed in ongoing or future studies involving our product
candidates, the risk that our collaboration with Roche will not
continue or will not be successful, and the risk that any one or
more of our product candidates will not be successfully developed
and commercialized. For a discussion of risks, uncertainties, and
other important factors, any of which could cause our actual
results to differ from those contained in the forward-looking
statements, see the section entitled "Risk Factors" in our Annual
Report on Form 10-K for the fiscal year ended September 30, 2009
and our Quarterly Reports on Form 10-Q for the periods ended
December 31, 2009 and March 31, 2010 filed with the Securities and
Exchange Commission and discussions of potential risks,
uncertainties, and other important factors in our subsequent
filings with the Securities and Exchange Commission.
Source: Pharmasset, Inc.
CONTACT: Richard E. T. Smith, Ph.D., VP, Investor Relations
and
Corporate Communications of Pharmasset, Inc., +1-609-613-4181
Web Site: http://www.pharmasset.com/
Posted: June 2010
