Pharmasset Reports Phase 2 HIV Study Results of Reverset(TM): Once-Daily Oral
Dose Reduced HIV Viral Load by 1.77 Log(10) copies/mL
ATLANTA, Feb. 11 /PRNewswire/ -- Pharmasset, Inc. today announced results from
a Phase 2 study of Reverset, which is being co-developed with Incyte Corporation
for the treatment of HIV-infected patients. The data was presented at the 11th
Conference on Retroviruses and Opportunistic Infections in San Francisco by
clinical investigator Robert Murphy, M.D., Professor ofInfectious Diseases at
Northwestern University. The study demonstrated a marked reduction in viral load
of more than 1.7 log(10) after 10 days of monotherapy treatment with no serious
drug related adverse events.
"Reverset is a drug with the potentialto be the best in its therapeutic class. It is one of the most potent and promising anti-HIV agents in clinical
development," remarked inventor and Professor Raymond F. Schinazi.
Reverset, a nucleoside analog that targets the HIV-1 reverse transcriptase
enzyme, is being developed under an approved US FDA Investigational New Drug
(IND) application for the treatment of HIV-infected individuals. Preclinical in
vitro studies have shown that Reverset inhibits replication of drug-resistant
HIV strains commonly seen after treatment with zidovudine (ZDV) and lamivudine
(3TC).
About the Study Design A total of 30 HIV-infected, treatment-naive individuals with CD4(+) cell counts
> 50 cells/mm(3) and plasma HIV-1 RNA levels > 5,000 copies/ml were enrolled in
a 10-day monotherapy dose escalation study. Subjects were randomized to one of
three dose levels of Reverset - 50 mg, 100 mg, or 200 mg, or placebo, once-a-day
for 10 days. Study medication was administered in a double-blind fashion. Plasma samples were taken for HIV-1 RNA predose, on days 1, 2, 4, 8, 10 of
treatment, and on days 11, 14, 21, 28 and 38 in the follow-up phase. Plasma
samples for virus genotyping were taken at baseline, at the end of treatment,
and at the follow-up visits. Pharmacokinetic samples were obtained over the
first 24 hours of dosing and again on day 10.
Phase 2 Study Results Preliminary results from this ongoing study showed plasma pharmacokinetic values
were linear with dose on days 1 and 10 of dosing. Mean day 10 plasma C(max)
levels were 2.3 uM, 5.4 uM and 9.8 uM for the 50 mg, 100 mg and 200 mg daily
doses, respectively. The mean viral load declines at the end of the treatment
phase for the three dose levels were 1.67 plus or minus 0.24 log(10) at 50 mg,
1.74 plus or minus 0.32 log(10) at 100 mg, and 1.77 plus or minus 0.23 log(10)
at 200 mg, with maximum decreases ranging from 1.2 to 2.3 log(10). Viral RNA
levels slowly returned to baseline during the follow-up period. CD4(+) cell
counts increased during the treatment phase, but returned to pretreatment levels
during the follow-up period. No serious drug-related adverse events were
reported and all adverse events were mild or moderate and occurred at similar
incidences in the active and placebo groups.
"Thepotent in vivo antiviral activity and safety in the current study coupled
with the in vitro susceptibility of drug-resistant HIV to Reverset is very
encouraging. We are optimistic that the next study in antiretroviral-experienced
subjects will further confirm the drug's activity on a broader patient
population," noted Dr. Michael Otto, Pharmasset's Chief Scientific Officer.
"Pharmasset has diligently managed the clinical development of Reverset through
this Phase 2 study, which is further testament to the company's business and
scientific goals of successfully advancing new therapeutics for life-threatening
diseases from discovery to the clinic," stated Dr. Abel De La Rosa, Pharmasset's
Senior Vice President of Business and Scientific Development."Going forward,
our strategic collaborative license agreement with Incyte will provide the added
support and clinical expertise to continue the rapid development of Reverset
toward regulatory approval and commercialization." On September 8, 2003, Pharmasset and Incyte (NASDAQ:INCY) announced a
collaborative license agreement to develop and commercialize Reverset. Pharmasset will receive from Incyte future performance milestone payments and
royalties on net sales in exchange for exclusive rights in the U.S., Europe and
certain other markets to develop, manufacture and market the drug. Pharmasset
retained development, marketing and commercialization rights in certain
territories, including Mexico, Central and South America, Africa, the Middle
East, Korea and China.
About Pharmasset Pharmasset (http://www.pharmasset.com/) is an antiviral and anticancer drug
discovery, development, and commercialization company. Pharmasset is committed
to the development of novel, patentable, proprietary nucleoside chemical agents
as treatments for life-threatening diseases, such as HIV, hepatitis viruses and
cancers. Pharmasset currently guides the preclinical and clinical development of
its proprietary small molecule technologies up to Phase 2/3 clinical trials.
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PRESS RELEASE. DATASOURCE: Pharmasset, Inc.
CONTACT: Alan Roemer of Pharmasset, Inc., +1-678-395-0035 or Web site: http://www.pharmasset.com/
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