Wake-up News....
HYBRIDON MOVES GEM(R) 91 INTO CONFIRMATORY CLINICAL TRIAL
In Advanced HIV-Positive Patients
Announcement Made at Antisense Therapeutics Meeting in San Diego
CAMBRIDGE, Mass., Feb. 6 /PRNewswire/ -- Hybridon, Inc. (Nasdaq: HYBN)
today announced that its lead compound, GEM(R) 91, is moving into a
confirmatory Phase II clinical trial in advanced HIV-positive patients.
The announcement was made at the "Oligonucleotide and Gene
Therapy-based Antisense Therapeutics" meeting in San Diego where Dr.
Russell Martin, Hybridon Vice President for Clinical Research,
presented promising virological results obtained in its ongoing Phase
Ib/II study of GEM(R) 91.
The decision to conduct a confirmatory trial was influenced by an
analysis of available data by an independent biostatistician, Dr.
Victor DeGruttola, Professor of Statistics at the Harvard School of
Public Health. Dr. DeGruttola evaluated unblinded data from Hybridon's
ongoing Phase Ib/II clinical trial comparing GEM(R) 91 with placebo
treatment, and supports the Company's plan to unblind and publish data
for the completed cohorts.
"Based on a statistically significant decrease in cellular viremia
between treated and untreated patients with advanced HIV disease in
these trials, which returned toward baseline after treatment, Dr.
DeGruttola supports Hybridon's plan to conduct a confirmatory trial in
more severely affected patients," Dr. Martin said. "An additional
finding was that the plasma concentration of viral RNA showed a
moderate increase during treatment, which promptly reversed after
therapy."
Dr. Robert Coombs, Associate Professor, Department of Laboratory
Medicine at the University of Washington in Seattle, has been
conducting quantitative cellular viremia determinations for the GEM(R)
91 studies. "Virological tests performed to measure infectious virus
in the circulating white blood cells represent the 'gold standard' to
measure antiviral activity," Dr. Coombs said. "Seeing a drop in
cell-associated virus with GEM(R) 91 treatment is an encouraging
finding."
Commenting on the results of GEM(R) 91 clinical trials to date, Dr.
Martin said, "The observation that late stage patients respond to
GEM(R) 91 could be due to the fact that, when given systemically,
GEM(R) 91 concentrates in macrophages. These cells are emerging as an
important location of the ongoing, residual component of infection that
persists after combination therapy."
The goal of the Phase II trial is for Hybridon to confirm the results
from the ongoing Phase Ib/II study, prior to initiating pivotal trials
later this year, according to E. Andrews Grinstead, Chairman and CEO.
"Subsequently, we intend to apply for a treatment IND for the use of
GEM(R) 91 for AIDS patients who, for whatever reason, are failing to
respond to other therapies," Mr. Grinstead said. AIDS patients may
fail to respond to currently available combination therapy due to viral
resistance or intolerance.
Hybridon believes GEM(R) 91 is distinctive in that it is both targeted
to HIV's genetic message and is designed to inhibit HIV-1 replication
at multiple stages. In cell culture studies, GEM(R) 91 has been shown
to: 1) inhibit virion binding to cells, 2) interfere with the reverse
transcription of viral RNA leading to integration, and 3) reduce virus
production by blocking the gag-messenger RNA of HIV-1. This inhibition
of HIV-1 replication by GEM(R) 91 is primarily due to an antisense
mechanism at both early and late stages of the virus replication cycle,
with additional non-antisense effects at the virus absorption stage.
In contrast to GEM(R) 91, all currently available antiretrovirals
(reverse transcriptase and protease inhibitors) are enzyme inhibitors
with single sites of action.
Data on this multiple mechanism of action and the absence of viral
resistance in vitro with GEM(R) 91 in comparison to AZT and protease
inhibitors have been demonstrated by a team of Hybridon and Harvard
Medical School researchers. Some of these results will be published in
April. More recently, the researchers have demonstrated in a cell
culture assay that GEM(R) 91 acts synergistically to make selected RT
inhibitors 100-fold more potent than when used alone.
In addition to intravenous studies with GEM(R) 91, Hybridon conducted
clinical trials in France and the United Kingdom with an intramuscular
(IM) formulation. Encouraged by the results of these trials, Hybridon
has proceeded with the development of an improved IM formulation of
GEM(R) 91. The availability of this formulation, which is expected this
year, could allow chronic treatment using GEM(R) 91 on an outpatient
basis.
As clinical development continues with both IV and IM formulations of
GEM(R) 91, Hybridon is proceeding with preclinical development of a
second generation, GEM(R) 92, based on Hybridon's patented "hybrid"
antisense chemistry which has been shown in in vivo studies to superior
metabolic stability. Orally administered hybrid oligonucleotides have
been shown to be active in animal models of a different disease.
GEM(R) 92 is also being tested following oral administration and
Hybridon intends to file an IND for the compound during the fourth
quarter of '97.
Hybridon, headquartered in Cambridge, Massachusetts, is a leader in the
discovery, development and commercialization of novel genetic medicines
for the treatment of diseases for which there are currently limited or
no effective treatments. The Company has also launched a custom
manufacturing division, Hybridon Specialty Products. In addition to
GEM(R) 91, the Company has in clinical development two different
formulations for an advanced chemistry antisense oligonucleotide,
GEM(R) 132, for systemic CMV infection and CMV-induced retinitis in
AIDS patients. Antisense technology involves the use of synthetic
segments of DNA to stop the production of disease-associated proteins
by interacting at the genetic level with target strands of messenger
RNA.
This press release contains forward-looking statements that involve a
number of risks and uncertainties. For this purpose, any statements
contained herein that are not statements of historical fact may be
deemed to be forward- looking statements. Without limiting the
foregoing, the words "believes," "anticipates," "plans," "expects,"
"intends" and similar expressions are intended to identify
forward-looking statements. Important factors that could cause actual
results to differ materially from those indicated by such
forward-looking statements are set forth under the caption "Certain
Factors That May Affect Future Results" in the Company's Annual Report
on Form 10-K for the year ended December 31, 1995, which important
factors are incorporated herein by reference. As more fully described
in such "important factors" discussion in the Company's Annual Report
on Form 10-K, please note that all of the Company's potential products
are at an early stage of development, the results obtained in
preclinical studies and early clinical studies such as the preliminary
results obtained from the cell culture and animal studies and the
clinical trials of GEM(R) 91 referred to above may not be indicative of
results that will be obtained in later clinical trials, neither the
Company, nor to its knowledge, any other company has successfully
completed human clinical trials of a product based on antisense
technology, and there can be no assurance that the Company will receive
regulatory approvals to commence or continue clinical trials of product
candidates or to market any products.
SOURCE Hybridon, Inc.
-0- 2/6/97 /NOTE TO EDITORS: This release
is available on the Internet at hybridon.com and
noonanrusso.com
/CONTACT: Robin Hogen, Vice President Corporate Communications and
Public Affairs of Hybridon, Inc., 617-528-7504; or Barbara Lindheim of
Noonan/Russo Communications, Inc., investors, 212-696-4455, ext. 237,
or e-mail: news@noonanrusso.com/
(HYBN)
CO: Hybridon, Inc. ST: Massachusetts, California IN: MTC SU:
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