Full Press Release Details
Reduction in Viral Burden after HerpV Generated Immune Activation
trial in patients with genital herpes shows correlation between viral
load reduction and CD8 T cell activation, an important clinical
shows booster shot demonstrates sustainable, long-term effect
LEXINGTON, Mass.--(BUSINESS WIRE)--June 26, 2014--Agenus Inc. (Nasdaq:
AGEN), an immuno-oncology company developing a portfolio of checkpoint
modulators (CPMs), heat shock protein peptide-based vaccines, and
adjuvants, today announced promising Phase 2 results for HerpV, a
synthetic vaccine candidate for the treatment of patients with genital
Herpes Simplex Virus-2 (HSV-2). HerpV contains a defined mixture of
peptides representing HSV-2 antigens plus Agenus' QS-21 Stimulon
In a randomized, Phase 2, double-blind, multi-center study, the majority
of patients showed an immune response to the HSV antigens after a series
of vaccinations and a booster dose at six months. More than half of
those vaccinated developed a robust anti-HSV cytotoxic T-cell immune
response, and in those patients there was a statistically significant
75% reduction in viral load (P<0.001; CI: 46.2 - 88.6%). This level of
reduction in viral load has the potential to result in reduced incidence
and severity of herpetic outbreaks and a reduction in viral transmission1.
"We are pleased that the cellular immune response observed with HerpV
vaccination is associated with a significant reduction in viral
replication in the genital tract," said Robert Stein, MD, PhD, Chief
Scientific Officer of Agenus. "The fact that our vaccine contains
multiple HSV-2 antigens may contribute to its desired effects. We look
forward to advancing discussions with potential partners to take this
program into the next phase of clinical research."
After the booster shot, HerpV demonstrated a durable reduction in viral
shedding approximating 14% (RR=0.86 and CIs: 0.58-1.26) and remains
consistent with the reduction in viral shedding observed during the
initial treatment period. The protocol defined secondary analyses were
viral load and viral shedding after the booster shot, the primary
endpoint of the study was reported in November 2013.
In this study, the booster shot was given six months after the first
vaccination. Patients continue to be followed for safety and long-term
immune response. HerpV reported adverse events have mostly been in line
with expectations for a therapeutic vaccine and with effects commonly
associated with QS-21 Stimulon adjuvant. These adverse
events are short-lived and include flu-like symptoms and injection-site
About the Phase 2 HerpV Study
In November 2013, Agenus announced the trial met its primary endpoint
showing a statistically significant reduction in viral shedding. A total
of 80 subjects with a history of 1-9 herpes recurrences within the prior
12 months were randomized into the trial and 70 subjects received the
active treatment, HerpV and QS-21 Stimulon, and 10 subjects received
placebo. Three injections of HerpV at a dose of 240 g (includes12 g of
a mix of 32 different HSV-2 antigenic peptides) or placebo were given at
two week intervals. HSV-2 activity in the genito-urinary tract was
monitored by PCR for HSV-2 DNA in genital swabs for 45 days before and
after the initial course of three vaccinations.
The primary analysis, which looked at viral shedding after the initial
three HerpV vaccinations, demonstrated that subjects who received HerpV
had a statistically significant reduction in viral shedding (P=0.015;
RR=0.85). These results suggest a 15% reduction in viral shedding after
the initial treatment period before the administration of the booster
injection. The results also demonstrate a reduction in viral load of 34%
(P=0.08). Placebo patients showed no reduction compared to baseline in
either parameter. Notably, patients were not on any anti-viral
treatments during their swabbing period.
About Agenus' Heat Shock Protein Platform (HSP) and Recombinant
HerpV is a recombinant therapeutic vaccine for genital herpes caused by
the herpes simplex virus-2 (HSV-2). The vaccine is based on Agenus' HSP
platform technology, and contains Agenus' proprietary QS-21 Stimulon, a
plant-derived adjuvant that boosts specific immune responses. HerpV
consists of recombinant human heat shock protein-70 complexed with 32
distinct 35-mer synthetic peptides from the HSV-2 proteome. This broad
spectrum of herpes antigens is intended to allow for more accurate
immune targeting and surveillance, reducing the likelihood of immune
escape. Further, the diversity of antigens in HerpV increases the chance
of providing efficacy for a wide segment of the patient population.
About one in six Americans (16.2 percent) between the ages of 14 and 49
is infected with herpes simplex virus type 2 (HSV-2), according to the
Centers for Disease Control and Prevention (http://www.cdc.gov/std/Herpes/STDFact-Herpes.htm).
Herpes is the fastest growing STD in America, and experts predict that
one in four Americans will contract an STD sometime in their life. Since
two thirds of the population that gets herpes is age 25 or younger, it
is a real health threat to society. HSV-2 is a lifelong and incurable
infection that can cause recurrent and painful genital sores.
Agenus is an immuno-oncology company developing a portfolio of
checkpoint modulators (CPMs), heat shock protein peptide vaccines and
adjuvants. Agenus' checkpoint modulator programs target GITR, OX40,
CTLA-4, LAG-3, TIM-3 and PD-1. The company's proprietary discovery
engine Retrocyte Display is used to generate fully
human therapeutic antibody drug candidates. The Retrocyte Display
platform uses a high-throughput approach incorporating IgG format human
antibody libraries expressed in mammalian B-lineage cells. Agenus' heat
shock protein vaccines for cancer and infectious disease are in Phase 2
studies. The company's QS-21 Stimulon adjuvant
platform is extensively partnered with GlaxoSmithKline and Janssen and
includes several candidates in Phase 3 trials. For more information,
please visit www.agenusbio.com, or connect with the company on
Facebook, LinkedIn, Twitter and Google+. For more information, please
visit www.agenusbio.com.
Forward-Looking Statement
This press release contains forward-looking statements, including
statements regarding clinical trial activities and results and the
potential application of the Company's technologies and product
candidates in the prevention and treatment of diseases. These
forward-looking statements are subject to risks and uncertainties that
could cause actual results to differ materially. These risks and
uncertainties include, among others, the factors described under the