Slough, UK, 3 March 2005 - Xenova Group plc (NASDAQ: XNVA; London
Stock Exchange: XEN) today announced preliminary 12 month findings
from the second Phase I trial of TA-NIC, the Company's therapeutic
vaccine being developed for the treatment of nicotine addiction.
A total of 60 subjects who smoked between 10 and 75 cigarettes a day
were recruited into the trial, divided into three cohorts. Within
each cohort of 20 smokers, 16 received the active vaccine and 4
received the placebo. The primary objectives of the study were to
evaluate the safety, tolerability and immunogenicity vs. placebo of
three doses of TA-NIC - 50 �g, 250 �g and 1000 �g. The vaccine was
administered by intramuscular injection at weeks 0, 2, 4, 6, 8 and 12
with a booster at 32 weeks.
Secondary objectives included recording the number of cigarettes
smoked per day, determining the time to first cigarette and the time
to relapse following a quit attempt at week 12 and if necessary
another quit attempt at week 32. These quit rates were then assessed
again after 12 months
Initial 20 week immunogenicity data and other findings were reported
in July 2004.
The data announced today show that
* 12 month self-reported quit rates were substantially greater
amongst those receiving TA-NIC than those receiving placebo. None
of the participants receiving TA-NIC or the placebo received
counselling, nicotine replacement therapy or any other aid to
quit smoking as part of the study.
In the placebo group, 1 out of 12 participants (8%) reported being
abstinent at their last visit or at 12 months compared with 3 out of
16 (19%) and 6 out of 16 (38%) in the two groups receiving the
higher doses of TA-NIC.
* Additionally, the proportion of participants who successfully
made a quit attempt was higher amongst those receiving TA-NIC
(95%) than amongst those receiving the placebo (73%).
* A booster, given at 32 weeks, produced a substantial and
sustained increase in nicotine specific antibodies in both groups
receiving the higher doses of TA-NIC.
* Immunogenicity data after 12 months follow up and the safety and
tolerability profile support the 20 week findings announced in
July 2004, and confirm the selection of the 250 �g dose for use
in the Phase II and III clinical trials.
Following these preliminary results and confirmation of the dose to
be taken forward, Xenova expects to begin Phase II trials for TA-NIC
this year with interim Phase II results expected in 2006.
David Oxlade, Chief Executive Officer of Xenova said: "Although this
study was not primarily set up to assess the long term quit rates
amongst smokers receiving TA-NIC, we are pleased to observe these
promising findings and the confirmation of the selected dose for
further clinical trials. There is an urgent need for a more
effective treatment for nicotine addiction, with almost 5 million
people dying each year from tobacco use and over 1 billion people
globally still smoking,"
Notes to Editors
The World Health Organisation (WHO) notes that the tobacco epidemic
is still expanding, especially in developing countries where
currently 84% of smokers live. Tobacco use kills 4.9 million people
each year and this toll is expected to double in the next 20 years.
At current rates, the total number of tobacco users is expected to
rise to 1.7 billion by 2025 from 1.3 billion now (May 2004).
Of the 1.3 billion smokers globally, it is estimated that some 4
million smokers each year in the UK attempt to quit, but that only
3-6% (or 1-2% of all smokers) are successful in giving up tobacco.
Conventional treatment of nicotine addiction concentrates on
psychosocial interventions (counselling, smoking cessation clinics)
together with pharmacotherapy, including nicotine replacement therapy
(NRT) and bupropion (Zyban�, GlaxoSmithKline). Even with effective
behavioural and pharmacological therapies, many individuals dependant
on nicotine fail in their attempts to remain abstinent, with smoking
cessation rates of only approximately 10-20% at 1 year.
Inhaled nicotine is highly addictive. Absorption of nicotine from
cigarette smoke through the lung is rapid, producing with each
inhalation a high concentration arterial bolus of nicotine that
reaches the brain within 10-16 seconds, faster than by intravenous
injection. Nicotine is able to cross the blood brain barrier where
it binds to acetyl-choline receptors, triggering the release of
neurotransmitters, such as dopamine and serotonin. These give rise
to positive feelings (pleasure, relaxation, lack of anxiety,
suppressed appetite, improved concentration) which are reinforced
with each cigarette. Nicotine has a distribution half life of 15-20
minutes and a terminal half life in the blood of two hours. Smokers
therefore experience a pattern of repetitive and transient high blood
nicotine concentrations from each cigarette, with regular hourly
cigarettes needed to maintain raised concentrations, and overnight
blood levels dropping near to those of non-smokers. Smoking
cessation is difficult to achieve due to the addictive properties of
nicotine and the unpleasant withdrawal symptoms (irritability, lack
of concentration, weight gain, nicotine craving).
TA-NIC mode of action
TA-NIC is a therapeutic vaccine in development for the treatment of
nicotine addiction. Nicotine is a small molecule which, by itself,
does not trigger an immune response. However, when nicotine is
carried by an immunogenic protein it can prime the immune system to
produce anti-nicotine antibodies. The active ingredient of TA-NIC
vaccine is a protein conjugate: nicotine butyric acid (NBA)
covalently linked to recombinant cholera toxin B (rCTB). rCTB was
chosen as the carrier protein because it is known to be highly
immunogenic and has been used for many years as a component of
cholera vaccine. rCTB has been approved by the Swedish Medical
Products Agency for use in an oral cholera vaccine that is marketed
in Sweden and Norway and in 2003 was approved by the CPMP.
Nicotine is bound by the induced circulating anti-nicotine antibodies
in the bloodstream and the resulting antigen-antibody complex is too
large to cross the blood-brain barrier, so the pleasurable stimulus
which usually accompanies smoking will be absent or reduced. Without
this reward, the motivation to smoke again is reduced, preventing the
reinforcement which is required to maintain the nicotine addiction.
NICE Guidance on the use of nicotine replacement therapy (NRT) and
bupropion for smoking cessation. March 2002
World Health Organisation, An International Treaty for Tobacco
Control, 12 August 2003
Xenova Group plc is a UK-based biopharmaceutical company focused on
the development of novel drugs to treat cancer and addiction with a
secondary focus in immunotherapy. The Company has a broad pipeline
of product candidates in clinical development, including three cancer
programmes: its lead product candidate TransMIDTM, for the treatment
of high-grade glioma, is in Phase III trials, and its novel DNA
targeting agents and XR303 are both in Phase I for cancer
indications. Xenova is also developing two therapeutic vaccines for
cocaine and nicotine addiction, which are in Phase II and Phase I
trials respectively. Quoted on the London Stock Exchange (XEN) and
on NASDAQ (XNVA), Xenova has approximately 75 full time employees in
the UK and North America. (Reuters XEN.L; Bloomberg XEN LN).
For further information about Xenova and its products please visit
the Xenova website at www.xenova.com and www.gbmtrial.com
This press release contains "forward-looking statements," including
statements about the development and commercialization of products.
Various risks may cause Xenova's actual results to differ materially
from those expressed or implied by the forward looking statements,
including: adverse results and delays in our drug discovery and
clinical development programs; failure to obtain effective patent
protection for our discoveries; commercial limitations imposed by
patents owned or controlled by third parties; failure to achieve
product development or commercialization milestones on a timely basis
or at all; our dependence upon strategic alliance partners to
develop and commercialize products and services; difficulties or
delays in obtaining regulatory approvals to market products and
services resulting from our development efforts; the requirement for
substantial on-going funding to conduct research and development and
to expand commercialization activities; and product initiatives by
competitors. For a further list and description of the risks and
uncertainties we face, see our reports on file with the Securities
and Exchange Commission. We disclaim any intention or obligation to
update or revise any forward-looking statements, whether as a result
of new information, future events or otherwise.
 Smokers who reported that they were no longer smoking at their
last visit or at 12 months
Xenova Group plc
+44 (0)1753 706600
David A. Oxlade, Chief Executive Officer
Daniel Abrams, Finance Director
Veronica Cefis Sellar, Head of Corporate Communications
UK - Financial Dynamics
+44 (0)20 7831 3113
US - Trout Group/BMC Communications
+1 212 477 9007
Media: Brad Miles
Investors: Lee Stern
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