Positive Results from TA-CD Cocaine Vaccine Trial Presented at CPDD
Slough, UK, 14 June 2004 - Xenova Group plc (London Stock Exchange:
XEN; NASDAQ: XNVA) announced today the presentation of results of two
dose escalation Phase II studies of TA-CD, a vaccine being developed
for the treatment of cocaine addiction, at the College on Problems of
Drug Dependence 66th Annual Scientific Meeting in Puerto Rico, June
12-17. Presented by Dr Bridget Martell, the trials were carried out
by Professor Thomas Kosten and his team at Yale University School of
The two open-labelled, dose-escalation studies carried out on an
out-patient basis, evaluated safety, immunogenicity and clinical
efficacy of TA-CD in a total of 22 cocaine users. One of the two
studies comprised nine cocaine dependent subjects receiving the TA-CD
vaccine and assessed for relapse prevention; these subjects were
required to have been free of cocaine use for the two weeks prior to
entering the study. The second study included 13 cocaine dependent
subjects for abstinence initiation, who were not required to have
negative urine cocaine tests prior to enrolment.
Subjects received between three 100 mcg doses and five 400 mcg doses
of the TA-CD vaccine (up to 2000 mcg in total). TA-CD was well
tolerated in the 20 subjects who completed the two studies.
Results from both studies showed that the maximum mean antibody
response occurred between 70 and 90 days post vaccination with
specific cocaine antibodies persisting for at least six months.
Eight subjects also received a booster 15-18 months post vaccination
with TA-CD, all of whom showed increased levels of antibodies two to
four weeks later.
Three quarters (75%) of the relapse prevention study group maintained
abstinence from cocaine use during the 12-week study duration with
100% relapsing after 12 months when antibody levels had dropped.
In the abstinence initiation study group, 58% achieved and maintained
abstinence during the 12-week study and 42% continued to be cocaine
free after six months.
The authors additionally reported that the likelihood of using
cocaine decreased in those subjects who received a more intense
vaccination schedule and as a result were observed to produce higher
levels of anti-cocaine antibodies. 88% of subjects in one study and
63% of subjects in the other, who relapsed within six months,
reported a reduction in the euphoric effects of cocaine.
Bridget Martell, MD, MA, Associate Research Scientist at Yale
University and involved in the TA-CD trials said, "Cocaine dependent
users have a serious need for assistance with achieving and
maintaining abstinence. We are impressed with these results which,
although on a comparatively small number of subjects, are
particularly significant as a number of addicts receiving the TA-CD
vaccine were able to remain abstinent during the study periods."
David Oxlade, Chief Executive Officer of Xenova said, "These very
encouraging results give a strong indication of proof of concept for
the TA-CD cocaine vaccine and further validate its potential in
assisting cocaine addicts to achieve abstinence."
This study was supported by the US National Institute of Drug Abuse
(NIDA). NIDA has also supported earlier clinical work on TA-CD.
NIDA has no rights to the commercialisation of TA-CD nor is funding
required to be repaid by Xenova.
Xenova Group plc +44 (0)1753 706600
David A. Oxlade, Chief Executive Officer
Daniel Abrams, Finance Director
Veronica Cefis Sellar, Headof CorporateCommunications
UK- Financial Dynamics +44 (0)20 7831 3113
US- Trout Group/BMC Communications
+1 212 477 9007
Media: Brad Miles
Investors: Lee Stern
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 products in clinical development, including three cancer
programmes: its lead product 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 employs approximately 112 people throughout
its sites in the UK and North America. (Reuters XEN.L; Bloomberg XEN
For further information about Xenova and its products please visit
the Xenova website at www.xenova.co.uk.
Notes to Editors
The Office of National Statistics estimate that there are currently
475,000 powder cocaine and 200,000 crack cocaine addicts in Britain.
UK Government figures indicate that deaths caused by Class A drugs
rose from 96 in 2001 to 139 in 2002 and that deaths from cocaine
poisoning have more than doubled with medical evidence that cocaine
causes the heart to age prematurely and leads to the rupture of blood
vessels. According to Home Office figures, more than 3 million
people in the UK spend a total of £6.6 billion on illegal drugs per
In the US, it is estimated that there are approximately 1.7 million
addicts, some 3 million occasional users and about 900,000 cocaine
users seek medical help for their cocaine addiction every year (Lewin
Group report from 1997 based on data from SAMHSA Substance Abuse
Mental Health Services Administration).
The US Department of Health and Human Services 2002 National Survey
on Drug Use found that more than 33 million people age 12 and older
had used cocaine at least once in their lifetime. According to What
America's Users Spend in Illegal Drugs, users spent $35.3 billion on
cocaine in 2000, consuming 259 metric tons of cocaine
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