Clinical update

Allergy Therapeutics PLC
24 March 2006



                            Allergy Therapeutics plc

      Positive outcome of pivotal Pollinex(R) Quattro Ragweed study - R204

Allergy Therapeutics plc, the specialist pharmaceutical company focused on 
allergy vaccination, today announces that it has achieved a positive outcome for 
its key clinical efficacy and safety study R204.

The R204 study is a crucial part of the company's development of their ultra 
short course allergy vaccines, Pollinex Quattro.  These four shot products are 
based on MPL(R), the company's innovative TLR4-agonist which acts as an 
efficient allergy vaccine adjuvant.  Pollinex Quattro Ragweed is designed to 
treat patients allergic to ragweed pollen. It is estimated that more than 30 
million people in North America suffer from allergies to ragweed. The Pollinex 
Quattro allergy vaccines, which require only four injections per year, have the 
potential to transform allergy treatment, by providing a convenient, safe, 
effective and potentially curative method of vaccination.


The positive R204 study results mark an important step in the development of
Pollinex Quattro for ragweed allergy. In addition, the R204 outcome:

   • supports the Company's application for registration in Canada planned
    for the middle of 2006;

   • is a key element in "End of Phase II" discussions with the FDA and other
    authorities prior to initiating Phase III;

   • contributes to the data on safety and efficacy of the company's other
    ultra short course Pollinex Quattro vaccines in Grass and Tree, which are
    also in development.


The R204 study was conducted in an Environmental Exposure Chamber (EEC). A group
of 177 ragweed sensitive patients were exposed to controlled quantities of
ragweed pollen to simulate a heavy pollen day and their reactions before and
after treatment were compared. The initial results of this study demonstrate
that Pollinex Quattro Ragweed was well tolerated and significantly reduced
clinical symptoms compared with placebo. The Pollinex Quattro treatment group
total symptom score had fallen to 9.1 from a baseline of 15.7. The 'primary
endpoint' of the study, this change from baseline in the active treatment group,
was statistically significant (p<0.01) compared with placebo and demonstrates a
clinically significant 42% improvement in symptoms and a 48% relative
superiority over placebo. These results represent an improvement in the average
patient's symptoms from 'moderate' to 'mild', and will shortly be augmented with
further ongoing analyses of secondary outcomes. In addition to these clinical
results, a highly significant immunological response (increase in serum IgG) was
observed (p<0.001).


Commenting on today's announcement, Dr. Piyush Patel, Principle Scientist,
Medical Monitor for the study and Allergist, said:

"Ragweed is the major allergen in North America and the cause of a great deal of
suffering. The EEC is a particularly rigorous test methodology for studying
allergy and medication efficacy. Testing involves real patients, real pollen,
real symptoms and this study has demonstrated a real clinical benefit. The
treatment schedule and speed of action of this ultra short course therapy should
translate into rapid acceptance."


Dr Tom Holdich, Allergy Therapeutics' R&D Director, commented:

"This is the climax of all the pre-Phase III work that we have conducted over
the last year and probably the most important data that we have generated in the
last 5 years. North America is now firmly in our sights. It's a fantastic shot
in the arm"


Keith Carter, Allergy Therapeutics' Chief Executive Officer, said:

"I am delighted to be able to deliver such positive news. Today's announcement
is a landmark step in the process for achieving global registration and launches
for Pollinex Quattro. We have tremendous confidence in Pollinex Quattro which
has already sold over 143,000 treatment sets and successfully treated over
74,000 patients. This is an exciting time for Allergy Therapeutics as we
continue to make good progress in the development of our entire pipeline of
innovative MPL-based vaccines all of which will help in bringing allergy
vaccination into the mainstream"


                                     -ends-


For further information:


Allergy Therapeutics plc

Keith Carter, Chief Executive Officer                        [phone]


Bell Pottinger

Dan de Belder/Emma Charlton                                  [phone]



About the R204 Study


R204 is a double-blind, placebo controlled, Phase IIb study to evaluate the
clinical efficacy and safety of Pollinex Quattro Ragweed using an Environmental
Exposure Chamber. The trial included 188 patients with a history of moderate to
severe seasonal rhinoconjunctivitis, a positive skin prick test and a positive
radioallergosorbent test (RAST) to ragweed allergen. Patients had a baseline,
pre-treatment, exposure to ragweed pollen in the EEC for 3 hours on four
consecutive days and recorded nasal and non-nasal symptoms every 30 minutes.
These patients then received 4 weekly subcutaneous injections with either
Pollinex Quattro Ragweed (95 pts) or placebo (93 pts). After a period of
approximately three weeks to allow for the immune response, patients had a
second, post-treatment, series of exposures in the EEC.


Primary efficacy outcome has been assessed as the change from baseline in the
post-treatment total symptom scores ('TSS') in the Pollinex Quattro Ragweed
group compared with placebo in the per-protocol population of 177 patients. TSS
is a combination of all the major nasal (rhinorrhea, congestion, sneezing and
itchiness) and non nasal (itchy/gritty eyes, tearing/watery eyes, red/burning
eyes, ear/palate itching) allergy symptoms. Secondary outcomes include the
assessment of immune response.


Assessment of primary efficacy outcome indicated that total symptom score at
baseline was comparable between treatment groups. Re-assessment following the 4
injection treatment course indicated that in the Pollinex Quattro Ragweed
treatment group TSS had fallen from 15.7 to 9.1. This change from baseline in
the active treatment group was statistically significant (p<0.01) compared with
placebo and demonstrates a clinically significant 42% improvement in symptoms
and a relative superiority over placebo of 48%. Analysis of the Intention To
Treat population was of comparable magnitude and also statistically significant.


This clinical improvement was supported by immunological changes demonstrating a
statistically significant six-fold post-treatment rise in total ragweed specific
IgG (p<0.001 compared with placebo). These antibodies are thought to be an
important of component of the immunological processes which allow vaccination to
modifying the underlying disease process as well as treat symptoms.


There were no serious adverse experiences or severe systemic reactions reported
during the study. The incidence and nature of adverse experiences were as
expected with a subcutaneous vaccine. The commonest reported adverse experiences
were injection site reactions, however, the majority of adverse experiences were
mild.


Analysis of additional secondary outcome measures is currently ongoing


About Allergy Therapeutics' clinical trials programme


To complement today's announcement, Allergy Therapeutics is also providing an
update on its clinical trial programmes. There are three programmes of
subcutaneous immunotherapy in clinical development. These are the Pollinex
Quattro Grass, Tree & Ragweed programmes all of which are based on proprietary
MPL technology. Since 2005, 11 pre-Phase III studies have been conducted in
North America involving a total of approximately 700 patients and preparations
for initiating all three Phase III developments later this year are well
underway. Collectively these form the "Caution: Allergen" programme. In addition
there is a sub-lingual trial programme currently at phase I/II.


Grass Allergy Programme


The Grass pre-Phase III programme has completed four studies, one of which
(G203) recently reported results. Finalised data from the programme will be
submitted to FDA in Q2 2006. Subject to agreement with the FDA a single,
pivotal, international Phase III study in approximately 90 centres in North
America and Europe will be initiated with treatment scheduled for Q4 2006.


Tree Allergy Programme


The Pollinex Quattro Tree programme has completed three studies with analysis of
a fourth study currently ongoing. Subject to Phase III approval, treatment is
scheduled to start during the second half of 2006 with symptom assessment during
the 2007 season.


Ragweed Programme


R204 is pivotal for the registration of Pollinex Quattro in Canada. The Company
is currently working on completion of the analysis of R204 and compiling a
dossier for regulatory submission to Health Canada in mid-2006.


This study is also an important part of the global registration strategy and
compliments study R203, a dose-ranging study which is currently ongoing. These
data will inform the assumptions and final design of the ragweed Phase III
study. It is our intention, subject to Phase III approval, to initiate Phase III
during 2006 with patient treatment and assessment focussed on 2007 season.


Study R205, in a set-up phase, is designed to investigate the maintenance of
clinical benefit in those patients who participated in R204. Maintenance of
effect from year to year is crucial indicator of immune modulation that
differentiates allergy vaccines from symptomatic therapies.


Sublingual Programme


The Company has commenced a Phase IIa clinical Proof of Concept study
investigating the potential immunological and clinical benefits of MPL in
sublingual immunotherapy. The first phase of this study has completed
recruitment and sublingual treatment including MPL for the first time is
currently underway. Initial results are scheduled around the middle of the year
and, if successful, could represent a major therapeutic breakthrough in
immunotherapy



About MPL and M.A.T.A.


MPL (Monophosphoryl Lipid A) is an immunostimulatory substance used to enhance
the performance of vaccines (an "adjuvant"). It has been widely tested and can
be characterized as a Toll-Like 4 Receptor (TLR4) agonist. Allergy Therapeutics
is conducting a programme of late phase trials in injected vaccines (Pollinex
Quattro) with MPL and GSK has several vaccine candidates containing the adjuvant
including Fendrix(R), a vaccine for Hepatitis B which was approved by the EMEA
(the EU-wide medicines evaluation agency) last year.


M.A.T.A .stands for Modified Allergen Tyrosine Absorbate, other key components
of the product, which enhance both safety and efficacy of the vaccine and enable
this ultra short treatment regimen.



About Allergy Therapeutics plc


Allergy Therapeutics plc is a London Stock Exchange (AIM: AGY) listed specialist
pharmaceutical company focused on allergy vaccination. It has a profitable core
business achieving sales of allergy vaccines of over £22 million through its own
sales and marketing infrastructure


Allergy Therapeutics manufactures its own vaccine products in a MHRA approved,
sterile manufacturing facility in Worthing, United Kingdom. In January 2006 the
Company successfully underwent an audit by the MHRA.


Allergy Therapeutics has certain exclusive intellectual property rights to the
use of MPL in both injected and sublingual vaccines



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