Positive data on Antisoma's ASA404 presented at ASCO

LONDON, UK, Jun 01 (MARKET WIRE) --

London, UK, and Chicago, IL, 1 June 2008 - Antisoma (LSE: ASM; USOTC:ATSMY)
announces that two presentations supporting ASA404 are being made at this
year's American Society of Clinical Oncology (ASCO) meeting in Chicago. ASA404
is
a Tumour-Vascular Disrupting Agent for which worldwide rights were licensed to
Novartis in April 2007.

Broad potential in lung cancer

A poster presentation to be given today shows that patients with both
squamous
and non-squamous types of non-small cell lung cancer experienced a survival
benefit in phase II trials with ASA404. Addition of ASA404 to chemotherapy was
generally well tolerated in both groups, with no evidence for bleeding
related side-effects that have been seen with some other drugs in squamous
patients. Around 30% of patients with non-small cell lung cancer have
squamous disease.

The ASCO presentation is a retrospective analysis of data from phase II
trials
in which ASA404 was added to carboplatin and paclitaxel chemotherapy. Patients
who
received two different doses of ASA404 with their chemotherapy were pooled and
compared with patients who received chemotherapy alone. Median survival data
showed an extension of 4.7 months in squamous patients (10.2 vs 5.5 months) and
of
3.9months in non-squamous patients (14.9 vs 11.0 months). Response rates and
time
to tumour progression were also superior in both groups with ASA404.

The data will be presented by Dr Mark McKeage of the Auckland Cancer Centre,
New
Zealand, a leading investigator in phase II trials of ASA404 who is now
participating in Novartis' ATTRACT-1 phase III trial of ASA404 in non-small
cell lung cancer. Dr McKeage said "These data suggest that ASA404 could provide
benefits for a wide range of lung cancer patients and support the broad
inclusion criteria of the phase III ATTRACT-1 study."

The ATTRACT-1 phase III trial started in April 2008 and includes both
squamous
and non-squamous patients. Patients are being randomised to receive
carboplatin and paclitaxel plus either ASA404 or a placebo. The primary endpoint
in the trial is overall survival, and key secondary endpoints are overall
survival in the squamous and non-squamous subgroups. If the ATTRACT-1 trial
yields positive results, it is expected that filings for marketing
authorisations will take place
in 2011.

Glyn Edwards, CEO of Antisoma, added: "The phase II trial data in lung
cancer have provided remarkably consistent support for ASA404 across different
measures of efficacy, with different doses, and now in patients with
different types of the disease."

The poster presentation will be available from 8pm today UK time (2pm
Chicago
time) on Antisoma's website (www.antisoma.com).

Supportive interim data in prostate cancer

An oral presentation on ASA404 will be given tomorrow in the Clinical
Science
Symposium 'Novel anti-angiogenic mechanisms' by Prof Roberto Pili of Johns
Hopkins University. This presentation will include details of interim findings
from the phase II trial of ASA404 in prostate cancer, which were announced
in headline form in October, as well as a new analysis of ASA404's effects
on the prostate cancer biomarker PSA.

In the prostate cancer trial, patients were randomised to receive either
1200
mg/m2 ASA404 plus docetaxel or docetaxel alone. Several different measures now
suggest better results with the ASA404-docetaxel combination than with
docetaxel alone:

* PSA response rates were 59% with ASA404 plus docetaxel and 37% with
docetaxel alone. A new analysis considers the proportion of patients
showing a 30% decline in PSA levels in the 3 months after the start of
treatment. This was the PSA measure most predictive of survival in a major
prostate cancer study. Proportions of patients with such a PSA decline were
63% with ASA404 plus docetaxel and 47% with docetaxel alone

* Tumour response rates in patients assessable by RECIST were 23% in
patients who received ASA404 plus docetaxel versus 9% in patients who
received docetaxel alone

* Time to disease progression was 7.3 months in patients who received
ASA404 plus docetaxel and 6.9 months in patients who received docetaxel
alone, according to investigators' assessment; an independent assessment
showed a
similar pattern (8.7 vs 8.4 months)

* Safety findings from the trial showed that addition of ASA404 to
chemotherapy was generally well tolerated.

Overall, interim findings from the trial are encouraging. A decision on next
steps
in prostate cancer will be made once median survival data are available. These
are
expected during the second half of this year.

Prof Pili's presentation will be available from 5.30pm UK time tomorrow
(11.30am Chicago time) on Antisoma's website at
www.antisoma.com.

Enquiries:
Glyn Edwards, CEO
Daniel Elger, Director of Communications +44 (0)7909 915
Antisoma plc 068

Mark Court/Lisa Baderoon/Rebecca Skye +44 (0)20 7466
Dietrich 5000
Buchanan Communications

Brian Korb +1 646 378 2923
The Trout Group

Certain matters discussed in this statement are forward looking statements
that are subject to a number of risks and uncertainties that could cause actual
results
to differ materially from results, performance or achievements expressed or
implied by such statements. These risks and uncertainties may be associated with
productdiscovery and development or licensing activities, including statements
regarding
the clinical development programmes, the expected timing of clinical trials
and regulatory filings, out-licensing opportunities, and funding requirements.
Such
statements are based on management's current expectations, but actual results
may differ materially.

Notes for Editors:

PSA and PSA responses

PSA is a protein, prostate-specific antigen. Levels of PSA in the blood are
used in the diagnosis of prostate cancer and the tracking of responses to its
treatment. PSA is one of the most widely recognised disease markers in oncology.
In the ASA404 phase II trial, PSA response was defined as a 50% or greater
reduction in PSA level from baseline. This is in accordance with the Bubley
criteria(Eligibility and response guidelines for phase II clinical trials in
androgen-independent prostate cancer: recommendations from the
Prostate-Specific Antigen Working Group. Journal of Clinical Oncology 1999,
17:3461-3467).

Data supporting the importance of a 30% decline in PSA within three months
of
the start of treatment are reported in 'Prostate-Specific Antigen and Pain
Surrogacy
Analysis in Metastatic Hormone-Refractory Prostate Cancer'; Andrew J. Armstrong,
Elizabeth
Garrett-Mayer,Yi-Chun Ou Yang, Michael A. Carducci, Ian Tannock, Ronald de Wit,
and Mario
Eisenberger; Journal of Clinical Oncology 2007, 25:3965-3970.

RECIST

Tumour responses (reflecting the growth or shrinkage or tumours after
treatment) are often assessed according to RECIST (Response Evaluation Criteria
In
Solid Tumours). In prostate cancer, modified RECIST criteria are used because of
the need to assess bone metastases, which cannot be assessed using the
standard criteria.

Time to tumour/time to disease progression

Time to tumour progression is the time from the start of treatment (of a
solid
tumour) until disease progression is shown according to RECIST. As with the
evaluation of response, this assessment is modified in prostate cancer. In
the phase II ASA404 prostate cancer trial, investigators' assessment of time to
disease progression included RECIST data, PSA data and clinical observations.
Independentassessment of time to disease progression used RECIST and PSA data.

Background on ASA404

ASA404 (DMXAA) is a small-molecule Tumour-Vascular Disrupting Agent
(Tumour-VDA)
which targets the blood vessels that nourish tumours. The drug was discovered by
Professors Bruce Baguley and William Denny and their teams at the Auckland
Cancer Society Research Centre, University of Auckland, New Zealand. It was
in-licensed by Antisoma from Cancer Research Ventures Limited (now Cancer
ResearchTechnology), the development and commercialisation company of the Cancer
Research Campaign (now Cancer Research UK), in August 2001. Antisoma has
conducted a number of phase II trials, including a randomised trial in
non-small cell lung cancer. In this trial, patients who received ASA404 in
addition to chemotherapy had a median survival of 14.0 months while patients who
received chemotherapy alone had a median survival of 8.8 months. Additional
details of
phase II findings are available on Antisoma's website at www.antisoma.com.
Worldwide rights to ASA404 were licensed to Novartis AG in April 2007. A
phase III trial (ATTRACT-1) is evaluating ASA404 in combination with
carboplatin and paclitaxel in the first-line treatment of non-small cell
lung cancer.

Background on Antisoma

Headquartered in London, UK, Antisoma is a biopharmaceutical company that
develops novel products for the treatment of cancer. Antisoma fills its
development pipeline by acquiring promising new product candidates from
internationally recognised academic or cancer research institutions. Its core
activity is the preclinical and clinical development of these drug
candidates. Please visit www.antisoma.com for further information about
Antisoma.

Copyright Copyright Hugin AS 2008. All rights reserved.

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