PRESS RELEASE: Antisoma Shares Slide as Novartis Corporation (NVS) Sets up Avastin Fight

Antisoma Shares Slide as Novartis Corporation Sets up Avastin Fight

LONDON--Nov 20, 2007 -- ASA404 phase III lung cancer trial to include broader range of patients London, UK: 20 November 2007 - Cancer drug developer Antisoma holds its AGM today. At the meeting, CEO Glyn Edwards will provide an update on the Company's key pipeline products and other corporate developments:

"We are making significant advances across our pipeline, and expect to achieve further important milestones during 2008.

ASA404 - update on plans for phase III trial in lung cancer

Our licensing partner, Novartis, plans to start a pivotal phase III trial of ASA404 in non-small cell lung cancer (NSCLC) in early 2008. This trial will now include patients with both major types of NSCLC: squamous and non-squamous. Previous guidance was that the pivotal study would be limited to patients with squamous disease. Discussions with regulatory authorities regarding the trial design are ongoing.

Because more patients are diagnosed with non-squamous than squamous NSCLC, this change more than doubles the population of NSCLC patients addressed directly by the phase III trial. Eligibility for the phase III trial will now be similar to that in our phase II studies, where we showed a substantial survival benefit with ASA404 in a broad population of NSCLC patients.

If the phase III trial is successful, applications to market ASA404 for NSCLC will be filed in 2010 or 2011. The drug also has potential in other cancers. These include prostate cancer, where Antisoma has reported encouraging interim data from a phase II trial and expects to report survival findings next year.

AS1411 - AML phase II trial underway, other trials planned

Our randomised phase II trial of AS1411 in AML (acute myeloid leukaemia) is on track to report initial data in the first half of next year.

The trial compares patients receiving the current standard therapy, cytarabine, with patients receiving cytarabine plus AS1411. We are evaluating two different doses of AS1411, 10 and 40 mg/kg/day. The first report will compare 10 mg/kg/day AS1411 plus cytarabine with cytarabine alone. The primary endpoint is the proportion of patients achieving a complete response (disappearance of leukaemia cells) after treatment.

We are also planning to conduct a phase II trial in renal cancer, an indication where there was promising evidence of anti-cancer activity in phase I. The phase II trial will not now start in the first half of 2008, as previously expected, because we intend to complete additional preclinical and toxicology work before finalising our plans. This aims to identify a safe and optimal approach to repeat dosing of AS1411 for use in the renal cancer trial and other programmes where repeat dosing may be desirable. In parallel with this work, we are making plans for a trial in a third cancer indication, and expect to announce details early next year.

AS1402 and AS1409 - on track with development plans

AS1402 is on track to enter a randomised phase II trial in breast cancer during 2008. Similarly, we expect to meet our objective of initiating our phase I trial of AS1409 before the end of 2007.

United States operation established in Princeton

We have opened an office in Princeton, New Jersey, in order to support our US clinical and regulatory activities. The new office is headed by Dr Chris Smyth, Head of Clinical Operations, who was formerly based at our London office. A number of new, experienced staff have been recruited to meet the needs of our growing clinical trials programme in the US.

Positive outlook

Our pipeline continues to advance, with ASA404 poised to enter phase III and the first phase II data on AS1411 expected soon. By the end of 2007, we expect to have four drugs in clinical trials, and our plans to bring in further drugs for development are progressing well. With last-reported cash of over £60 million and a strong operational base, we are well placed both to maximise the value of our existing assets and to continue the growth of our business."

Enquiries:

Glyn Edwards, CEO Daniel Elger, Director of Communications +44 (0)20 8799 8200 Antisoma plc

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

Brian Korb +1 646 378 2923 The Trout Group

This Interim Management Statement is published in accordance with the UK Listing Authority's Disclosure and Transparency Rules, in respect of the period from 30 June 2007 to 20 November 2007.

Except for the historical information presented, 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 product discovery and development, including statements regarding the company's clinical development programmes, the expected timing of clinical trials and regulatory filings. Such statements are based on management's current expectations, but actual results may differ materially.

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.co.uk for further information about Antisoma.