Antisoma PLC ASH Meeting Update

LONDON and CAMBRIDGE, MA--(Marketwire - December 02, 2010) - Antisoma plc (LSE: ASM; USOTC: ATSMY) today provides an update on its blood cancer programmes and announces details of a presentation at the American Society of Hematology (ASH) Annual Meeting.

AS1413 phase III data in secondary AML expected Q1 2011

Antisoma announced this week that it expects results from the ACCEDE phase III trial of AS1413 in secondary acute myeloid leukaemia (secondary AML) during the first quarter of 2011.

Secondary AML represents a significant fraction of AML cases. This form of the disease evolves from myelodysplastic syndrome (MDS) or results from chemotherapy or radiotherapy treatment for other cancers. Patients respond particularly poorly to current AML therapies.

Antisoma’s ACCEDE trial compares a novel regimen of AS1413 plus cytarabine with a standard regimen of daunorubicin and cytarabine. Enrolment of over 420 patients was completed in September. If the trial yields positive data, Antisoma plans to file for marketing authorisations.

ASH presentation on secondary AML

A new analysis, to be presented on Sunday at the American Society of Hematology (ASH) Annual Meeting in Orlando, FL, will highlight the adverse risk factors associated with secondary AML and determinants of prognosis within this patient group.

Dr Mikkael Sekeres and collaborators from the Cleveland Clinic analysed a combined data-set of 165 secondary AML patients, including patients treated at their own hospital and participants in the phase II trial of AS1413. Being male, over 60 or having adverse cytogenetics were factors particularly associated with a poor prognosis. The abstract can be found on the ASH website at www.hematology.org (abstract no 2139); once presented, the poster will be available at www.antisoma.com

AS1411 phase IIb trial in AML progressing

As well as AS1413, Antisoma is evaluating its DNA aptamer, AS1411, as a potential treatment for leukaemias. A phase IIb trial combines AS1411 with high- dose cytarabine chemotherapy in patients with relapsed or refractory AML. The trial builds on positive data from an earlier trial in similar patients. Headline findings are expected in the first half of 2011.

Except for the historical information presented, certain matters discussed in this announcement 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.

About AS1413 (amonafide L-malate)

AS1413 (amonafide L-malate) was added to Antisoma’s pipeline through the acquisition of Xanthus Pharmaceuticals, Inc. in June 2008. AS1413 is a novel DNA intercalator that induces apoptotic signalling by blocking topoisomerase II binding to DNA. This differs from the action of classical topoisomerase II inhibitors, which induce apoptosis by causing extensive DNA damage. A further distinctive feature of AS1413 is its ability to evade Pgp and related transporters responsible for multi-drug resistance (MDR).

A pivotal phase III trial (ACCEDE) is evaluating AS1413 as a treatment for secondary AML, a condition often associated with MDR and in which outcomes with currently available treatments are poor. An earlier phase II trial showed a complete remission rate of 39% in patients with secondary AML, a finding that compares favourably with data from two previous co-operative group studies in which similar patients were treated with standard anthracycline plus cytarabine regimens. AS1413 has FDA fast-track designation and orphan drug status for the treatment of AML in both the US and the EU.

About AS1411

AS1411 belongs to a new type of drug called aptamers. These drugs are short pieces of DNA or RNA that fold into three-dimensional structures capable of targeting particular proteins. AS1411 is a DNA aptamer that targets nucleolin, a protein found on the surface of cancer cells. AS1411 was originally developed by Dr Paula Bates, Dr John Trent and Prof. Donald Miller at the University of Alabama and then at the University of Louisville. Antisoma added AS1411 to its pipeline when it acquired the Louisville-based company Aptamera Inc. in 2005. A phase II trial reported higher remission rates and a lack of any significant additional toxicity when AS1411 was added to high-dose cytarabine chemotherapy as a treatment for relapsed or refractory AML. A phase IIb trial is now further evaluating AS1411 in similar patients. AS1411 has orphan drug status for the treatment of AML in both the US and the EU.

Background on Antisoma

Antisoma is a London Stock Exchange-listed biopharmaceutical company that develops novel products for the treatment of cancer. The Company has operations in the UK and the US. Please visit www.antisoma.com for further information about Antisoma.

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Source: Antisoma plc via Thomson Reuters ONE