Antisoma initiates phase IIb trial of AS1411 in acute myeloid leukaemia

Antisoma initiates phase IIb trial of AS1411 in acute myeloid leukaemia

London, UK, and Cambridge, MA: 18 March 2010 - Antisoma plc (LSE: ASM; USOTC: ATSMY) announces that it has started a randomised, controlled, multi-territory, phase IIb trial of AS1411 in patients with acute myeloid leukaemia (AML).

Dr Ursula Ney, Chief Operating Officer of Antisoma, said: "AML is a devastating disease for which new treatment options are desperately needed. This phase IIb trial builds on earlier positive phase II findings, and is designed to pave the way for a registration trial of AS1411 in AML."

The phase IIb trial is enrolling patients with AML in first relapse or refractory to one prior treatment. Around 90 patients are being randomised to three treatment groups. A control group is receiving high-dose cytarabine, a standard chemotherapy treatment for this patient population. The other two groups are receiving high-dose cytarabine combined with AS1411 at 40 or 80 mg/kg/day. The trial will compare the three treatment groups with respect to safety, response rates, period free of leukaemia and survival. Data are expected next year.

The phase IIb trial follows a randomised phase II trial in AML, which reported positive results at the 2009 Annual Meeting of the American Society of Clinical Oncology (ASCO).


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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 Group'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 the AS1411 trials in AML
The phase IIb trial of AS1411 builds on data from an earlier phase II study reported at ASCO 2009. It evaluates a higher maximum dose of AS1411 (80 vs 40 mg/kg/day), uses a higher dose of cytarabine (4 vs 3 g/day) and is testing the drug in a refined patient population (patients in first relapse or refractory to one prior treatment vs all relapsed or refractory patients). The new trial is intended to identify the optimal dose of AS1411 for a pivotal AML trial and to provide a more detailed assessment of the benefit that could be achieved by adding AS1411 to standard chemotherapy in this setting. This is important in determining the number of patients to be included in a phase III registration trial and the design of such a study.

In the earlier phase II trial, patients were randomised to one of three treatment groups: high-dose cytarabine, high-dose cytarabine plus 10 mg/kg/day AS1411 or high-dose cytarabine plus 40 mg/kg/day AS1411. Response rates in the three treatment groups were 5% (1/19 patients), 21% (4/19 patients) and 19% (4/21 patients), respectively. Addition of AS1411 to high-dose cytarabine was well tolerated at both the 10 and 40 mg/kg/day doses, with most side-effects observed being those typically associated with cytarabine treatment.

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.

AS1411 has been granted orphan drug status in both the United States and the European Union for the treatment of acute myeloid leukaemia (AML). The grants will provide seven years of market exclusivity in the US and ten years of exclusivity in the EU if AS1411 is approved for use in AML.

About 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. It has two drugs in phase III trials: ASA404, a tumour-vascular disrupting agent, which is partnered with Novartis and which is under development for lung and breast cancers; and AS1413, a novel DNA intercalator being evaluated in secondary AML. Please visit for further information about Antisoma.