Antisoma's AS1411 gains US and EU Orphan Drug Status for acute myeloid leukaemia

Antisoma's AS1411 gains US and EU Orphan Drug Status for acute myeloid leukaemia

London, UK, and Cambridge, MA: 13 October 2009 - Antisoma plc (LSE: ASM; USOTC: ATSMY) announces that its aptamer drug 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.

Positive phase II data for AS1411 in AML were presented at the 2008 ASH and 2009 ASCO meetings. Addition of AS1411 to high-dose cytarabine increased response rates without significantly increasing side-effects in patients with relapsed or refractory AML. Phase IIb trials are now planned: the first is expected to start in early 2010. Should this yield positive findings, rapid progress into a registration trial is anticipated.

AS1411 already has orphan drug status in both the US and the EU for the treatment of renal cancer. A phase II trial in renal cancer is ongoing, and expected to report initial data before the end of this year.

Glyn Edwards, Antisoma's CEO, said: "Gaining orphan drug status in AML further strengthens the exclusivity position of AS1411 in a setting where we have positive phase II data. This is an exciting time for AS1411, with phase II data in renal cancer coming soon and our investigation of the compound in AML progressing to the next stage."


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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 AML (acute myeloid leukaemia)
AML is a type of cancer in which the bone marrow makes abnormal and immature blood cells, eventually leading to bone marrow failure. The American Cancer Society estimates that there will be over 13,000 new cases of AML diagnosed this year in the US alone.

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.

About orphan drug status
The US Orphan Drug Act and European Orphan legislation are designed to stimulate the development of drugs for conditions affecting fewer than a defined number of patients by providing additional incentives to developers of such drugs. One of the most valuable of these incentives is a period of market exclusivity. In the US, orphan drug status confers a seven-year period of exclusivity after approval in the given indication. In the EU, a ten-year period of exclusivity is provided. Other incentives include regulatory guidance from the competent authority, fee reductions and, in the US, tax credits.

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. Please visit for further information about Antisoma.