Antisoma to advance AS1411 in AML based on positive phase II data
presented at ASCO
London, UK, Cambridge, MA, and Orlando, FL: 29 May 2009 - Antisoma
plc (LSE: ASM; USOTC: ATSMY) announces that it plans to advance the
development of AS1411 in AML (acute myeloid leukaemia) based on
positive data from a phase II study in relapsed and refractory AML
presented today at the American Society of Clinical Oncology (ASCO)
meeting in Orlando.
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. The AS1411 phase II study in AML was the first
randomised controlled trial to test an aptamer as a treatment for
cancer.
A broad spectrum of AML patients were allowed to participate in the
trial, but all had disease that had proved non-responsive
(refractory) to prior treatments or had relapsed after one or more
previous therapies. Given these requirements, many of the patients
had a very poor prognosis.
Patients were assigned randomly to three treatment groups. A control
group was treated with high-dose cytarabine, a standard chemotherapy
treatment for relapsed and refractory AML. The other two groups
received high-dose cytarabine combined with either 10 or 40 mg/kg/day
AS1411.
The response rate in the cytarabine control group was 5% (1/19)
patients. By contrast, response rates in the groups receiving 10 or
40 mg/kg/day AS1411 with cytarabine were 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. Most of the side-effects observed were
those typically associated with cytarabine treatment.
Commenting on the findings, Dr Robert Stuart of the Medical
University of South Carolina, Principal Investigator in the phase II
trial and presenter of the data at the ASCO meeting, said: "These
findings, seen in a very poor prognosis group of leukaemia patients,
are very promising, and encourage us to go forward and further define
the potential for AS1411 as a new treatment option for patients with
AML."
Glyn Edwards, Antisoma's CEO added: "With these positive results, we
have a good basis on which to progress AS1411 in AML. We are working
with leading experts in the field to identify the best approach to
further development and ensure we make the most of this exciting
opportunity."
It is anticipated that Antisoma will carry out a programme of phase
IIb trials to optimise the choice of patient population and design
for future pivotal studies of AS1411 in AML.
A separate phase II trial of AS1411 in renal cancer recently
completed patient recruitment and is expected to report initial data
later this year.
A copy of the poster presented at the ASCO meeting is available on
the Antisoma website at www.antisoma.com/asm/products/as1411
Enquiries:
Antisoma plc:
Glyn Edwards, CEO
Daniel Elger, VP Marketing & Communications
(In Orlando) +44 (0) 7909 915 068
Mark Court/Lisa Baderoon/Rebecca Skye +44 (0)20 7466 5000
Dietrich
Buchanan Communications
Brian Korb +1 646 378 2923
The Trout Group
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 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 belongs to a new type of drugs called aptamers. These are
short pieces of DNA or RNA that fold into three-dimensional
structures capable of targeting particular proteins. AS1411 is a DNA
aptamer that binds to nucleolin, a protein expressed in the nucleus
of all cells but which in cancer cells is also exposed on the cell
surface, providing a basis for specific targeting by AS1411. When
AS1411 binds to nucleolin on cancer cells, it is internalised and
causes apoptosis through interference with various functions of
nucleolin.
A 30-patient phase I trial provided evidence for activity of AS1411
monotherapy. Among 12 patients with renal cancer, two showed
objective responses and nine had a best overall response of stable
disease. No serious adverse events related to treatment were
observed.
Two phase II trials have been conducted with AS1411: the AML study
described here and a study in renal cancer, which is ongoing.
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 www.antisoma.com
for further information about Antisoma.
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