Early findings show promise as AS1411 AML study proceeds to higher-dose stage

07-07-2008

Cancer drug developer Antisoma plc (LSE: ASM; USOTC: ATSMY) today announces initial findings from its phase II trial of AS1411 in relapsed and refractory AML (acute myeloid leukaemia).

* Patient enrolment has been completed in the first ('lower dose')
stage of the trial, in which 33 patients were randomly assigned
to be treated with either 10 mg/kg/day AS1411 plus cytarabine or
cytarabine alone

* The addition of AS1411 at this dose to cytarabine was well
tolerated

* Activity data are currently available from 16 patients:

* Among 11 patients who received AS1411 plus cytarabine, one had
a complete response (CR) and one had a complete response with
incomplete recovery of platelet counts (CRP); a third patient
had a 'cytogenetic response' but had leukaemic blasts
remaining

* Among five patients who received cytarabine alone, none had a
CR, none had a CRP and there were no cytogenetic responses

* Patients who did not respond to cytarabine alone could be
'crossed over' to receive AS1411 plus cytarabine; two of the
first five patients crossed over, one of whom showed a 90%
reduction in leukaemic blast count after treatment with the
combination

Dr Robert Stuart of the Medical University of South Carolina, an investigator in the trial, said: "The initial findings from the AML phase II trial encourage us to treat more patients and in particular to test the potential of using a four-fold higher dose of AS1411 in this setting."

Patients are now being enrolled into the second ('higher dose') stage of the trial, which compares 40 mg/kg/day AS1411 plus cytarabine with cytarabine alone.

Glyn Edwards, Antisoma's CEO, added: "There is a great need for new treatments in AML, especially for patients with relapsed and refractory disease where response rates have historically been very poor. We are excited about the potential of AS1411 in this indication, and look forward to seeing more extensive data including that from patients receiving a higher dose of the drug."

Further data from the AML phase II trial will be submitted for presentation at forthcoming medical conferences. A second phase II trial of AS1411, in patients with renal cancer, is expected to start before the end of this year.

Contact::

Glyn Edwards, CEO

Daniel Elger, Director of Communications +44 (0)7909 915 068
Antisoma plc

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