Antisoma has presented positive data from an ongoing Phase II study of its AS1411 compound in relapsed and refractory acute myeloid leukaemia.

The firm said that complete data are now available from the first stage of the trial, in which patients were randomised 1:2 to receive high-dose cytarabine alone or high-dose cytarabine plus AS1411 at 10mg/kg/day. All patients entering the trial had relapsed or failed to respond to treatment, so few responses were expected.

Accordingly, there were no responses in the control group (0/9 patients), though by contrast, the response rate for AS1411 group was 16% (3/19 patients). Other findings came from a 'cross-over' element in the trial, under which three control group patients who failed to respond to cytarabine were given the opportunity to receive a further course of treatment with cytarabine plus AS1411. One of the three experienced a 90% reduction in leukaemia blast count after receiving the AS1411 regimen, the company said.

Enrollment has now been completed in the second stage of the trial, which has randomised around 30 more patients 1:2 to receive high-dose cytarabine or high-dose cytarabine plus AS1411 at 40mg/kg/day, a four-fold higher dose than the first stage. Final results are due in the first half of 2009.

Glyn Edwards, Antisoma's chief executive, said: "We have now seen evidence of activity with AS1411 in patients with hard-to-treat leukemia and advanced renal cancer. This supports non-clinical data suggesting that the drug has potential across a wide variety of blood and solid cancers”.