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 10mg/kg/day AS1411 plus cytarabine or cytarabine alone. The addition of AS1411 at this dose to cytarabine was well tolerated.
Patients are now being enrolled into the second (‘higher dose’) stage of the trial, which compares 40mg/kg/day AS1411 plus cytarabine with cytarabine alone.
Activity data currently available from 16 patients showed that 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. Out of two of the first five patients crossed over, one of them showed a 90% reduction in leukaemic blast count after treatment with the combination.
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.”