MultiStem: Additional Phase I data

Additional data from an open-label, dose-escalation Phase I trial in 36 patients showed that a single injection of the highest dose of IV MultiStem given following allogeneic hematopoietic stem cell transplant (HSCT) led to a 100-day cumulative incidence of moderate to severe acute GvHD of 11%, which Athersys said "compares favorably" with historical clinical experience for this patient population (40-60% incidence rate for grade II-IV GvHD for historical control). No patient developed severe GvHD and there were no graft failures over the 100-day period following HSCT. Furthermore, relapse-free survival at 100 days was 81% for MultiStem vs. 65-70% for historical clinical experience. All patients experienced successful neutrophil engraftment and 86% of patients experienced successful platelet engraftment. Median time to neutrophil and platelet engraftment was 15 and 16 days, respectively. MultiStem was well tolerated as both single and multiple infusions.

The trial, which enrolled patients with acute leukemia, chronic myelogenous leukemia (CML) or myelodysplastic syndrome (MDS), evaluated a single dose of 1, 5 and 10 million cells/kg of body weight IV MultiStem given 2 days after HSCT; multiple doses of 1 or 5 million cells/kg of body weight IV MultiStem given on days 2, 9 and 16 after HSCT; and multiple doses of 5 million cells/kg of body weight IV MultiStem given on days 2, 9, 16, 23 and 30 after HSCT. Data were presented at the BMT Tandem Meetings in San Diego. Last May, Athersys reported interim data from 18 patients showing that all doses of MultiStem in the single infusion arm were well tolerated with no dose-limiting toxicities (DLTs) (see BioCentury, June 6, 2011). Athersys said it plans to meet with FDA to discuss plans for the next phase of clinical development for MultiStem, which could include a Phase II/III trial. ...