Stemline to feature SL-401 clinical efficacy at ASH Annual Meeting

Stemline Therapeutics, Inc. today announced that two abstracts featuring SL-401 clinical efficacy in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), and pre-clinical activity in chronic myeloid leukemia (CML) have been selected for presentation at the upcoming 52nd Annual Meeting of the American Society of Hematology (ASH) to be held in Orlando, FL from December 4-7, 2010. The posters will be presented by Stemline's collaborators at MD Anderson Cancer Center.

The clinical results with SL-401 demonstrate efficacy, including two durable complete remissions (CRs), multiple blast reductions and disease stabilizations in relapsed/refractory AML, poor risk elderly AML, and high risk MDS. Importantly, an overall survival benefit was also seen in heavily pre-treated AML patients, a very difficult to treat population and an unmet medical need. Results also include preliminary signals of a clinical anti-CSC effect that further supports the importance of targeting CSCs in patients. SL-401 was safe, well-tolerated, and uniquely bone marrow-sparing. In addition, the pre-clinical studies demonstrate SL-401 activity against CML blasts and CSCs from patients who are resistant to tyrosine kinase inhibitors (TKIs).

SL-401 is a novel CSC-directed compound that targets the interleukin-3 receptor (IL-3R). IL-3R is over-expressed on AML CSCs relative to normal hematopoietic stem cells. IL-3R is also over-expressed on AML blasts as well as on multiple other hematological malignancies including MDS, CML, Hodgkin's disease, and certain non-Hodgkin's lymphomas. SL-401 is currently in ongoing Phase I/II trials of patients with poor risk elderly AML, high risk MDS, and CML who are not candidates for TKI therapy. In addition, given the promising clinical results in relapsed/refractory AML, SL-401 is also now poised for later stage Phase II/III trials in this indication. Details on the abstracts selected for presentation are as follows: