Stemline Therapeutics Announces Presentation of SL-501 Preclinical Efficacy Data in TKI-Resistant CML at the Annual Meeting of the American Association of Cancer Research (AACR)

NEW YORK, April 1, 2014 (GLOBE NEWSWIRE) -- Stemline Therapeutics, Inc. (Nasdaq:STML) announced today that data demonstrating SL-501 inhibits the growth of tyrosine kinase inhibitor (TKI) resistant chronic myeloid leukemia (CML) cells in preclinical models was selected for poster presentation at the Annual Meeting of the American Association for Cancer Research (AACR) Conference, being held April 5-9, 2014 in San Diego, CA. SL-501 is a highly potent targeted therapy directed to the interleukin-3 receptor (IL-3R). SL-501 is a next generation variant of SL-401; SL-401 is currently being advanced in clinical trials of multiple hematologic cancers.

The study assessed the activity of SL-501 against a panel of CML tumors in vitro and demonstrated that SL-501 was highly potent at killing both TKI-sensitive as well as TKI-resistance CML cells. In addition, the combination of SL-501 with the TKI imatinib (Gleevec®) demonstrated an enhanced anti-tumor effect versus TKI alone. SL-501 has also been shown to selectively kill CML cancer stem cells (CSCs) from CML patients whose disease was TKI resistant, as well as to significantly prolong overall survival of mice implanted with human TKI-resistant CML.

Eric K. Rowinsky, M.D., Chief Medical Officer and Head of Research and Development at Stemline Therapeutics, noted, "Although imatinib and other TKIs are quite effective in the initial treatment of CML, these therapies do fail, which is often accompanied by specific mutations that may ultimately render TKIs ineffective. These experiments show that our IL-3R targeting drugs, in particular SL-501, could help in the fight against TKI resistant CML."

About SL-401 and SL-501

SL-401 is a novel targeted therapy directed to the interleukin-3 receptor (IL-3R), a target present on tumor bulk and cancer stem cells (CSCs) of multiple hematologic cancer indications. SL-401 has demonstrated clinical activity in several indications, including acute myeloid leukemia (AML), blastic plasmacytoid dendritic cell neoplasm (BPDCN), and myelodysplastic syndrome (MDS), as well as preclinical activity in multiple myeloma (MM), chronic myeloid leukemia (CML), rare IL-3R+ cancers such as chronic eosinophilic leukemia, and certain lymphoid leukemias and lymphomas. SL-501 is a rationally designed variant of SL-401 that binds to IL-3R with high affinity and has shown enhanced potency against hematologic cancer cells in both in vitro and in vivo xenograft experiments.

Details on the presentation are as follows:

SL-501, a Next-Generation Targeted Therapy Directed to IL-3R, Inhibits the Growth of Tyrosine Kinase Inhibitor-Resistant CML Cells

Abstract #: 4507
Lead Author: Christopher Brooks, Ph.D., Stemline Therapeutics, Inc., New York, NY
Session: Biologic Therapy 3/Experimental and Molecular Therapeutics 31
Date and Time: Tuesday, Apr 08, 2014, 1:00 PM - 5:00 PM PT
Location: Hall A-E, Poster Section 29

About Stemline Therapeutics

Stemline Therapeutics, Inc. is a clinical-stage biopharmaceutical company developing novel oncology therapeutics that target both cancer stem cells (CSCs) and tumor bulk in a variety of cancer types. Stemline's clinical candidates, SL-401 and SL-701, have demonstrated clinical activity, including durable complete responses (CRs), in Phase 1/2 studies of patients with advanced hematologic and brain cancer, respectively. SL-401 is being advanced into later stage programs in blastic plasmacytoid dendritic cell neoplasm (BPDCN) and other rare malignancies, as well as additional hematologic cancers including acute myeloid leukemia (AML) and myeloma. SL-701 is being advanced into later stage trials of adults with glioblastoma multiforme (GBM) at first recurrence, and children with brainstem and non-brainstem glioma. For more information about Stemline Therapeutics, visit

Forward-Looking Statements

Some of the statements included in this press release may be forward-looking statements that involve a number of risks and uncertainties. For those statements, we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. The factors that could cause our actual results to differ materially are identified from time to time in our reports filed with the Securities and Exchange Commission. Any forward-looking statements set forth in this press release speak only as of the date of this press release. We do not intend to update any of these forward-looking statements to reflect events or circumstances that occur after the date hereof.

CONTACT: Investor Relations Stemline Therapeutics, Inc. 750 Lexington Avenue 11th Floor New York, NY 10022 Tel: 646-502-2307 Email: investorrelations@stemline.comSource:Stemline Therapeutics, Inc.