Stemline Therapeutics Announces Multiple Preclinical Presentations Highlighting Its Pipeline of IL-3R-Directed Therapeutics at the American Society of Hematology (ASH) Annual Meeting

NEW YORK, Dec. 5, 2014 (GLOBE NEWSWIRE) -- Stemline Therapeutics, Inc. (Nasdaq:STML), announced today that results from multiple ongoing preclinical studies were selected for presentation at the 2014 American Society of Hematology (ASH) Annual Meeting, to be held December 6-9, 2014 at the Moscone Center, San Francisco, CA. Investigators will present data on Stemline's portfolio of therapeutics that target the interleukin-3 receptor (IL-3R), which is overexpressed on tumor bulk and cancer stem cells (CSCs) of a wide variety of hematologic malignancies.

"We have validated IL-3R as a target in patients with various hematologic malignancies, including blastic plasmacytoid dendritic cell neoplasm (BPDCN) and acute myeloid leukemia (AML)," commented Eric K. Rowinsky, M.D., Chief Medical Officer and Head of Research and Development at Stemline. He added, "The IL-3R is overexpressed on both cancer stem cells and mature malignant cells relative to their nonmalignant counterparts, and is also present on nonmalignant plasmacytoid dendritic cells (pDCs), which stimulate the growth of hematologic malignancies, such as multiple myeloma. Stemline is developing a panoply of IL-3R-directed therapeutics, including SL-401, SL-501, and SL-101 to treat IL-3R-overexpressing cancers, as well as malignancies driven by pDCs. Furthermore, pDCs have been demonstrated to play a role in several autoimmune diseases, including systemic lupus erythematosus and scleroderma, and we are developing a foundation for evaluating Stemline's IL-3R directed therapies in patients with these autoimmune diseases."

Preclinical data on SL-401, SL-501, and SL-101 to be presented at the 2014 ASH meeting.

Stemline's most advanced candidate, SL-401, is a clinical stage therapeutic currently in two multicenter, open-label clinical trials. The first trial is actively enrolling patients with BPDCN and relapsed/refractory AML, whereas the second trial is open for AML patients in first complete remission (CR) following induction chemotherapy, but display evidence of minimal residual disease (MRD) in their bone marrow and remain at high risk for relapse. Stemline is also planning additional clinical trials in other IL-3R+ indications. At ASH, Arghya Ray, Ph.D., of the LeBow Institute for Myeloma Therapeutics and Jerome Lipper Myeloma Center at the Dana-Farber Cancer Institute, Boston, MA, will present several lines of evidence demonstrating that SL-401 blocks pDC-triggered growth of myeloma cells, inhibits the development of osteoclasts responsible for bone resorption in myeloma patients, and limits the viability of CSC-like MM cells.

Janice Chen, Ph.D., of Stemline Therapeutics, will present preclinical data on SL-501, a next generation, 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. Dr. Chen's presentation will highlight the antitumor activity of SL-501 against Hodgkin's and non-Hodgkin's lymphoma.

Additionally, Lina Han, Ph.D., of the Department of Leukemia, Section of Molecular Hematology and Therapy, The University of Texas MD Andersen Cancer Center, Houston, TX, will present the results of preclinical studies detailing the activity of SL-101 in AML, as well as its mechanisms of action. SL-101, a next generation IL-3R targeted therapy, is a novel antibody-drug conjugate that targets the alpha chain of IL-3R (CD123). SL-101 has demonstrated preclinical activity against a variety of cancer types. Additional accepted abstracts include results from studies demonstrating IL-3R expression on certain myeloproliferative disorders and SL-401 activity against hairy cell leukemia.

Details on the presentations are as follows:

SL-401, a Novel Targeted Therapy Directed to the Interleukin-3 Receptor (IL-3R), Blocks Plasmacytoid Dendritic Cell (pDC)-Triggered Myeloma Cell Growth and Prevents Osteoclastogenesis
Lead Author: Arghya Ray, Ph.D., The LeBow Institute for Myeloma Therapeutics and Jerome Lipper Myeloma Center, Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA
Abstract Number: 3441
Date and Time: Sunday, December 7, 2014 at 6:00-8:00 PM PT
Location: West Building, Level 1 (Moscone Center)

SL-501, a Next-Generation Targeted Therapy Directed to the IL-3 Receptor (IL-3R), Possesses Preclinical Anti-Tumor Activity Against Hodgkin's and Non-Hodgkin's Lymphoma
Lead Author: Janice Chen, Ph.D., Stemline Therapeutics, New York, NY
Abstract Number: 4500
Date and Time: Monday, December 8, 2014 at 6:00-8:00 PM PT
Location: West Building, Level 1 (Moscone Center)

Anti-Leukemia Efficacy and Mechanisms of Action of SL-101, a Novel Anti-CD123 Antibody-Conjugate in Acute Myeloid Leukemia
Lead Author: Lina Han, Ph.D., Department of Leukemia, Section of Molecular Hematology and Therapy, The University of Texas MD Andersen Cancer Center, Houston, TX
Abstract Number: 981
Date and Time: Saturday, December 6, 2014 at 5:30-7:30 PM PT
Location: North Building, Hall E (Moscone Center)

Expression of CD123 (IL-3R-alpha), a Therapeutic Target of SL-401, on Myeloproliferative Neoplasms
Lead Author: Terra Lasho, Ph.D., Division of Hematology, Mayo Clinic, Rochester, MN
Abstract Number: 71457
Published online through ASH abstracts site

SL-401, a Targeted Therapy Directed to the Interleukin-3 Receptor (IL-3R), Shows Cytotoxic Activity Against Hairy Cell Leukemia
Lead Author: Christopher Brooks, Ph.D., Stemline Therapeutics, New York, NY
Abstract Number: 5663
Published online through ASH abstracts site

A copy of the above referenced abstracts can be viewed online through the ASH website at www.hematology.org.

About Stemline Therapeutics

Stemline Therapeutics, Inc. is a clinical stage biopharmaceutical company developing novel therapeutics that target both cancer stem cells (CSCs) and tumor bulk. Stemline is currently developing two clinical stage product candidates, SL-401 and SL-701. SL-401 is a targeted therapy directed to the interleukin-3 receptor (IL-3R). A multicenter clinical trial with SL-401 is currently open and accruing patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN) and advanced acute myeloid leukemia (AML). An additional clinical trial with SL-401 is currently open in patients with AML who are in first complete remission (CR) with minimal residual disease (MRD), which is associated with a high relapse rate. Stemline is also planning SL-401 trials in additional hematologic cancers including several uncommon, stem cell-derived myeloproliferative disorders. Previously, SL-401 demonstrated single-agent activity, including multiple durable CRs, in a Phase 1/2 trial in several indications including BPDCN and relapsed/refractory AML. SL-701 is an enhanced immunotherapy designed to activate the immune system to attack tumors. A multicenter clinical trial with SL-701 is currently open and accruing adult patients with glioblastoma multiforme (GBM) in first recurrence. Previously, an earlier version of the therapy demonstrated clinical activity, including durable CRs and partial responses (PRs), in Phase 1/2 trials in adults and children with advanced brain cancers. For more information about Stemline Therapeutics, visit www.stemline.com.

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 include: the success and timing of our preclinical studies and clinical trials, including site initiation, internal review board approval, scientific review committee approval, and patient accrual; our plans to develop and commercialize our product candidates; our available cash; our ability to obtain and maintain intellectual property protection for our product candidates; the ability of our product candidates to successfully perform in clinical trials; our ability to manufacture; the performance of third-party manufacturers, clinical research organizations, clinical trial sponsors and clinical trial investigators; and other risk factors 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 Eleventh Floor New York, NY 10022 Tel: 646-502-2307 Email: investorrelations@stemline.com

Source:Stemline Therapeutics, Inc.