Stemline Therapeutics Announces Five Presentations at the American Society of Hematology (ASH) Annual Meeting, Including a Clinical Update of SL-401 in BPDCN

NEW YORK, Nov. 14, 2013 (GLOBE NEWSWIRE) -- Stemline Therapeutics, Inc. (Nasdaq:STML) today announced five presentations at the 2013 American Society of Hematology (ASH) Annual Meeting and Exposition, to be held December 7-10, 2013, at the Ernest N. Morial Convention Center in New Orleans, LA. Investigators will present a clinical update of SL-401, a novel targeted therapy directed to tumor bulk and cancer stem cells (CSCs), in patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN), as well as preclinical data of SL-401 in additional indications including multiple myeloma and chronic eosinophilic leukemia, a rare hematologic cancer. In addition, preclinical data of SL-101, a novel antibody-drug conjugate (ADC) directed to tumor bulk and CSCs, in FLT3-ITD acute myeloid leukemia (AML) will be delivered via oral presentation.

Two recently enrolled BPDCN patients have received a single 5-day cycle of SL-401, and there has been one new complete response (CR). To date, 8 (7 evaluable for response) BPDCN patients have been treated with a single 5-day cycle of SL-401; there have been 5 CRs and 1 PR (86% overall response rate). In addition, one of these patients who had a CR lasting several months was subsequently retreated with SL-401 on a compassionate basis following relapse. The patient had clearance of skin lesions but subsequently developed disease progression in the bone marrow off therapy; no notable adverse events occurred. BPDCN patients treated with SL-401 have not had dose-limiting toxicity to date.

Eric K. Rowinsky, M.D., Chief Medical Officer and Head of Research and Development at Stemline Therapeutics, commented, "The results being presented at ASH, including a new CR, continue to validate SL-401's robust clinical activity in patients with BPDCN, as well as its clinical potential in multiple other IL-3R expressing cancers based on its potent activity in experimental models." He continued, "It is gratifying to observe robust responsiveness in previously treated patients with BPDCN and AML, especially after receiving only a single cycle of SL-401. We think that this represents the tip of the iceberg with regard to the potential clinical activity of SL-401, which will likely be substantially increased upon repetitive administration (i.e. every several weeks) that is standard for anticancer therapeutics. We are also greatly encouraged to see that a second cycle of SL-401 can be delivered safely and demonstrate activity even in a sub-optimal situation where a patient has been off drug for months and is actively relapsing. Unfortunately we were unable to administer additional cycles to this patient. However, in studies going forward we plan to maximize the clinical benefit of SL-401 as patients will receive multiple consecutive cycles of therapy."

About SL-401 and SL-101

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, chronic myeloid leukemia (CML), chronic eosinophilic leukemia, and certain lymphomas. SL-101, a next generation IL-3R targeted therapy, is a novel antibody-drug conjugate (ADC) that targets the alpha chain of IL-3R (CD123). SL-101 has demonstrated preclinical activity against a variety of cancer types.

Five abstracts were accepted for the 2013 ASH meeting, including four posters and one oral presentation. Details on the presentations are as follows:

The meeting abstracts can be viewed online through the ASH website at www.hematology.org.

About Stemline Therapeutics, Inc.

Stemline Therapeutics, Inc. is a clinical-stage biopharmaceutical company developing novel oncology therapeutics that target both cancer stem cells (CSCs) as well as the tumor bulk. 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 pivotal programs in blastic plasmacytoid dendritic cell neoplasm (BPDCN) and third-line acute myeloid leukemia (AML) as well as other clinical studies in additional hematologic cancers. SL-701 is being advanced into later stage trials of adults with second-line glioblastoma multiforme (GBM) and children with brainstem and non-brainstem glioma. 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 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.