Stemline Therapeutics Announces SL-401 Receives EU Orphan Drug Designation for Treatment of BPDCN

NEW YORK, Nov. 2, 2015 (GLOBE NEWSWIRE) — Stemline Therapeutics, Inc. (Nasdaq:STML) announced today that the European Medicines Agency (EMA) has granted Orphan Drug designation to SL-401 for the treatment of blastic plasmacytoid dendritic cell neoplasm (BPDCN). Recently, SL-401 received Orphan Drug designation from the EMA for acute myeloid leukemia (AML), and from the U.S. Food and Drug Administration (FDA) for the treatment of AML and BPDCN.

SL-401 is a targeted therapy directed to the interleukin-3 receptor (IL-3R) present on cancer stem cells (CSCs) and tumor bulk of BPDCN, AML, and other hematologic cancers. Stemline is evaluating SL-401 in multiple clinical programs, including an ongoing pivotal trial in BPDCN as well as trials in additional hematological cancers.

Ivan Bergstein, M.D., Stemline’s CEO, commented, “We are pleased with the EMA’s decision to grant Orphan Drug designation to SL-401 for BPDCN, an aggressive and deadly disease with few effective treatment options.” Dr. Bergstein continued, “SL-401 now has Orphan Drug status in the U.S. and Europe for both AML and BPDCN, which underscores the unmet medical need in these disorders, and provides us with options for potential accelerated clinical development.”

About Orphan Drug Designation

Orphan Drug designation by the European Commission provides regulatory and financial incentives for companies to develop and market therapies that treat a life-threatening or chronically debilitating condition affecting no more than five in 10,000 persons in the European Union (EU), and where no satisfactory treatment is available. In addition to a 10-year period of marketing exclusivity in the EU after product approval, orphan drug designation provides incentives for companies seeking protocol assistance from the EMA during the product development phase, and direct access to the centralized authorization procedure.

About Stemline Therapeutics

Stemline Therapeutics, Inc. is a clinical stage biopharmaceutical company developing novel oncology therapeutics that target cancer stem cells (CSCs) and tumor bulk. Stemline is developing two clinical stage product candidates, SL-401 and SL-701, and preclinical candidates that include SL-801. SL-401 is a targeted therapy directed to the interleukin-3 receptor (IL-3R) present on CSCs and tumor bulk of a wide range of hematologic cancers. Several multicenter clinical trials with SL-401 are currently open in a variety of indications. Patients are currently being enrolled in the expansion stage of the SL-401 pivotal trial in relapsed/refractory blastic plasmacytoid dendritic cell neoplasm (BPDCN). This follows recent completion of the lead-in stage of this trial that enrolled first-line and relapsed/refractory BPDCN and relapsed/refractory acute myeloid leukemia (AML) patients at escalating doses and confirmed the dose and schedule for the current expansion stage. A previous Phase 1/2 trial with SL-401 demonstrated major responses, including complete responses (CRs), in both first-line and relapsed/refractory BPDCN as well as relapsed/refractory AML (Frankel et al. Blood 124, 2014). Clinical studies with SL-401 are also open in additional malignancies including AML in CR with minimal residual disease (MRD) and several high-risk myeloproliferative neoplasms (MPN). SL-701, an immunotherapy designed to activate the immune system to attack tumors, is being developed in adult patients with second-line glioblastoma multiforme (GBM). SL-801, a novel oral small molecule reversible inhibitor of XPO1, is currently being advanced toward investigational new drug (IND) filing for clinical development in a variety of solid and hematologic 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 clinical trials and preclinical studies for our product candidates, including site initiation, internal review board approval, scientific review committee approval, patient accrual, safety, tolerability and efficacy data observed, and input from regulatory authorities; our plans to develop and commercialize our product candidates; our available cash and investments; our ability to obtain and maintain intellectual property protection for our product candidates; 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.

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