Stemline Therapeutics Clears First Cohort of Patients in Ongoing SL-801 Phase 1 Trial

NEW YORK, May 03, 2016 (GLOBE NEWSWIRE) — Stemline Therapeutics, Inc. (Nasdaq:STML) announced today that it has completed the initial dosing cohort in its SL-801 Phase 1 advanced solid tumor trial. The second cohort is currently open. SL-801 is a novel, oral, small molecule that reversibly inhibits the XPO1 (Exportin-1) nuclear transport protein, a clinically validated target active in a wide variety of cancer types.

This Phase 1 dose escalation trial will enroll up to 50 patients with advanced solid tumors at multiple centers in the U.S. The trial is designed to evaluate safety, identify an optimal dosing regimen, and detect potential signals of efficacy in one or more cancer types.

Ivan Bergstein, M.D., Stemline’s Chief Executive Officer, stated, “We are very pleased to have dosed the first patients in our SL-801 program during the first quarter, in-line with our expectations, and recently cleared the first dosing cohort. We are continuing to enroll patients with a wide range of solid cancer types in this trial in order to identify specific indications with both sensitivity to the agent as well as viable registration pathways. We believe we can leverage the unique properties of this compound along with our knowledge of the XPO1 space to create significant value from the program early on.”

About Stemline Therapeutics
Stemline Therapeutics, Inc. is a clinical stage biopharmaceutical company developing novel oncology therapeutics. Stemline is developing three clinical stage product candidates, SL-401, SL-701, and SL-801. A potentially pivotal Phase 2 trial with SL-401, a targeted therapy directed to the interleukin-3 receptor (IL-3R; CD123) present on a wide range of hematologic cancers, is currently enrolling patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN). Data from the initial stage of this ongoing trial demonstrated high overall response rates, with multiple complete responses (CRs). Patients in remission are being followed for response duration and outcomes as new patients continue to enroll into the study. In addition, ongoing Phase 1/2 trials with SL-401 are currently enrolling patients with additional malignancies including acute myeloid leukemia (AML) with minimal residual disease (MRD) and high-risk myeloproliferative neoplasms (MPN). A Phase 2 trial with SL-701, an immunotherapy designed to activate the immune system to attack tumors, is currently enrolling adult patients with second-line glioblastoma multiforme (GBM). SL-801, a novel oral small molecule reversible inhibitor of XPO1, is currently enrolling patients in a Phase 1 clinical trial in advanced solid tumors. 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.

CONTACT: Contact
Investor Relations
Stemline Therapeutics, Inc.
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New York, NY 10022
Tel: 646-502-2307
Email: investorrelations@stemline.com