Stemline Reports Five Presentations, Will Offer Update on SL-401 Trial from Ongoing Pivotal BPDCN Trial at ASH Meeting

Stemline Therapeutics, Inc.

announced today that SL-401 and SL-801 will be the subject of five poster presentations at the 2015 American Society of Hematology (ASH) Annual Meeting, being held December 5-8, 2015 at the Orange County Convention Center in Orlando, FL. Investigators will present updated clinical data from the lead-in and ongoing expansion stages of the SL-401 pivotal trial in blastic plasmacytoid dendritic cell neoplasm (BPDCN), as well as three additional presentations highlighting preclinical data supporting SL-401's clinical development in mastocytosis as a single agent and in multiple myeloma in combination with approved agents. SL-801 will be the subject of a presentation detailing its broad preclinical anti-cancer activity in both solid and hematologic cancers in anticipation of the start of clinical trials. Ivan Bergstein, M.D., Stemline's Chief Executive Officer, commented, "On Monday evening, investigators will present initial efficacy and safety data from the lead-in and ongoing expansion stages of the SL-401 pivotal trial in BPDCN. We are very pleased with the initial outcomes of the ongoing study. Our experience from the lead-in stage enabled us to develop a regimen with specific dosing parameters that, since implementation, has generated a therapeutic window with manageable safety and high levels of clinical activity." Details on the presentations are listed below and abstracts are available on the ASH conference website. Additionally, all abstracts and posters will be available on the Stemline website soon after the presentations. SL-401 Presentations Lead-in Stage Results of a Pivotal Trial of SL-401, an Interleukin-3 Receptor (IL-3R) Targeting Biologic, in Patients with Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) or Acute Myeloid Leukemia (AML) Lead Author: Marina Konopleva, MD, PhD Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX Date: Monday, December 7, 2015 Presentation Time: 6:00 PM - 8:00 PM Location: Orange County Convention Center, Hall A A Novel Agent SL-401 Triggers Anti-Myeloma Activity By Targeting Plasmacytoid Dendritic Cells: Implications for a Novel Immune-Associated Mechanism 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 Date: Sunday, December 6, 2015 Presentation Time: 6:00 PM - 8:00 PM Location: Orange County Convention Center, Hall A Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) Patient-Derived Xenografts Are Faithful Genomic and Phenotypic Models of Primary Leukemia and Respond to the IL3 Receptor Targeting Agent SL-401 In Vivo Lead Author: Amanda Christie, B.A. Department of Hematologic Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA Date: Monday, December 7, 2015 Presentation Time: 6:00 PM - 8:00 PM Location: Orange County Convention Center, Hall A CD123 Immunostaining in Systemic Mastocytosis: Differential Expression in Disease Subgroups and Potential Prognostic Value Lead Author: Animesh Pardanani, MBBS, Ph.D. Department of Hematology, Mayo Clinic College of Medicine, Rochester, MN Date: Sunday, December 6, 2015 Presentation Time: 6:00 PM - 8:00 PM Location: Orange County Convention Center, Hall A SL-801 Presentations SL-801, a Novel, Reversible Inhibitor of Exportin-1 (XPO1) / Chromosome Region Maintenance-1 (CRM1) with Broad and Potent Anti-Cancer Activity Lead Author: Janice Chen, Ph.D. Stemline Therapeutics, Inc., New York, NY Date: Monday, December 7, 2015 
 Presentation Time: 6:00 PM - 8:00 PM 
 Location: Orange County Convention Center, Hall A