Stemline Therapeutics’ lead compound SL-401 has received Orphan Drug designation from FDA for the treatment of acute myeloid leukemia (AML). The orphan designation helps to support the development of new therapies that treat rare diseases and offers incentives such as seven years of marketing exclusivity, tax credits, and clinical development grants, as well as a waiver of Prescription Drug User Fee Act (PDUFA) filing fees.

SL-401 has completed a multi-center Phase I/II trial in AML demonstrating single agent efficacy, including two durable complete responses (CRs), multiple blast reductions and disease stabilizations, as well as an overall survival (OS) benefit in heavily pre-treated patients. SL-401 was well tolerated and bone marrow-sparing. SL-401 will now enter Phase III trials in patients with advanced AML.

Stemline’s chief executive officer, Ivan Bergstein, said, “Receipt of Orphan Drug designation represents another key milestone in the advancement of SL-401 through the regulatory process. We are also very encouraged by the potential of SL-401 to benefit patients with advanced stage AML, an unmet medical need, as well as additional hematologic malignancies including MDS, CML and potentially certain lymphomas.”