Stemline licenses clinically active oncology vaccine for dual targeting of tumor bulk and cancer stem cells

Stemline Therapeutics, Inc., a clinical stage biopharmaceutical company developing novel oncology compounds that target cancer stem cells (CSCs), today announced that it holds the license, from the University of Pittsburgh ("Pitt"), for the exclusive worldwide rights to a clinically active oncology vaccine directed to multiple defined targets on tumor bulk and CSCs. Developed by Dr. Hideho Okada, Associate Professor of Neurological Surgery and his colleagues at Pitt, the vaccine demonstrated safety, tolerability, and anti-tumor activity as a single agent in a Phase I, National Institutes of Health-funded study conducted at Pitt in 22 participants with recurrent high-grade glioma.

According to Dr. Okada's research findings, published recently in the Journal of Clinical Oncology, the most common grade 1-2 adverse events (AEs) were injection site reactions and fatigue. There were no grade 3 or 4 AEs. The vaccine elicited immune responses in 81% of evaluable patients. A high rate of overall response and disease stabilization was observed in this heavily pre-treated population, including 46% (6/13) in glioblastoma (GBM), and 67% (6/9) in anaplastic glioma (AG). Notably, there was one durable complete response (CR) of greater than 12 months in a 1st salvage GBM patient, and one partial response (PR) of 7 months duration in a 2nd salvage GBM patient. In both cases, the vaccine induced tumor shrinkage as determined by MRI according to standard RECIST criteria. A survival improvement over historical data was also observed in both the recurrent GBM and AG populations. The vaccine and its derivatives are being developed by Stemline under the name SL-701 as both an "off-the-shelf" peptide vaccine and a dendritic cell (DC) vaccine.

Tom Cirrito, PhD, Director of Operations at Stemline noted, "We became interested in Pitt's vaccine because of its dual targeting of both tumor bulk and cancer stem cells. In addition, by virtue of its targeting of multiple defined epitopes, we are able to determine the specificity and magnitude of the immune response in patients. Importantly, we have also observed reductions in tumor size as well as improvements in survival, consistent with the drug's mechanism of action."

Stemline's CEO, Ivan Bergstein, MD, commented on the in-licensing, "We are excited to add another clinical stage therapeutic to our pipeline. With this acquisition, we now have two clinical programs that have demonstrated complete responses and a survival benefit in heavily pre-treated populations. We are committed to a development strategy that rapidly advances these programs through the regulatory process toward commercialization."