The technology was developed by scientists at the University Health Network, the University of Toronto, through the Toronto Recombinant Antibody Centre (TRAC), and The Hospital for Sick Children (SickKids), in Toronto, Ontario.
SIRPa is the ligand of CD47, a molecule upregulated on many hematological and solid tumors. CD47 delivers a “do not eat” signal that suppresses macrophage phagocytosis, allowing cancer cells, including cancer stem cells, to escape immune-mediated destruction. Stem Cell Therapeutics (SCT) is currently developing a CD47 antagonist, using a modified version of the native SIRPa protein fused to an immunoglobulin Fc region. This SIRPaFc fusion protein has shown remarkable anti-leukemic activity both in vitro and in human xenograft models, and SCT recently announced that the program has entered the IND-enabling phase of drug development. The company expects to report further updates at the upcoming annual meeting of the American Society of Hematology (December 7-10, 2013).
“Targeting the CD47/SIRPa pathway can eliminate both bulk cancer cells and cancer stem cells, and engages both the innate and the adaptive arms of the immune system,” commented SCT’s Chief Scientific Officer, Dr. Bob Uger. “Antibody blockade of SIRPa is a promising approach to activate the anti-tumor activity of macrophages against both liquid and solid tumors, and has the potential as both a monotherapy and combination therapy with other anti-cancer antibodies.”
“The CD47/SIRPa axis is one of the most promising and compelling next-generation immunotherapy targets in the fight against cancer,” remarked SCT’s Chief Executive -2- Officer, Dr. Niclas Stiernholm. “Having recently announced the advancement of our SIRPaFc program into formal IND-enabling studies, a program we believe is the best-inclass CD47 antagonist currently in development, reinforcing our industry-leading position in this pathway with a complementary antibody program against the SIRPa protein makes eminent sense.”
The execution of the definitive license agreement is subject to final due-diligence and certain conditions being met by SCT over the next nine months. The license agreement will contain customary terms and provisions for assets at this stage of development, including an initial license consideration, milestone payments, royalties on sales and sublicensing terms.