Stem Cell Therapeutics Corp. has provided the following six-month corporate update:
• Pilot non-human primate tolerability studies have been completed using SIRPaFc, Stem Cell Therapeutics’ proprietary CD47 antagonist. Three separate human SIRPaFc proteins, possessing different Fc regions with varying levels of effector function, were evaluated in a repeat-dose regimen in cynomolgus macaques. Safe dosing levels, substantially above the anticipated human therapeutic dose, were established for each drug candidate. Greater tolerability was observed to correlate with decreasing effector function. Anemia and thrombocytopenia were the primary adverse events observed, which in most cases were asymptomatic and reversible.
These studies, while preliminary in nature, provided firm support for moving the SIRPaFc program forward into the next development phase. In parallel with conducting the manufacturing activities and toxicology studies typically associated with the IND-enabling phase of drug development, the company will significantly amplify its preclinical efficacy studies. This will be critical in order to uncover the full potential of this promising immune checkpoint inhibitor and to expand its use in the treatment of both solid and liquid tumors.
• Preclinical SIRPaFc efficacy data in an acute myeloid leukemia xenograft model was recently reported at the 55th Annual Meeting of the American Society of Hematology (ASH). SIRPaFc was shown to promote potent anti-leukemic responses at low doses. When combined with the non-human primate tolerability data, this indicates a wide therapeutic window. For details on the ASH presentation please consult our website at www.stemcellthera.com.
• On December 13, 2013, the company completed a $33 million private placement, principally with participation from experienced U.S. healthcare institutional investors. Importantly, this substantial financing, one of the largest by a Canadian biopharmaceutical company last year, was primarily driven by the strength and promise of the SIRPaFc technology. Its proceeds will allow the company to execute an optimal development program over the next three years, which will include manufacturing, formal toxicology testing, as well as clinical studies in cancer patients.
• Dosing in the investigator-driven Phase I multicenter dose-escalation study (50mg-350mg) with tigecycline in patients with relapsed or refractory acute myeloid leukemia (AML) is nearing completion. Dosing has advanced to the 350mg cohort, a dose level that greatly exceeds the 100mg dose approved for anti-infective use and is well within the range of doses that have demonstrated anti-cancer activity in published preclinical studies. Patient recruitment has been slowed by the submission of a protocol amendment.
The cost of this study has been covered by the academic sponsor. As the exclusive licensee of this technology, the company continues to monitor the progress of the trial and anticipates its completion in 2014. Following a thorough evaluation of the clinical data and the program’s commercial potential the company will decide on an appropriate path forward.