ProMIS Neurosciences Designates PMN350 its Second Lead Product for Development in Alzheimer's Disease

TORONTO, Ontario and CAMBRIDGE, Massachusetts - May 24, 2017 - ProMIS Neurosciences (TSX:PMN), a company focused on discovery and development of precision treatments for neurodegenerative diseases, today announced that it has designated PMN350 - a monoclonal antibody (mAb) targeting toxic prion-like forms of amyloid-beta oligomers (AbetaO) - as the Company's second lead product for Alzheimer's disease (AD).

"We previously demonstrated that PMN310, our first lead product for development in Alzheimer's disease, presents the optimal target profile of selectively binding prion-like forms of AbetaO, inhibiting both their propagation and neurotoxicity," stated Dr. Neil Cashman, ProMIS Chief Scientific Officer. "We have now achieved a significant development milestone by demonstrating that PMN350, our second AD lead product directed against a different target on toxic AbetaO, also displays the optimal target product profile in both in vitro and in vivo tests."

The neuroprotective effect of PMN350 was investigated at SynAging, SAS, a leading contract research organization (CRO) specializing in neurodegenerative diseases. Injection of prion-like forms of AbetaO (also called toxic soluble oligomers) into the brains of mice causes a neurological deficit that can be assessed in a memory-behavior test called novel object recognition.  Normal mice exposed to an object remember the familiar object when re-exposed to it and spend more time exploring a newly introduced object. In contrast, AbetaO-injected mice lose the ability to discriminate between known and novel objects and spend equivalent amounts of time exploring both. Results obtained in this assay showed that administration of PMN350 to mice completely prevented the cognitive impairment caused by toxic oligomers. Furthermore, the observed cognitive benefit of PMN350 was correlated with a statistically significant improvement of two synaptic biomarkers (SNAP25, PSD95) and a biomarker of inflammation (TNFalpha) measured in hippocampal brain homogenates.

"We are pleased that our propriety discovery engine has produced a second lead product with the potential to treat Alzheimer's," commented Dr. Elliot Goldstein, ProMIS President and CEO. "With two lead development products, PMN310 and PMN350, each selectively addressing a different target (epitope) on toxic prion-like forms of amyloid-beta oligomers, we look forward to initial evaluation of their relative prevalence in cerebrospinal fluid samples from Alzheimer's patients, thereby paving the way for a precision medicine approach to this devastating disease."