Announces L-DOS47 and Checkpoint Blockade Collaboration with Moffit Cancer Center

(Toronto, Ontario) – Helix BioPharma Corp. (TSX, FSE: “HBP”) (“Helix” or the “Company”), an immuno-oncology company developing innovative drug candidates for the prevention and treatment of cancer, today announced that it has entered into a collaboration agreement with Moffitt Cancer Center to perform basic research studies to further investigate the pharmacodynamics of L-DOS47 and determine the
potential benefits of combining L-DOS47 with immune checkpoint inhibitors.

Cancer immunotherapies, such as immune checkpoint blockade or adoptive T-cell transfer, can lead to durable responses in the clinic. However the effectiveness of these therapies can be influenced by a number of factors unique to the tumor’s microenvironment. Work conducted by Moffitt Cancer Center determined that an acidic pH tumour microenvironment is one of those factors that may lower the efficacy of these therapies. Neutralizing tumour acidity impaired the growth of some cancer types in mice where it was associated with increased T cell infiltration. As a result, raising intratumoral pH may improve responses to immunotherapy. Urease, the active component of L-DOS47, alters the pH of the local tumour milieu resulting in alkalinization of the local tumour environment.