Discovery Program

Sonodynamic Therapy with SL052

Quest is also investigating the use of SL052 for sonodynamic therapy applications. Sonodynamic therapy is a promising new modality for cancer treatment based on the synergistic effect on tumor cell killing by the combination of a drug (typically a photosensitizer) and ultra-sound. The mechanism of sonodynamic action was suggested to involve excitation of the sensitizer by sonoluminescent, with subsequent formation of singlet oxygen.

The company has identified Peritoneal Carcinomatosis as an ideal indication for such applications. HB based SDT is designed to be more effective than current treatments in addressing the dual tumor burden in peritoneal carcinomatosis and pleural effusion: freely floating cells, as well as micrometastases seeded onto mesothelial surfaces within the abdomen and thorax. Quest is establishing the use of SL052 as a sonosensitizer using in-vitro cell-survival assays and in-vivo animal tumor model systems to address its utility in this indication.

PDT Immunotherapy

Photodynamic therapy (PDT) has been considered as especially suitable for combining with various types of immunotherapy for clinical treatment of targeted lesions such as solid cancers. Pre-clinical studies demonstrate that, in addition to the direct local cytotoxicity, PDT can induce host immune responses, which may further enhance the therapeutic effects on the primary tumor as well as metastasis. Therefore, PDT induced antitumor immune response might play an important role in successful control of malignant
diseases.

With a strong intellectual property position to use SL052 with immunotherapy, the Company has received encouraging results from its collaborative research agreement with the BC Cancer Agency to investigate the therapeutic and mechanistic aspects of anti-tumor effect achieved in mice by treatment combining photodynamic therapy based on SL052 with various immunotherapeutic agents. The results demonstrate that SL052 is an effective immuno-stimulant when combined with immunotherapy for the removal of solid tumors.