Abstract 3382: Detection of cancer in dogs using a novel genetic-based synthetic biomarker platform

Early detection of cancer is an important driver of increased survival, quality of life and reduced healthcare costs. Although liquid biopsy provides a new option for early cancer detection, the limitations of detecting a few molecules of blood-based biomarkers naturally shed by the cancer remain. Earli is developing a highly sensitive, orthogonal approach that uses a genetic construct that usurps dysregulated pathways and actively forces cancer cells to drive the expression of a detectable ‘synthetic’ biomarker. We previously used murine xenograft models to validate the tumor detection properties of EARLI-001, a circular DNA containing a human derived cancer-activated promoter to drive the transient expression of secreted embryonic alkaline phosphatase (SEAP), a protein normally expressed only during fetal development. Biodistribution following intravenous (IV) administration of EARLI-001 shows a broad tissue tropism, enabling the potential to monitor multiple tissues for malignant cells. A single dose of EARLI-001 administered in a pulmonary metastatic cancer mouse model resulted in a 95-fold increase in serum SEAP compared to healthy controls. Recognizing the inherent limitations of murine models, we evaluated EARLI-001 in canines diagnosed with cancer. Dog cancers share many features with human malignancies including spontaneous tumor formation, heterogeneity, growth kinetics, histology, and comparable dysregulated genetic pathways. Furthermore, the use of dogs allows the study of EARLI-001 in an immune competent setting and with substantially increased size (up to 65 kg) comparable to scaling into human subjects. EARLI-001 was first tested for safety and biodistribution in 54 purpose-bred beagles in MTD and GLP toxicology studies which reveal that it is safe and well tolerated across a broad range of clinical doses. Biodistribution analysis in 12 tissues showed nanoplasmid levels peaking in the first days post dose and rapidly decreased to background levels by 60 days. These non-tumor bearing dogs showed no serum SEAP signal at all doses. Following IACUC approval and informed owner consent, EARLI-001 was administered to companion dogs in a standard 3 x 3 dose escalation study, with an expanded mid-range cohort. These companion dogs harbored a wide variety of spontaneous tumors in different tissues of origin. In tumor bearing dogs, EARLI-001 elicited a clear and discernable cancer-activated SEAP signal in 1 of 3 dogs dosed at 0.01 mg/kg, 3 of 6 dosed a