Patrys Limited announced the publication of new preclinical data for its deoxymab antibody PAT-DX1. This data, from studies conducted in three different animal models, further demonstrates the unique ability of Patrys' PAT-DX1 antibody to cross the blood-brain barrier (BBB) and significantly inhibit the growth of both primary and secondary cancers in the brain. The publication, entitled "ENT2 facilitates brain endothelial cell penetration and blood-brain barrier transport by a tumor-targeting anti-DNA autoantibody", has been published in the leading, peer- reviewed journal The Journal of Clinical Investigation--Insight, and builds on data previously disclosed by Patrys. The investigators show that, like the full-size antibody 3E10, Patrys' humanised deoxymab fragment, PAT-DX1 uses the nucleoside transporter protein ENT2 to cross the BBB. Most antibodies are unable to cross either cell membranes or the BBB, which limits their use for certain applications such as treating cancers in the brain and intracellular targeting of therapeutic payloads. Patrys believes the unique ability of deoxymabs to be transported intact across cell membranes and the BBB using the ENT2 nucleoside transporter is likely to be related to the biology of these particular antibodies rather than provide a general mechanism that could be used for other antibodies. The investigators also demonstrated that PAT-DX1 is able to significantly inhibit the growth of tumours in three different models of cancer once it crosses the BBB. Two different models of glioblastoma (GBM Model 1 and GBM Model 2) were tested and treatment with PAT-DX1 resulted in a 47% (24 days v 17 days, p<0.01) and 25% (73 days v 58 days, p<0.02) improvement in median survival respectively. In both these models, human glioblastoma cells were implanted in the brain tissue of animals which were then treated with PAT-DX1 once tumours had become established in the brain. PAT-DX1 was also tested in a third animal model designed to replicate the metastases of breast cancer into brain tissue. In this model, a human breast cancer cell line that is known to migrate to the brain and establish metastatic tumours was injected into the bloodstream. This model is considered one of the most challenging brain tumour models to treat. The number of tumours established in the brain was significantly reduced (p<0.01) when animals were treated with PAT-DX1 and this reduction in brain cancer metastases resulted in a statistically significant 45% (45 days v 31 days, p<0.002) improvement in median survival. The ability of PAT-DX1 to cross the BBB, localise to both primary and secondary tumours in the brain, and then selectively kill cancer cells by blocking their DNA Damage Repair (DDR) systems highlights the potential for Patrys' deoxymabs to provide much-needed, new therapeutic options for the treatment of cancers located in the brain.