X-linked retinoschisis (XLRS) is an inherited, monogenetic ocular disease caused by mutations in the retinoschisin (RS1) gene, resulting in the development of cystic cavities throughout the retina and leading to juvenile macular degeneration. Approximately 1:15,000 males in the US are affected, classifying the condition as an orphan indication.
Human leukocyte antigen (HLA) LOH (LOH) is a known resistance mechanism by which cancers evade T cell receptor-(TCR-)based immunotherapies. This class of therapies includes immune checkpoint inhibition (ICI, e.g., Pembrolizumab), engineered TCR (T cell receptor)-T cell adoptive transfer, tumor infiltrating lymphocytes (TIL), T-cell engagers, and other modalities. Dozens of therapies in this category were developed with many in clinical trials. The resistance mechanism noted here, HLA LOH, causes these therapies to fail.