OPRK1 and myeloid sarcoma: An unmet clinical needfor safer and effective analgesics and theopioid crisis have unlocked the therapeutic potential of the KOR.28 Difelikefalin, a peripherally acting tetrapeptideKOR agonist, has recently been approved to treat postoperative pain.41 Further, G protein-biased KOR ligands hold promiseto develop next-generation analgesics with fewer central dysphoric-and sedative-like side effects for the treatment of chronic pain.42,43 The recent discovery that KOR agonism mediates beneficial effectsin the EAE mouse model augments its therapeutic potential to developnovel MS therapies.