Activated effector memory T-cells (TEM) have been implicated in the pathogenesis of autoimmune diseases.1 Activated TEM cells express high levels of the voltage-gated potassium channel Kv1.3, which functions to control cell excitability. Inhibition of Kv1.3 reduces the release of pro-inflammatory mediators, inhibits T-cell proliferation and migration to inflamed tissues, and has been shown to ameliorate autoimmune disease symptoms in preclinical animal models. However, small molecule Kv1.3 inhibitors have failed to deliver a successful drug into the clinic, in part due to lack of potency and selectivity.