Cara’s hypothesis in developing Korsuva was that by acting on opioid receptors, the experimental drug could provide relief from itching without leading to addiction. Rather than stimulating the mu-opioid receptor, like morphine and other pain drugs with addictive potential, Korsuva activates kappa opioid receptors.
The global Phase 3 KALM-2 trial enrolled 473 patients to receive either Korsuva or a placebo after each dialysis session, with a goal of reducing the severity of their worst itch by at least three points on a 10-point scale. Of patients treated with Korsuva, 54% reported a three-point reduction, significantly more than the 42% taking placebo.