Additional Relevant Details CR845 is a peripherally acting kappa opioid receptor agonist currently in development for the treatment of acute and chronic pain and pruritus. The clinical hold was triggered by a protocol-specified stopping criterion, based on elevated serum sodium levels, that was met during the first phase of the study. A subsequent review of unblinded safety data from the first 90 patients dosed was completed byCara, the study’s Independent Data Monitoring Committee (IDMC), and the FDA.