14C RPT193

14C RPT193 is a radiolabeled form of RPT193 (zelnecirnon), an orally administered small molecule antagonist of the human C-C motif chemokine receptor 4 (CCR4). The drug was developed by RAPT Therapeutics for the treatment of inflammatory diseases such as atopic dermatitis and asthma. Its mechanism involves selectively inhibiting CCR4, thereby blocking the migration and activation of T-helper type 2 (Th2) cells into inflamed tissues—a key driver in allergic inflammation. Clinical studies demonstrated that oral administration was generally well tolerated and showed clinical improvement in atopic dermatitis patients; however, development was halted following a serious adverse event (liver injury) in a Phase 2 trial[1][2][8]. The "14C" prefix indicates use in absorption/metabolism studies with radiolabeling to track pharmacokinetics[6][9].