On the verge of top-line data from its phase IIb trial with oral small-molecule CC chemokine receptor 4 (CCR4) antagonist zelnecirnon in atopic dermatitis (AD), due around the middle of this year, Rapt Therapeutics Inc. said the U.S. FDA has imposed a clinical hold on that study with the otherwise promising drug, also known as RPT-193, in AD as well as the phase IIa trial with the same compound in asthma.