Halofuginone (RU-19110) hydrobromid, a Febrifugine derivative, is a competitive prolyl-tRNA synthetase inhibitor with a K_i of 18.3 nM. Halofuginone hydrobromid is a specific inhibitor of type-I collagen synthesis and attenuates osteoarthritis (OA) by inhibition of TGF-β activity. Halofuginone hydrobromid is also a potent pulmonary vasodilator by activating Kv channels and blocking voltage-gated, receptor-operated and store-operated Ca²⁺ channels. Halofuginone hydrobromid has anti-malaria, anti-inflammatory, anti-cancer, anti-fibrosis effects^{[1][2][3][4][5]}.