PF-4191834 is a noniron chelating, non-redox inhibitor of the 5-lipoxygenase enzyme (5-LOX) that is being developed as an oral anti-inflammatory therapy for the treatment of asthma. Enzyme assay results demonstrate that PF-4191834 has an improved potency compared with its predecessor CJ-13610 and of zileuton. It was able to reduce pain and inflammation in an adjuvant-induced arthritis model in rats. PF-4191834 offers the potential to test the hypothesis that chronic inhibition of the 5-LOX enzyme will provide maximal efficacy for this target in inflammatory diseases such as asthma, chronic obstructive pulmonary disease, pain, and perhaps lupus. PF-4191834 had been in phase II clinical trial for the treatment of pain. Development was terminated in March 2011.