Tenidap was a COX/5-LOX inhibitor and cytokine-modulating anti-inflammatory drug candidate that was under development by Pfizer as a promising potential treatment for rheumatoid arthritis, but Pfizer halted development after marketing approval was rejected by the FDA in 1996 due to liver and kidney toxicity, which was attributed to metabolites of the drug with a thiophene moiety that caused oxidative damage.
^Wylie G, Appelboom T, Bolten W, Breedveld FC, Feely J, Leeming MR, et al. (June 1995). "A comparative study of tenidap, a cytokine-modulating anti-rheumatic drug, and diclofenac in rheumatoid arthritis: a 24-week analysis of a 1-year clinical trial". British Journal of Rheumatology. 34 (6): 554–63. doi:10.1093/rheumatology/34.6.554. PMID7543348.