Apricoxib, (CS-706, 1) 2-(4-ethoxyphenyl)-4-methyl-1-(4-sulfamoylphenyl)-pyrrole, a small-molecule, orally active, selective COX-2 inhibitor was discovered by investigators at Daiichi Sankyo in 1996. Apricoxib binds to and inhibits the enzyme cyclooxygenase-2 (COX-2), thereby inhibiting the conversion of arachidonic acid into prostaglandins. Apricoxib-mediated inhibition of COX-2 may induce tumor cell apoptosis and inhibit tumor cell proliferation and tumor angiogenesis. COX-related metabolic pathways may represent crucial regulators of cellular proliferation and angiogenesis. Clinical studies demonstrated potent analgesic activity and preclinical studies demonstrated good pharmacokinetics, pharmacodynamics and gastrointestinal tolerability. As an anticancer agent, preclinical studies demonstrated efficacy in biliary tract cancer models and colorectal carcinoma. Phase IIa trial data indicated that apricoxib was a potent analgesic in the treatment of pain in postoperative dental surgery. Apricoxib, a novel once-daily selective cyclooxygenase-2 inhibitor, was investigated in combination with erlotinib for recurrent stage IIIB/IV nonsmall cell lung cancer. Apricoxib plus erlotinib was well tolerated and yielded a 60% disease control rate. A phase II trial was investigating 400 mg/day apricoxib plus 150 mg/day erlotinib in patients selected based on change in urinary PGE-M. However, in 2015 development was abandoned due to poor clinical trial results.