Fosdevirine (also known as IDX899 and GSK-2248761) is another next generation NNRTI developed by Idenix Pharmaceuticals and ViiV Healthcare. It belongs to the family of 3-phosphoindoles. In vitro studies have shown comparable resistance profile to that of the other next generation NNRTIs. In November 2009 the candidate entered phase II clinical trials, but the trial and all further development was halted when 5 of 35 subjects receiving fosdevirine experienced delayed-onset seizures.