Elvitegravir (via Quadro) and IDX899 are competing for the same slot: the addend to Truvada in first- and second-line HIV; however, there ought to be more than enough business to go around. For the sake of discussion, say Quadro eventually captures 50% of the Atripla market. This would still leave a huge market for a drug such as IDX899 that could supersede Sustiva in an updated version of Atripla consisting of Truvada plus an NNRTI.