Figure 1: Patient disposition. IR-IR post48=remained on NVP IR twice daily after week 48; IR-XR post48=switched from NVP IR twice-daily regimen to NVP XR once-daily regimen after week 48; NVP IR=nevirapine immediate release; NVP XR=nevirapine extended release; XR-XR post48=remained on NVP XR once-daily regimen after week 48 (i.e., throughout study).