Researchers examined virologic outcomes throughout 48 weeks of treatment with of bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) in patients who have preexisting primary integrase strand transfer inhibitor resistance (INSTI-R). The preexisting INSTI-R was assessed retrospectively from 7 B/F/TAF studies by historical genotypes and/or RNA or DNA sequencing at baseline. Measurement of viral loads was completed at all visits. Of 1907 participants, preexisting primary INSTI-R substitutions were found in 20, who were mainly Black, male, had HIV-1 subtype B, and baseline median CD4 counts of 594 cells/mm. The median age was 52 years of age. The group who had primary INSTI-R either achieved or maintained virologic suppression throughout 48 weeks of therapy with B/F/TAF.