In China, free first-line ART regimens typically consist of two nucleoside reverse transcriptase inhibitors (NRTIs) and a non-nucleoside reverse transcriptase inhibitor (NNRTI). As of the end of 2022, approximately 1.135 million individuals were receiving ART, achieving a coverage rate of 92.8%, largely due to participation in free treatment programs. However, around 36,000 patients have discontinued treatment, primarily due to side effects associated with Efavirenz (EFV), a common NNRTI. The challenges posed by side effects and resistance profiles of existing NNRTIs highlight the need for effective re-initiation of ART to improve overall treatment coverage. INSTIs, particularly B/F/TAF (Bictegravir/emtricitabine/tenofovir alafenamide), demonstrates effective viral suppression and a higher barrier to resistance than NNRTIs. B/F/TAF has shown efficacy in patients with resistance mutations, making it a strong candidate for same-day ART re-initiation, especially in resource-limited areas where genotypic resistance testing may be unavailable. This study aims to evaluate the feasibility and effectiveness of rapidly restarting B/F/TAF in patients with treatment interruptions from previous NNRTI regimens.

Inclusion Criteria:

• Patients with 18 years old or above.
• Discontinuation of previous NNRTI based regimen for more than 90 days.
• No known CrCl< 30mL/min or severe hepatic impairment.
• No known or suspected resistance to BIC.
• No known pregnancy

Exclusion Criteria:

••Patients who are pregnant.

• Patients who have abnormal liver and kidney function indicators(Child-pugh class C, CrCl< 30).Hepatitis virus co-infection does not serve as an exclusion criterion.
• Patients who have historic resistance test indicating drug resistant to BIC or baseline resistance test indicating resistance to BIC.
• Patients who are psychiatric illness or active tuberculosis co-infection.