WHO had recommened rapid ART initiation, defined as starting ART within 7 days or on the same day after HIV diagnosis, to improve HIV care continuum. Prior studies revealed that point-of-care diagnostic methods for the detection of HIV RNA can accelerate linkage to care and reduce anxiety. By shortening the interval between infectious disease physician referral, time-lag between screening and confirmatory tests, with the use of the newly developed point-of-care immunochromatographic confirmatory test, initiating a safe and potent antiretroviral therapy, BIC/F/TAF, on the same day of HIV confirmation will be feasible to improve linkage to care and to shorten the interval between HIV diagnosis and viral suppression.

Background In 2015, WHO recommended that all patients be treated with combination antiretroviral therapy (cART) once the diagnosis of HIV infection was made. On the population level, starting cART soon after HIV diagnosis can prevent onward HIV transmission. Although WHO has recommended "treat-all" policy since 2015, there were still 1.8 million people becoming newly infected with HIV in 20179. The substantial loss of patients during the HIV care continuum among the most vulnerable populations have been major concerns in the cART scale-up. Therefore, the concept of rapid ART initiation, defined as starting ART within 7 days or even on the same day after HIV diagnosis was confirmed, was introduced to improve HIV care continuum. In several clinical trials, loss to follow-up was observed despite the clinical trial settings. From our prior study18, among 786 individuals who were screened positive for HIV, 2.4% never returned to the clinic for the confirmatory tests. Despite ART scale-up and the policy of rapid initiation, 30% the of patients who were diagnosed with HIV infection during 2017-2018 did not initiate cART within 7 days after HIV diagnosis was made. Prior studies revealed that point-of-care diagnostic methods for detection of HIV RNA can accelerate linkage to care and reduce anxiety. However, the cost of and the barriers to accessing the point-of-care HIV RNA testing remain high. By shortening the interval between infectious disease physician referral, time-lag between screening and confirmatory tests, with the use of newly developed point-of-care immunochromatographic confirmatory test, initiating a safe and potent antiretroviral therapy on the same day of HIV confirmation will be feasible to improve linkage to care and to shorten the interval between HIV diagnosis and viral suppression.

Study aim This study objective is to investigate the feasibility and outcomes of same-day initiation with Biktarvy (Bic/F/TAF) among patients who receive a diagnosis of HIV infection by confirmatory test.

Study Interventions This is a multi-center, single-arm, prospective cohort study. All individuals who fulfill the inclusion/exclusion criteria will be enrolled in our study and followed for 48 weeks. During the first visit at ID clinic, baseline clinical data will be collected by history taking, physical examination, and blood testing. The confirmatory test and baseline evaluations will be performed at the Visit 1. The test results will also be reported on the same day. Patients, who are HIV(+) by confirmatory test ,will receive a 7-day Biktarvy treatment and the first dose will be administered from Visit 1 (Day 1). The results of other evaluation including viral load, CD4 count, and coinfection will be available at visit 2.

At Visit 2, the clinical symptoms and the tolerability will be recorded. If participants continue to receive Biktarvy® at the discretion of the HIV treating physicians, Biktarvy will be continued according to the national HIV treatment guidelines, which will be reimbursed by the National Health Insurance, and the patients will be followed in our study for 48 weeks. If the patients are switched to other cART regimens than Bictarvy according to physician's clinical judgements, the participants will continue their follow-up in the study.

During the follow-up period, clinical information on symptoms, tolerability, and adverse effects with the use of face-to-face questionnaire interviews, and follow-up laboratory test results will be collected. to evaluate the efficacy and adverse effect according to the national HIV treatment guidelines and routine clinical practices.

Monitor of Adverse event and management The subjective adverse events will be inquired during each visit and recorded with the use of questionnaire interviews. According to the national HIV treatment guidelines in Taiwan, the liver and renal functions and muscle enzymes will be followed during treatment as part of the standard of care. The study team will provide best clinical care if adverse events develop and the cost of medical care required will be covered by the insurance company. Severe adverse event and withdrawal from the study will be reported to the primary investigator on a monthly basis. When the number of drop-out is higher than 30%, the enrollment will be stopped temporarily until the investigation ensures the safety of the participants.

Study Endpoints

1. Primary endpoints 1) The rate of retention in care at Week 48 2) The proportion of viral suppression (<50 copies/ml) at Week 48
2. Secondary endpoints 1) The rate of same-day initiation of ART among patients who receive a confirmed diagnosis of HIV infection 2) The proportion of viral suppression (<200 copies/ml) at Weeks 1, 4, and 48 3) Any/severe adverse effect of B/F/TAF before Weeks 4 and 48 4) Patient's satisfaction at Weeks 1, 4, and 48

Statistical analysis

1. This is a feasibility study aiming to investigate the rate of engagement in same-day ART initiation and retention in care at Week 48. No sample size calculation is needed. The sample size of 200 participants is estimated by taking into account the case numbers of newly diagnosed HIV-positive patients seeking HIV care and cART at each participating hospitals during the past 1 year.
2. Timetable for study and enrollment:

1) Total subjects expected to be enrolled: 200 2) Total subjects expected to enter treatment: 195 3) Total subjects expected to complete treatment: 191 4) Duration of enrolled period: 20 months 5) Number of subjects entering treatment per month: 10 ( 2 subjects per site)

Inclusion Criteria:

• Patients who test positive by HIV screening tests (4th generation Ag/Ab) by clinical care providers or by VCT counselors within 3 days of Visit 1.
• Aged 20 years or older
• Patient is willing to participate in this study and sign the written informed consent form

Exclusion Criteria:

• Prior HIV diagnosis
• Prior ART for HIV infection
• Chronic kidney disease, stage ≥4 (CCr <30 ml/min/1.73m2) or receiving dialysis
• Severe hepatic impairment (Child-Pugh score C) or clinical apparent hepatic impairment including jaundice or ascites
• Active or latent tuberculosis infection or clinical apparent central nervous system infection
• Pregnancy or breastfeeding
• Allergy to FTC or TDF containing medication