Can Biktarvy (bictegravir, emtricitabine, and tenofovir alafenamide) be used as pre-exposure prophylaxis (PrEP) in sexually active adults at high risk of HIV acquisition with impaired renal function?

Biktarvy for PrEP in Patients with Renal Impairment

Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide) is NOT currently recommended as PrEP for any population, including those with impaired renal function, as it lacks efficacy data for HIV prevention and has not been studied or approved for this indication. 1, 2, 3

Current Evidence-Based PrEP Recommendations

First-Line PrEP Regimen

• TDF/FTC (tenofovir disoproxil fumarate/emtricitabine) remains the only recommended oral PrEP regimen with proven efficacy exceeding 90% when adherence is maintained across all populations at risk of HIV acquisition. 1, 2, 4, 5
• This recommendation is based on multiple randomized controlled trials (iPrEx, Partners PrEP, TDF2) demonstrating substantial risk reduction ranging from 44% to 86% depending on adherence. 1

Alternative for Specific Renal Situations

• TAF/FTC (tenofovir alafenamide/emtricitabine) is recommended ONLY for men who have sex with men (MSM) with creatinine clearance between 30-60 mL/min who have osteopenia, osteoporosis, or are at high risk for these complications. 1, 2
• TAF/FTC should be limited to cisgender men and others whose exposures do NOT include receptive vaginal sex or injection drug use alone, as efficacy data are lacking for these exposure routes. 3

Critical Renal Function Thresholds

Absolute Contraindications

• TDF-based PrEP is contraindicated when creatinine clearance falls below 60 mL/min/1.73 m². 1, 6
• Calculate creatinine clearance using the Cockcroft-Gault equation or measure eGFR before any PrEP prescribing decision. 6

When to Consider TAF/FTC Instead of TDF/FTC

For MSM specifically, consider switching from TDF/FTC to TAF/FTC when: 1, 2

• Creatinine clearance is 30-60 mL/min
• History of osteopenia or osteoporosis exists
• Age >50 years with bone health concerns
• Other renal risk factors are present (diabetes, hypertension)

Why Biktarvy Is Not Appropriate for PrEP

Lack of Prevention Data

• Biktarvy contains bictegravir (an integrase inhibitor), which has never been studied for HIV prevention. 1, 2
• While one study evaluated BIC/FTC/TAF for post-exposure prophylaxis (PEP) with favorable tolerability, PEP is fundamentally different from PrEP—PEP treats potential exposure after the fact, while PrEP prevents acquisition before exposure. 7
• No efficacy data exist for bictegravir in preventing HIV acquisition in uninfected individuals. 1, 2

Regulatory Status

• Biktarvy is FDA-approved only for HIV treatment, not prevention. 2, 3
• All current PrEP guidelines explicitly recommend only TDF/FTC or (in limited circumstances) TAF/FTC. 1, 2, 3

Practical Algorithm for PrEP Selection in Renal Impairment

Step 1: Calculate creatinine clearance 6

• Use Cockcroft-Gault equation or eGFR measurement

Step 2: Apply renal function cutoffs 1, 6

• CrCl ≥60 mL/min → TDF/FTC is first-line for all populations
• CrCl 30-60 mL/min in MSM with bone concerns → TAF/FTC is acceptable
• CrCl <30 mL/min → Neither TDF nor TAF-based PrEP is recommended

Step 3: Consider exposure type 3

• Receptive vaginal sex or injection drug use → TDF/FTC only (TAF/FTC lacks validation)
• Receptive anal sex in MSM → Either TDF/FTC or TAF/FTC (if renal/bone concerns exist)

Step 4: Monitor appropriately 2, 6

• Standard monitoring: Creatinine every 6 months for low-risk patients
• Enhanced monitoring: Creatinine every 3 months for patients with renal risk factors (CrCl 60-89 mL/min, diabetes, hypertension, age >50)

Common Pitfalls to Avoid

• Do not extrapolate treatment data to prevention: The fact that Biktarvy is effective and well-tolerated for HIV treatment does not mean it prevents HIV acquisition in uninfected individuals. 1, 2
• Do not use TAF/FTC for women with vaginal exposures: TAF/FTC lacks efficacy data for receptive vaginal sex, as tenofovir alafenamide achieves lower concentrations in vaginal tissue. 1, 3
• Do not prescribe PrEP without baseline testing: HIV antibody/antigen testing, renal function, hepatitis B surface antigen, and STI screening are mandatory before initiation. 2
• Do not abruptly discontinue in HBsAg-positive patients: Both TDF and TAF-based regimens treat hepatitis B; stopping can cause acute hepatitis flares or hepatic decompensation. 2, 6

Special Considerations for Hepatitis B Co-infection

• Measure hepatitis B surface antigen before PrEP initiation. 6
• For HBsAg-positive individuals, consider indefinite continuation or transition to hepatitis B treatment if PrEP is stopped, with close ALT/AST monitoring. 2, 6
• This applies to both TDF/FTC and TAF/FTC regimens, as both have anti-HBV activity. 2