Initial ART Therapy for Treatment-Naïve Adults
For treatment-naïve adults without known resistance, hepatitis B co-infection, or severe renal impairment, start with an integrase strand transfer inhibitor (INSTI)-based regimen: either bictegravir/tenofovir alafenamide/emtricitabine (BIC/TAF/FTC) or dolutegravir plus tenofovir alafenamide/emtricitabine (DTG + TAF/FTC). 1
Recommended First-Line Regimens
The 2024 IAS-USA guidelines prioritize INSTI-based three-drug regimens as the standard of care:
Primary Options:
- BIC/TAF/FTC (single-tablet regimen) 1
- DTG + TAF/FTC (or DTG + TDF/emtricitabine if TAF unavailable) 1
Both regimens demonstrate:
- High barrier to resistance
- Once-daily dosing
- Minimal drug interactions
- Can be taken with or without food
- Superior virologic efficacy in comparative trials 2
Alternative INSTI-Based Regimens:
If the above are unavailable or contraindicated, consider:
- Dolutegravir + abacavir/lamivudine (requires HLA-B*5701 testing first) 1
- Elvitegravir/cobicistat/TAF/FTC 1
- Raltegravir + TAF/FTC 1
When NOT to Use Certain Regimens
Avoid DTG/3TC (two-drug regimen) for initial therapy if:
- HIV RNA >500,000 copies/mL
- Hepatitis B co-infection present
- Lamivudine resistance detected
- Pregnancy
- CD4 count <200/μL (limited data) 1
Critical point: DTG/3TC requires baseline laboratory results before initiation, making it unsuitable for rapid-start scenarios 3.
Alternative Class Options
If INSTIs cannot be used:
Boosted Protease Inhibitor-Based:
Use boosted darunavir when INSTI resistance is suspected (particularly after long-acting cabotegravir PrEP exposure) before resistance testing returns 1.
NNRTI-Based (less preferred):
- Doravirine + TAF/FTC 1
- Efavirenz-based regimens (older option with more side effects)
Nucleoside Backbone Considerations
Tenofovir alafenamide (TAF) is preferred over tenofovir disoproxil fumarate (TDF) for most patients due to:
- Lower renal toxicity risk
- Better bone safety profile
- Equivalent efficacy 3
However, TDF remains acceptable when TAF is unavailable or cost-prohibitive 1.
Emtricitabine and lamivudine are interchangeable as the second nucleoside component 1.
Key Implementation Points
Before Starting Therapy:
- Confirm HIV diagnosis with viral load
- Check baseline resistance testing (if time permits)
- Screen for hepatitis B surface antigen
- Assess renal function (creatinine clearance)
- HLA-B*5701 testing if considering abacavir 1
Monitoring After Initiation:
- HIV viral load at 1 month after starting 3
- Goal: undetectable viral load (<50 copies/mL) by 12-24 weeks
- CD4 count monitoring
- Assess adherence and tolerability
Common Pitfalls to Avoid
Do not use monotherapy with boosted protease inhibitors or dolutegravir—always use combination therapy 3
Do not add a single active agent to a failing regimen 3
Do not delay treatment waiting for resistance testing in most cases—start empiric therapy and adjust if needed 1
Review drug interactions carefully, especially with TAF dosing requirements 3
For pregnant patients or those planning pregnancy: Use DTG + TAF/FTC as first choice, or BIC/TAF/FTC as alternative 1
Strength of Evidence
The INSTI-based recommendations carry the highest evidence ratings (AIa) from the most recent 2024 IAS-USA guidelines 1, representing randomized controlled trial data with clear clinical benefit. These regimens have demonstrated superior efficacy, tolerability, and resistance profiles compared to older protease inhibitor and NNRTI-based options in head-to-head trials 2.