Can a patient taking tenofovir (TDF) 50 mg daily, Prezista (darunavir) 800 mg daily, ritonavir (RTV) 100 mg daily, and zidovudine (AZT) 300 mg daily be switched to Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide) on the same day if there is no resistance?

Switching from Current ART Regimen to Biktarvy

Yes, a patient taking tenofovir 50 mg daily, darunavir 800 mg daily, ritonavir 100 mg daily, and zidovudine 300 mg daily can be safely switched to Biktarvy on the same day if there is no resistance. 1

Rationale for Switching

• Switching from a boosted protease inhibitor (PI) regimen to an integrase strand transfer inhibitor (InSTI) regimen like Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide) is appropriate for patients with virologic suppression and no history of resistance 1
• Biktarvy provides several advantages over the current regimen:
  • Single-tablet, once-daily dosing improves convenience and potentially adherence 1
  • Elimination of ritonavir-associated drug interactions and metabolic effects 2
  • Replacement of zidovudine, which is no longer recommended due to long-term toxicity concerns 1
  • Avoidance of potential renal and bone toxicity associated with tenofovir disoproxil fumarate (if the current tenofovir is TDF) 1

Prerequisites Before Switching

• Review of treatment history and results of prior resistance testing is mandatory before making any treatment changes 1
• Confirm that the patient has no history of:
  • InSTI resistance (particularly to bictegravir) 1
  • NRTI resistance (particularly to emtricitabine or tenofovir) 1
  • Virologic failure on previous regimens 1
• Verify current virologic suppression (HIV RNA <50 copies/mL) 1, 2

Switching Process

• The switch can be made on the same day without a lead-in period if there is no resistance 1, 2
• Discontinue all components of the previous regimen (tenofovir, darunavir, ritonavir, and zidovudine) and start Biktarvy (bictegravir 50 mg/emtricitabine 200 mg/tenofovir alafenamide 25 mg) once daily 1, 2
• Biktarvy should be taken with or without food 3

Monitoring After Switch

• Assess HIV viral load 1 month after switching regimens 1
• Continue monitoring viral load every 3 months for the first year after switching, then at least every 6 months thereafter if the patient remains stable 1
• Monitor for potential adverse effects, though Biktarvy is generally well-tolerated 2, 4

Special Considerations

• If the patient has hepatitis B virus (HBV) co-infection, Biktarvy is appropriate as it contains tenofovir alafenamide, which is active against HBV 1, 5
• If the patient has renal impairment, Biktarvy is generally preferred over regimens containing tenofovir disoproxil fumarate 1
• Biktarvy tablets should not be crushed for administration via feeding tubes, as this may result in decreased drug levels and potential virologic failure 6

Potential Pitfalls to Avoid

• Do not switch to Biktarvy if there is any history of resistance to integrase inhibitors or the NRTI components (emtricitabine or tenofovir) 1
• Do not switch without reviewing complete treatment history and resistance testing results 1
• Avoid switching if the patient is taking medications with significant drug interactions with Biktarvy 1
• Ensure the patient understands the importance of adherence to the new regimen to maintain virologic suppression 1

Evidence Supporting This Approach

• Clinical trials have demonstrated that switching from boosted PI regimens to Biktarvy maintains virologic suppression in >90% of patients at 48 weeks 2
• The 2024 International Antiviral Society-USA guidelines support switching from older regimens to recommended initial regimens like Biktarvy in virologically suppressed patients 1
• Same-day initiation of Biktarvy has been shown to be effective and well-tolerated in treatment-naïve patients, suggesting that immediate switching is also feasible 3