What is the recommended treatment regimen for HIV-1 infection using Descovy (emtricitabine and tenofovir alafenamide)?

Descovy for HIV-1 Treatment

Descovy (emtricitabine/tenofovir alafenamide) is not used as a standalone treatment for HIV-1 infection but serves as the nucleoside reverse transcriptase inhibitor (NRTI) backbone that must be combined with an integrase strand transfer inhibitor (InSTI) or boosted protease inhibitor to form a complete antiretroviral regimen. 1

Recommended Complete Regimens Using Descovy

First-Line Preferred Regimens

For treatment-naïve adults and adolescents, combine Descovy with an InSTI:

• Bictegravir/tenofovir alafenamide/emtricitabine (single-tablet regimen) - This is the preferred first-line option for most patients due to high efficacy, favorable side effect profile, and high barrier to resistance 1
• Dolutegravir plus Descovy - Highly effective combination with strong resistance profile 2, 1
• Elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (single-tablet regimen) - Rated AIa by international guidelines 2
• Raltegravir plus Descovy - Effective option with fewest drug interactions 2

Alternative Regimens When InSTIs Cannot Be Used

Boosted protease inhibitor plus Descovy:

• Darunavir (boosted with ritonavir or cobicistat) plus Descovy - Recommended when InSTI resistance is suspected, particularly after exposure to long-acting cabotegravir as PrEP 1, 3
• This combination has a high genetic barrier to resistance and maintains activity even with NRTI resistance 3, 4

Dosing

• Standard dose: Emtricitabine 200 mg/tenofovir alafenamide 25 mg once daily 2
• Must be taken with food when combined with elvitegravir/cobicistat 2
• Can be taken with or without food when combined with dolutegravir or raltegravir 2

Special Populations

Pregnant Women

• Dolutegravir plus Descovy is the preferred regimen 1
• Bictegravir/tenofovir alafenamide/emtricitabine is an acceptable alternative 1

Renal Impairment

• Descovy (tenofovir alafenamide) is strongly preferred over tenofovir disoproxil fumarate in patients with renal impairment 1, 3
• Tenofovir alafenamide has significantly fewer renal and bone toxicities compared to tenofovir disoproxil fumarate, especially when used with pharmacological boosters 3, 4, 5
• Can be used in patients with estimated creatinine clearance ≥30 mL/min 5

Hepatitis B Co-infection

• Patients with HIV/HBV co-infection must continue Descovy (or tenofovir disoproxil fumarate) to maintain HBV suppression 2, 1
• Do not use dolutegravir/lamivudine two-drug regimen in HBV co-infection 1

Osteoporosis or Bone Disease

• Descovy is preferred over tenofovir disoproxil fumarate in patients with established osteopenia or osteoporosis 2, 1

Critical Contraindications and Precautions

When NOT to Use Descovy Alone

• Never use Descovy as monotherapy - it must always be combined with at least one other active antiretroviral agent from a different class 1, 6

Drug Resistance Considerations

• Perform resistance testing before initiating therapy 2, 1, 6
• If multiple NRTI resistance mutations are present, boosted darunavir plus Descovy is preferred over InSTI-based regimens 3
• The presence of M184V/I mutation may reduce emtricitabine activity but does not preclude use of the regimen 4

Drug Interactions

• Cobicistat-boosted regimens have more drug interactions than unboosted regimens 1
• Rifampin cannot be used with bictegravir/tenofovir alafenamide/emtricitabine or elvitegravir/cobicistat combinations 1
• Check drug interactions at https://www.hiv-druginteractions.org/ before prescribing 2

Monitoring After Initiation

• Measure HIV RNA at 4-6 weeks after starting therapy to assess initial response 1, 3
• Monitor every 3 months until viral suppression (<50 copies/mL) is maintained for at least 1 year 1
• After 1 year of suppression, reduce monitoring to every 6 months 1
• Monitor renal function (serum creatinine, estimated GFR) at baseline and periodically 2
• Assess bone mineral density in patients at risk for osteoporosis 2

Common Pitfalls to Avoid

• Do not prescribe Descovy without a third agent - it is only the NRTI backbone, not a complete regimen 1, 6
• Do not delay treatment initiation - start ART as soon as possible after diagnosis to reduce morbidity and mortality 1, 6
• Do not overlook HBV co-infection status - stopping tenofovir-containing regimens in HBV co-infected patients can cause hepatitis flares 2, 1
• Do not ignore drug interactions, particularly with cobicistat-boosted regimens or rifampin 2, 1
• Do not use two-drug regimens (dolutegravir/lamivudine) if HIV RNA >500,000 copies/mL, lamivudine resistance present, or HBV co-infection exists 1

Postexposure Prophylaxis (PEP)

For nonoccupational HIV exposure in adults and adolescents ≥12 years:

• Preferred: Bictegravir/emtricitabine/tenofovir alafenamide 2
• Alternative: Dolutegravir plus Descovy 2
• Duration: 28 days 2