What is Genvoya (elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide)?

What is Genvoya?

Genvoya is a single-tablet, once-daily antiretroviral medication containing four components: elvitegravir 150 mg (an integrase strand transfer inhibitor), cobicistat 150 mg (a CYP3A inhibitor that boosts elvitegravir levels), emtricitabine 200 mg, and tenofovir alafenamide 10 mg (both nucleoside reverse transcriptase inhibitors), used as a complete regimen for treating HIV-1 infection. 1

Drug Components and Mechanism

Genvoya combines four antiretroviral agents in a fixed-dose formulation 1:

• Elvitegravir (EVG): An HIV-1 integrase strand transfer inhibitor that blocks viral DNA integration into host cell DNA
• Cobicistat (COBI): A pharmacokinetic enhancer that inhibits CYP3A enzymes, allowing once-daily elvitegravir dosing
• Emtricitabine (FTC): A nucleoside analog reverse transcriptase inhibitor
• Tenofovir alafenamide (TAF): A novel prodrug of tenofovir with improved pharmacology compared to tenofovir disoproxil fumarate (TDF)

FDA-Approved Indications

Genvoya is indicated for 1:

• Treatment-naive adults and children (weighing ≥25 kg) with HIV-1 infection
• Virologically suppressed patients (HIV-1 RNA <50 copies/mL for ≥6 months) switching from another regimen, with no history of treatment failure and no known resistance mutations to Genvoya's components

Administration and Dosing

• One tablet once daily with food 1
• Must be taken with food to optimize absorption (particularly important for elvitegravir) 2, 3
• No dose adjustment needed for mild-to-moderate hepatic impairment (Child-Pugh A or B) 1
• Not recommended for severe hepatic impairment (Child-Pugh C) 1

Position in Current Guidelines

While Genvoya was previously a recommended initial regimen, current 2020 guidelines favor other integrase inhibitor-based regimens over elvitegravir-containing combinations 4. Specifically:

• Dolutegravir and bictegravir are preferred over elvitegravir due to higher barriers to resistance, fewer drug interactions, and no food requirement 4
• Elvitegravir is the least-favored integrase inhibitor because cobicistat (a potent CYP3A4 inhibitor) causes more drug interactions than other integrase inhibitors 4

Key Advantages

Tenofovir alafenamide (TAF) offers significant safety benefits over older tenofovir formulations 5, 6:

• 90% lower plasma tenofovir exposure compared to TDF, while maintaining higher intracellular active metabolite concentrations 7
• Reduced bone mineral density loss: Significantly less hip and spine bone density reduction compared to TDF-containing regimens 8
• Improved renal safety: Lower rates of proteinuria, albuminuria, and tubular proteinuria 8, 5
• Single-tablet regimen: Simplifies adherence with once-daily dosing 5

Important Disadvantages and Warnings

Cobicistat creates substantial drug interaction risks 2, 3:

• Raises serum creatinine by 0.1-0.15 mg/dL through inhibition of tubular secretion (not actual kidney damage) 2
• Extensive CYP3A4-mediated drug interactions 4
• Contraindicated with simvastatin and lovastatin due to severe rhabdomyolysis risk 9, 10
• Should be avoided in pregnancy due to inadequate plasma levels 2

Additional limitations 2, 3:

• Lower barrier to resistance compared to dolutegravir and bictegravir
• Cannot be used with rifampin (tuberculosis treatment)
• Must be taken with food
• More expensive than generic alternatives

Critical Drug Interactions

Avoid or use extreme caution with 11, 9:

• Statins: Contraindicated with simvastatin/lovastatin; use rosuvastatin or pravastatin with careful monitoring
• Acid-reducing agents: Proton pump inhibitors and H2-blockers decrease elvitegravir absorption
• Tenofovir-boosting combinations: When combined with other boosted antiretrovirals (ritonavir/cobicistat-containing regimens), tenofovir levels increase significantly, requiring frequent renal monitoring 11

Safety Profile

Common adverse events include 8:

• Diarrhea
• Nausea
• Headache

Serious toxicity in overdose has been reported, including distributive shock, respiratory failure, metabolic acidosis, and cardiac dysfunction, though this is rare 12, 13.

Clinical Efficacy

Genvoya demonstrates 8, 5:

• Non-inferior virologic suppression (<50 copies/mL at 48 weeks) compared to TDF-containing regimens in treatment-naive patients
• 96% maintained virologic suppression when switching from other regimens in suppressed patients
• Effective in children ≥2 years weighing ≥14 kg 14

When to Consider Genvoya

Use Genvoya when 4, 2:

• Preferred integrase inhibitors (dolutegravir, bictegravir) are unavailable or contraindicated
• Patient has mild-to-moderate renal impairment (CrCl 30-50 mL/min) where TAF offers renal advantages over TDF
• Patient has osteoporosis or high fracture risk where TAF's bone safety profile is beneficial
• Switching virologically suppressed patients from older, more toxic regimens

Avoid Genvoya when:

• CrCl <30 mL/min 1
• Severe hepatic impairment 1
• Pregnancy 2
• Significant drug interaction risks (multiple CYP3A4 substrates)
• Rifampin therapy needed 3