In the field of human immunodeficiency virus (HIV) treatment, the development and application of fixed-dose combination therapies have significantly improved treatment convenience and patient adherence. Biktarvy® (generic name: bictegravir/emtricitabine/tenofovir alafenamide tablets) is a well-established triple-drug antiretroviral regimen that, since its approval, has become an important option for the treatment of HIV-1 infection due to its potent antiviral efficacy, favorable safety profile, and simplified dosing regimen.

DengyueMed will provide a comprehensive overview of Biktarvy, including its basic information, mechanism of action, clinical applications, safety, and precautions for use.

Basic Drug Overview

Biktarvy is a fixed-dose combination developed by Gilead Sciences, containing three antiretroviral agents:

• Bictegravir (BIC)

• Emtricitabine (FTC)

• Tenofovir alafenamide (TAF)

It is an oral tablet available in two strengths:

• One formulation contains bictegravir 50 mg, emtricitabine 200 mg, and tenofovir alafenamide 25 mg

• The other contains bictegravir 30 mg, emtricitabine 120 mg, and tenofovir alafenamide 15 mg

These formulations are designed for patients of different body weight ranges.

In terms of regulatory approval, Biktarvy was first approved by the U.S. Food and Drug Administration (FDA) in July 2018 and by the European Union in June of the same year. It was approved in China by the National Medical Products Administration (NMPA) in August 2019. As a prescription medication, Biktarvy has been included in China’s National Reimbursement Drug List (Category B), helping to reduce the financial burden on patients.

Core Mechanism of Action: Triple Synergy to Block Viral Replication

The strong antiviral activity of Biktarvy results from the synergistic action of its three components, which block multiple key stages of the HIV-1 life cycle and comprehensively suppress viral replication.

Bictegravir is an integrase strand transfer inhibitor (INSTI). During HIV-1 replication, viral DNA must be integrated into the host cell genome by the viral integrase enzyme. Bictegravir selectively inhibits the strand transfer activity of HIV-1 integrase, preventing the integration of viral DNA into host DNA and thereby blocking viral replication at an early stage. It provides potent and durable viral suppression.

Emtricitabine and tenofovir alafenamide are nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs). These agents mimic natural nucleosides required for viral replication and are incorporated into the newly synthesized viral DNA during reverse transcription, leading to premature termination of DNA chain elongation and inhibition of viral replication.

Tenofovir alafenamide is an improved prodrug of tenofovir. Compared with earlier tenofovir formulations, TAF releases the active drug more slowly and more selectively within target cells, significantly reducing the risk of renal and bone toxicity and offering an improved safety profile.

Through the combined inhibition of integrase and reverse transcriptase, Biktarvy delivers enhanced antiviral efficacy while reducing the risk of resistance development.

Key Precautions and Considerations

1. Monitoring in Patients with Co-infections

Patients co-infected with HIV and hepatitis B virus (HBV) or hepatitis C virus (HCV) are at increased risk of severe hepatic adverse events during antiretroviral therapy. HBV infection status should be assessed before initiating treatment. In patients with HIV/HBV co-infection, discontinuation of Biktarvy may result in severe acute exacerbation of hepatitis; therefore, close clinical and laboratory monitoring is required for several months after treatment cessation.

2. Risk of Lactic Acidosis

The use of nucleoside analogues, either alone or in combination with other antiretroviral agents, has been associated with lactic acidosis and severe hepatomegaly with steatosis, which can be fatal. Treatment should be suspended immediately if clinical or laboratory findings suggest lactic acidosis or significant hepatotoxicity.

3. Drug Interactions

Biktarvy must not be co-administered with rifampin or St. John’s wort. Concomitant use with magnesium- or aluminum-containing antacids, iron supplements, sucralfate, rifabutin, rifapentine, atazanavir, boceprevir, and certain other agents is not recommended. If calcium supplements are required, they should be taken together with Biktarvy.

4. Prevention of HIV Transmission

Although effective viral suppression significantly reduces the risk of sexual transmission of HIV, residual risk cannot be completely eliminated. Patients should continue to follow national guidelines for HIV prevention.

5. Special Populations

Pregnant women should use Biktarvy at the recommended dosage; virologically suppressed pregnant patients may continue taking one tablet once daily. Patients who drive or operate machinery should exercise caution, as dizziness may occur.

Summary

As a triple-drug fixed-dose antiretroviral regimen, Biktarvy offers key advantages including potent antiviral efficacy, simplified once-daily dosing, and a favorable safety profile, making it a high-quality treatment option for adult patients with HIV-1 infection. Its synergistic mechanism of action helps reduce resistance risk, while the single-tablet regimen significantly improves treatment adherence. Inclusion in the national reimbursement system has further enhanced its accessibility.

It is important to emphasize that Biktarvy should be prescribed and monitored by physicians experienced in HIV management. Patients must strictly follow medical guidance, undergo regular monitoring, and remain vigilant for adverse effects and disease progression. With ongoing advances in medical research, Biktarvy is expected to continue playing a vital role in HIV treatment, offering patients the possibility of long-term survival and improved quality of life.