Reviewed by: HU Medical Review Board | Last reviewed: March 2023 | Last updated: June 2023
Biktarvy is a combination medication that contains bictegravir, emtricitabine, and tenofovir alafenamide (TAF). It is used as a standalone antiretroviral therapy (ART) regimen for HIV-1 in adults and children who weigh at least 14 kilograms and who have never taken any other HIV medicines before. Biktarvy may also be used in individuals who are replacing a stable ART regimen, have not had any previous treatment failures, and who have had a viral load of 50 copies per mL or less.
Although it is not a cure for HIV, when taken as directed, it allows for the virus to be suppressed. This prevents further transmission of HIV and allows an individual’s immune system to improve through increasing CD4 cell counts and decreasing the amount of active virus in the blood (viral load).
What are the ingredients in Biktarvy?
The main ingredients in Biktarvy are bictegravir, emtricitabine, and TAF. Emtricitabine and TAF are nucleoside reverse transcriptase inhibitors (NRTIs), while bictegravir is an integrase strand transfer inhibitor (INSTI, also known as an integrase inhibitor).
How does Biktarvy work?
Biktarvy is a combination of two NRTI medications and one integrase inhibitor. NRTIs stop the reverse transcription step of the HIV life cycle. Normally, HIV uses its reverse transcriptase enzyme to build a strand of DNA from its original RNA form. In order to do this, it uses genetic building blocks called nucleosides that come from the host cell. These nucleosides are strung together one at a time, like beads on a string, to create the final DNA product.
NRTIs act as nucleoside mimics that stop the DNA-building process. NRTIs look like normal nucleosides, except they’re missing a special chemical group on one side. Without this group, the reverse transcriptase enzyme is unable to attach more nucleosides to the chain after them. This prevents the full string of DNA from being formed, preventing HIV RNA from making it all the way through the reverse transcription process.
How do integrase inhibitors treat HIV?
After HIV RNA is reverse transcribed into newly-formed DNA, it gets integrated into the host cell DNA using an enzyme called integrase. This allows HIV to be actively replicated with the rest of our DNA as our cell carries out its normal functions. Integrase inhibitors can be used to block the integrase enzyme and prevent the integration of HIV DNA into our host cells. If HIV’s DNA cannot be inserted into our host cells’ genome, the virus cannot continue to be replicated, assembled into mature virus particles, and released into the blood to continue infecting other cells.
What are the possible side effects of Biktarvy?
The most common side effects of Biktarvy include, but are not limited to:
These are not all the possible side effects of Biktarvy. Talk to your doctor about what to expect when taking Biktarvy. You also should call your doctor if you have any changes that concern you when taking Biktarvy.
Things to note
Biktarvy has a boxed warning, the strictest warning from the US Food and Drug Administration (FDA). It has this warning because of the possibility of serious side effects as described below.
As with any medication, there are several very rare but serious risks that need to be considered before taking Biktarvy. Your healthcare provider can help determine what issues you may be at risk for and help determine what treatment options are the safest for you. It’s also important to remember that the risk of one or more of these issues occurring is low, and the benefits of treating the virus often greatly outweigh the risks.
Several of these rare but serious side effects of Biktarvy include liver issues and an increase of lactic acid in the blood (lactic acidosis). Signs of liver issues include:
- Dark-colored urine
- Loss of appetite
- Yellowing of the whites of the eyes or skin
- Light-colored bowel movements
- Pain or tenderness on the right side of your stomach
Signs of lactic acidosis include:
- Trouble breathing
- Feeling cold, especially in the limbs
- Dizziness or lightheadedness
- Feeling tired or weak
- Muscle pain
- Nausea and vomiting
- Irregular or fast heartbeat
These are not all the possible side effects of Biktarvy. Patients should talk to their doctor about what to expect with treatment with Biktarvy. If you have hepatitis B virus and start taking Biktarvy, your hepatitis B may get worse. Biktarvy may also cause new or worsening kidney issues. This includes an increased risk of kidney failure. Your healthcare provider will need to monitor your kidney function before you start and while taking Biktarvy.
Before starting Biktarvy, tell your doctor if you:
- Have or previously had hepatitis B virus
- Have a history of liver or kidney problems
- Are pregnant or planning to become pregnant
- Are breastfeeding or planning to breastfeed
- Are taking any over-the-counter vitamins, supplements, medicines, or herbal remedies
- Are on any other medications or are about to start any other medications, including hormonal birth control or medications for hepatitis viruses
Some antiseizure drugs may reduce the concentration of Biktarvy in the body.
Individuals taking medications called dofetilide or rifampin should not take Biktarvy.
Biktarvy may cause a condition called IRIS (immune reconstitution inflammatory syndrome). IRIS occurs when an individual’s immune system gets stronger after being weak and responds aggressively to previously hidden infections. This heightened response may make the person fighting the infection feel worse. Alert your healthcare provider immediately if you begin to have new symptoms after taking Biktarvy.
TAF can decrease bone mineral density (BMD) after 48 weeks of treatment. But TAF does not lower BMD as much as tenofovir disoproxil fumarate (TDF) does. TAF is also less likely than TDF to harm your kidneys. They have similar antiviral effectiveness. TAF is more likely to cause dyslipidemia compared to TDF. Whenever possible, TAF is the preferred choice over TDF. It is important not to use the 2 drugs at the same time.