Key Points

• The HIV treatment medication Biktarvy (bictegravir, emtricitabine and tenofovir alafenamide) does not list weight gain as a side effect in the product labeling.
• However, a large meta-analysis study, as well as other research, suggests some new HIV treatments, including integrase strand inhibitors such as bictegravir, can be linked to significant weight gain.
• The exact mechanisms by which Biktarvy may lead to weight gain are not known. Weight gain with bictegravir may be due to a variety of reasons, such as a return to better health, an increased appetite in people living with HIV, or less nausea and stomach side effects.

Weight gain is common in patients initiated on antiretroviral treatment (ART). HIV disease can lead to weight loss and demands on energy, so halting HIV replication can lower metabolic needs and lead to weight gain if caloric intake remains the same or increases.

However, some recent studies have suggested that some treatments, including integrase strand inhibitors (INSTIs) such as bictegravir, dolutegravir or elvitegravir may be associated with weight gain in HIV patients.

What do studies say about weight gain with Biktary?

A large, 2019 meta-analysis of randomised trials published in Clinical Infectious Diseases found that some newer antiretroviral therapies (ART), including the integrase strand inhibitor (INSTI) bictegravir, appear to be linked with weight gain, as do newer studies of ART in general.

Investigators looked for an association between demographic factors, ART, disease characteristics and weight gain in previously untreated people living with HIV. The group included over 5,600 patients who received treatment between 2003 and 2015.

Drugs evaluated in the study included:

• tenofovir disoproxil fumarate (TDF) in combination with emtricitabine and or the newer formulation tenofovir alafenamide (TAF)
• efavirenz
• INSTIs such as dolutegravir, elvitegravir and bictegravir
• atazanavir and ritonavir
• rilpivirine

In the pooled analysis of all treatments, each study group showed some weight gain. The overall median weight gain of 2 kg (4.4 lbs) occurred primarily in the first year of treatment (48 weeks) in 12.8% of treatment-naive patients (never treated with HIV medications). Over a 2 year period, 17.3% of participants gained weight but 30.2% had weight loss.

Statistically significant risk factors linked to weight gain (over 48 weeks) included:

• Lower baseline CD4 cell count. CD4 count below 200 was the strongest risk factor for a weight gain of at least 10% of baseline weight (median gain of 2.97 kg or 6.5 kg).
• No injection drug use.
• Lower baseline weight or body mass index (BMI).
• Presenting with HIV/AIDS symptoms at baseline (gain of roughly 0.5 kg).
• Race (black) and sex (female), with black women being at highest risk of weight gain.

Biktarvy Weight Gain

Bictegravir, a component of Biktarvy, was associated with weight gain in this analysis, as were other integrase inhibitors. INSTI use was linked with more weight gain than were protease inhibitors or nonnucleoside reverse transcriptase inhibitors (NNRTIs).

• Dolutegravir and bictegravir were associated with more weight gain than elvitegravir and cobicistat.
• Patients on integrase inhibitors gained significantly more weight (3.24 kg or 7.1 lbs) than people taking either an NNRTI or a protease inhibitor.

Participants taking bictegravir or dolutegravir demonstrated similar weight gain. A significant risk of weight gain of more than 10% from baseline was seen with both bictegravir or dolutegravir.

Weight Gain: Integrase Strand Inhibitors (INSTI)