Can Truvada (emtricitabine and tenofovir disoproxil fumarate) be used for prophylaxis against Hepatitis B Virus (HBV) or only for suppression of HBV replication?

Truvada for HBV: Suppression, Not Primary Prophylaxis

Truvada (tenofovir disoproxil fumarate/emtricitabine) is FDA-approved for treatment and suppression of chronic HBV infection, not for primary prophylaxis against acquiring HBV in uninfected individuals. 1

FDA-Approved Indication

• Tenofovir disoproxil fumarate is indicated for the treatment of chronic hepatitis B virus (HBV) in adults and pediatric patients 12 years of age and older, meaning it suppresses active infection rather than prevents initial acquisition 1
• The dosage for HBV treatment is identical to HIV treatment: 300 mg once daily in adults and weight-based dosing in pediatric patients 1

Distinction Between Suppression and Prophylaxis

Viral Suppression (What Truvada Does for HBV):

• Tenofovir blocks HBV replication in liver cells and suppresses viral replication to the lowest possible level to halt liver disease progression 2
• HBV infection cannot be eradicated fully because covalently closed circular DNA (cccDNA) persists in hepatocyte nuclei, so treatment aims for sustained suppression 3
• Tenofovir has demonstrated superior antiviral efficacy compared to adefovir and should be considered first-line monotherapy for HBV-monoinfected patients 2

Primary Prophylaxis (What Truvada Does NOT Do for HBV):

• True prophylaxis against HBV acquisition in uninfected individuals is achieved through HBV vaccination, not antiviral medications 3
• Vaccination should be strongly considered in HBV-naïve patients (negative for HBsAg, HBsAb, and HBcAb) 3

Special Context: Reactivation Prophylaxis

There is one important exception where Truvada functions as "prophylaxis" - preventing HBV reactivation in patients with prior HBV exposure undergoing immunosuppressive therapy:

• Prophylactic antiviral therapy is recommended for HBsAg-positive patients undergoing immunosuppressive therapy (such as rituximab-containing regimens for lymphoma) 3
• Tenofovir may be the preferred agent in this setting due to superior antiviral efficacy and lower resistance rates compared to lamivudine, though limited data exist in cancer patients 3
• Antiviral prophylaxis should continue for at least 6-12 months after the last dose of immunosuppressive therapy 3

HIV/HBV Co-infection Considerations

• In HIV/HBV co-infected patients, Truvada is a preferred agent because both tenofovir and emtricitabine have anti-HBV activity while simultaneously treating HIV 2, 4
• Truvada alone should never be used in patients with HIV-1 infection, as it would constitute inadequate HIV therapy and risk resistance development 1

Critical Warning: Discontinuation Risk

• Severe acute exacerbations of hepatitis B have been reported in HBV-infected patients who discontinue anti-hepatitis B therapy, including tenofovir 1
• Hepatic function must be monitored closely with clinical and laboratory follow-up for at least several months after discontinuation 1
• Resumption of anti-hepatitis B therapy may be warranted if flare occurs 1

Bottom Line Algorithm

For HBV-naïve individuals: Use HBV vaccination for prophylaxis, not Truvada 3

For chronic HBV infection: Use Truvada for viral suppression as treatment 1, 2

For prior HBV exposure + immunosuppression: Use tenofovir-based prophylaxis to prevent reactivation 3

For HIV/HBV co-infection: Use Truvada as part of complete antiretroviral regimen for dual suppression 2, 4