Antiviral Drug Side Effects May Trigger Other Types of Hepatitis, European Regulators Warn

Certain antiviral drugs used to treat hepatitis C may cause a reactivation of hepatitis B, according to new warnings issued by European health officials. 

The European Medicines Agency’s Pharmacovigilance Risk Assessment Committee (PRAC) issued a warning on December 2, indicating patients who take direct-acting antivirals to treat hepatitis C may face an increased risk of reactivating latent hepatitis B.

Health officials warned patients who had hepatitis B in the past and are now taking certain direct-acting antivirals to treat hepatitis C infection are at risk of having the hepatitis B virus reactivate.

So far, at least 30 cases of hepatitis B reactivation have been reported in Europe. The direct-acting antiviral drugs are marketed in the European Union as Daklinza, Exviera, Harvoni, Olysio, Sovaldi, and Viekirax.

The announcement follows an FDA advisory issued in October, which indicated that a black box warning would be added to hepatitis C direct-acting antivirals in the U.S. The FDA warned that the drugs could reactivate hepatitis B in patients with both viruses, indicating that the agency had received at least 24 reports of hepatitis B reactivation after patients began using the drugs.

The antiviral medications are used to treat chronic long-term hepatitis C; an inflammation of the liver caused by the hepatitis C virus, at times also caused by drug or alcohol abuse, infections or autoimmune disease. The drugs help to control and sometimes cure the hepatitis C virus, preventing liver problems like cancer, cirrhosis and death.

Data also indicates there is a lack of evidence suggesting the direct-acting antivirals can treat liver cancer in patients. The agency said it concluded “further studies should be carried out before firm conclusions can be draw” pertaining to liver cancer treatment.

The agency suggests the rapid-treatment reducing the hepatitis C virus may re-trigger the hepatitis B virus, which can be fatal.

While reactivation frequency of hepatitis B is low, PRAC calls for a warning to be included in the mediation prescribing information. PRAC also announced a recommendation to forward its recommendations to the Committee for Medicinal Products for Human Use for a final decision.

The PRAC warning recommended hepatitis C infected patients should be screened for the hepatitis B virus before starting treatment with any direct-acting antivirals. Patients infected with both viruses should be monitored and current medical guidelines should be followed.