EU health regulator warns some hep C drugs could reactivate hep B

The European Medicines Agency warned that some of the most successful hepatitis C treatments on the market could reactivate hepatitis B in patients, the second time this year it has raised safety concerns over these treatments.

The latest health warning covers some of the top-selling products in the multi-billion dollar hepatitis C market, including Sovaldi, Exviera, Viekirax, Olysio and Daklinza.

These drugs cure well over 90 percent of patients with the liver disease and also cuts down the duration of the treatment.

The Pharmacovigilance Risk Assessment Committee (PRAC), part of the EMA, said it suspected the reactivation of the hepatitis B virus was due to the rapid reduction of the hepatitis C virus, which is known to suppress the hepatitis B virus.

The agency recommended that patients be screened to ensure they are not infected with both the viruses before being treated for hepatitis C.

It also recommended that a warning be included in the label for these medicines.

The U.S. Food and Drug Administration had issued a similar warning in October, with similar recommendations.

The latest warning from the EMA follows one in April when it said that data showed that patients taking hepatitis C drugs were at risk of their liver cancer returning.

However, the PRAC said on Friday that further studies were needed before firm conclusions could be drawn.

Gilead Sciences Inc makes Sovaldi. AbbVie Inc makes Exviera and Viekirax. Johnson & Johnson makes Olysio and Bristol-Myers Squibb makes Daklinza.

The shares of the four drugmakers were up between 0.1 percent and 0.7 percent on Friday afternoon, roughly in line with the broader health index's 0.5 percent increase.