Canadian Health Officials Warn against Use of Tebivudine (Tyzeka/Sebivo) in Combination with Interferons

Officials with Health Canada issued a warning last week that the recently approved anti-HBV drug telbivudine (marketed as Tyzeka in the U.S. and as Sebivo elsewhere) should not be used in combination with any type of interferon due to the risk of additive side effects. Conventional interferon alfa-2b (Intron-A) and pegylated interferon alfa-2a (Pegasys) are currently approved as treatments for chronic hepatitis B.

Below is a report from the Canadian Press describing the recent announcement:

Taking hepatitis B drug with interferon potentially dangerous: Health Canada

Health Canada is warning consumers being treated with telbivudine (Tyzeka/Sebivo) for hepatitis B not to combine the medication with any interferon products because of potentially serious drug interactions.

Taking both telbivudine and interferon may increase the risk of peripheral neuropathy, a potentially serious condition characterized by weakness, numbness, tingling and burning sensations in the arms and/or legs.

Telbivudine is authorized by Health Canada and by the FDA in the U.S. for use as monotherapy, not for use in combination with any interferon products, including standard or pegylated types of interferon alfa (e.g., Pegasys, PegIntron, Intron A, Roferon A, and Infergen) and of interferon beta (marketed under brand names such as Rebif, Betaseron, and Avonex).

The drug's manufacturer, Novartis Pharmaceuticals Canada Inc., said that in a small clinical trial testing the use of both telbivudine and Pegasys (peginterferon alfa-2a), serious peripheral neuropathy occurred in five out of 48 patients (10 percent), and was occasionally disabling. The condition usually started about three months after initiation of treatment.

Health Canada said Wednesday it is not yet known if this adverse event is reversible once treatment is stopped, or whether it might also occur when the drug is used with interferon products other than Pegasys.

Consumers are advised to tell their doctors if they are taking telbivudine and an interferon product, but should not discontinue or modify telbivudine without first consulting their physician, due to the risk of worsening the hepatitis B infection.

Peripheral neuropathy has been reported in five out of 2,000 patients (less than one percent) using telbivudine alone in clinical trials. The disorder also is a common adverse side effect of Pegasys (reported on average in one to five out of 100 patients in clinical trials).

Consumer information for telbivudine is being updated and Novartis has issued a letter to health professionals advising them of the new safety information.



Canadian Press (via Yahoo News). Taking hepatitis B drug with interferon potentially dangerous: Health Canada. March 12, 2008.