FDA Hepatitis Update - Labeling changes to Tyzeka (telbivudine) 600 mg tablets and oral solution 100 mg/5 mL reflect risk of resistance-associated substitutions

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Title: FDA Hepatitis Update - Labeling changes to Tyzeka (telbivudine) 600 mg tablets and oral solution 100 mg/5 mL reflect risk of resistance-associated substitutions

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FDA has approved changes in product labeling for Tyzeka® (telbivudine) 600 mg tablets and Tyzeka® (telbivudine) oral solution 100 mg/5 mL related to a higher risk of developing resistance-associated substitutions in treated patients.

Indications and Usage-Under Section 1.1 Chronic Hepatitis B
The following points should be considered when initiating therapy with Tyzeka”:
• For HBeAg-positive patients, Tyzeka should only be initiated in patients with HBV DNA less than 9 log10 copies/mL and ALT greater than or equal to 2x Upper Limit of Normal (ULN) prior to treatment.
• For HBeAg-negative patients, Tyzeka should only be initiated in patients with HBV DNA less than 7 log10 copies/mL prior to treatment.
• On-treatment response should guide continued therapy [see Dosage and Administration (2.1) and Microbiology (12.4)].

Dosage and Administration-Under Section 2.1 Adults and Adolescents (16 years of age and older):
Due to higher rates of resistance that may develop with longer term treatment among patients with incomplete viral suppression, treatment should only be initiated, if pre-treatment HBV DNA and ALT measurements are known, in the following patient populations:

For HBeAg-positive patients, HBV DNA should be less than 9 log10 copies/mL and ALT should be greater than or equal to 2x ULN prior to treatment with Tyzeka.

 For HBeAg-negative patients, HBV DNA should be less than 7 log10 copies/mL prior to treatment with Tyzeka.

HBV DNA levels should be monitored at 24 weeks of treatment to assure complete viral suppression (HBV DNA less than 300 copies/mL). Alternate therapy should be initiated for patients who have detectable HBV DNA after 24 weeks of treatment. Optimal therapy should be guided by further resistance testing.

Dosage and Administration-Under Section 2.4-Duration of Therapy:
For patients with incomplete viral suppression (HBV DNA greater than or equal to 300 copies/mL) after 24 weeks of treatment, alternate therapy should be instituted. HBV DNA should be monitored every 6 months to assure continued response. If patients test positive for HBV DNA at any time after their initial response, alternate treatment should be instituted. Optimal therapy should be guided by resistance testing.

For more information on the role of Tyzeka in the treatment of of hepatitis, please see the American Association for the Study of Liver Diseases (AASLD) Practice Guidelines for Management of Chronic Hepatitis B

Richard Klein
Office of Special Health Issues
Food and Drug Administration

Kimberly Struble
Division of Antiviral Drug Products
Food and Drug Administration

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