A 45-year-old man with chronic hepatitis B (HBeAg positive, HBV DNA 200,000 IU/mL, ALT 2.5 × ULN, liver biopsy showing METAVIR A2F2) is started on tenofovir disoproxil fumarate. After 48 weeks of therapy, he remains HBeAg positive with HBV DNA 4 log10 IU/mL. How is this treatment response best classified?
- A Complete response
- B Partial virological response ✓
- C Primary non-response
- D Virological breakthrough
Correct answer: B. Partial virological response
Explanation
Partial virological response in chronic hepatitis B is defined as a decrease in HBV DNA by > 1 log10 IU/mL from baseline but with detectable HBV DNA at 24 weeks (for interferon) or 48 weeks (for nucleos(t)ide analogues). Complete response requires undetectable HBV DNA. Primary non-response is < 1 log10 decrease at 12 weeks of therapy. Virological breakthrough is a increase in HBV DNA by > 1 log10 from nadir during continued therapy, usually indicating resistance or non-adherence. TDF resistance is extremely rare.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.