Low-dose tenofovir is more potent than adefovir and is effective in controlling HBV viremia in chronic HBeAg-negative hepatitis B.
OBJECTIVE
To study the efficacy of tenofovir disoproxil fumarate (TDF) at low dose in a small open trial of chronic hepatitis B patients with advanced stage disease.


METHODS
Eleven patients were treated with TDF 75 mg for a median period of 80 (range, 24-576) wk and then 7 cases were shifted to an adefovir 10 mg treatment group. All patients had been pre-treated with lamivudine: 5 had YMDD resistant mutants and 6 wild-type virus. When TDF was started, 4 patients had low-level viremia and 6 were PCR-negative.


RESULTS
During TDF treatment, PCR remained negative in 10 patients, transaminase levels were normal and no significant viral breakthrough was observed. The drug was well tolerated in all cases. When TDF 75 mg was substituted with adefovir 10 mg, 3 out of 7 patients had a persistent viral rebound (2700-130,000 copies/mL), in whom lamivudine had to be reintroduced.


CONCLUSIONS
Low-dose TDF monotherapy can control HBV viremia for an extended period of time without the emergence of resistance and is more potent than adefovir at the standard dosage. The use of a reduced dose of TDF could diminish the cost of therapy in low-income countries, but further studies in a larger population and in HBeAg-positive subjects are needed.
Del Poggio
Paolo
P
Hepatology Unit, Treviglio Hospital, Piazza Ospedale 1, 24047 Treviglio (Bg), Italy. pdpoggio@ospedale.treviglio.bg.it
Zaccanelli
Maurizio
M
Oggionni
Maria
M
Colombo
Silvia
S
Jamoletti
Carlo
C
Puhalo
Vesna
V
D000225:Adenine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D024882:Drug Resistance, Viral; D005260:Female; D006509:Hepatitis B / Q000188:drug therapy* / Q000276:immunology*; D006513:Hepatitis B e Antigens / Q000378:metabolism*; D006515:Hepatitis B virus / Q000187:drug effects / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D063065:Organophosphonates / Q000627:therapeutic use*; D000068698:Tenofovir; D014766:Viremia / Q000188:drug therapy* / Q000276:immunology
D000998:Antiviral Agents; D006513:Hepatitis B e Antigens; D063065:Organophosphonates; C053001:adefovir; D000068698:Tenofovir; D000225:Adenine
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