A recent clinical trial found that the adult antiviral drug, tenofovir
disoproxil fumarate (tenofovir DF), is safe and effective in treating
adolescents with hepatitis B virus (HBV). Trial results published in the
December issue of Hepatology,
a journal of the American Association for the Study of Liver Diseases
(AASLD), show that tenofovir DF suppressed HBV in 89% of pediatric
participants.
Chronic HBV is a major health burden that studies estimate affects 350
million people worldwide, with 600,000 deaths attributed to this chronic
disease. The Centers for Disease Control and Prevention (CDC) estimate
that more than one million Americans have chronic HBV, with most
patients infected during childhood. Medical evidence suggests that 90%
of patients infected as infants, and up to 50% infected between one and
four years of age develop chronic HBV; 25% of adults who become
chronically infected in childhood develop cirrhosis or liver cancer.
“Children chronically infected with HBV are at great risk of developing
severe liver disease and possible death due to complications from the
disease,” said Dr. Karen Murray, Chief of the Division of
Gastroenterology and Hepatology at Seattle Children’s Hospital in
Washington and lead researcher of the clinical trial. “Tenofovir DF is
highly effective in treating adults with chronic HBV and our trial
evaluated safety and efficacy of the drug in adolescents.”
This double-blind, placebo-controlled trial was conducted in 101
adolescents aged 12 to 17 years. Participants were randomized with 52
receiving a daily 300 mg dose of tenofovir DF and 54 taking a placebo
for 72 weeks. A virologic response—ability of the antiviral medication
to suppress the virus in participants—was the main outcome of this
clinical trial. At the onset of the trial 91% of participants tested
positive for the hepatitis B e-antigen and 85% received prior HBV
therapy.
Researchers observed a virologic response in 89% of participants who
received tenofovir DF, while none of the patients in the placebo group
achieved HBV suppression. The drug successfully suppressed HBV and
normalized alanine aminotransferase (ALT) levels in both adolescents who
received no prior treatment and in those previously exposed to HBV
therapy. No safety issues, such as a 6% reduction in spine bone density
(safety end point), were reported. Trial participants taking tenofovir
showed no resistance to the drug.
“Tenofovir DF therapy was well tolerated and effective in suppressing
HBV in adolescents,” concludes Dr. Murray. “Our trial demonstrates that
tenofovir is a beneficial therapy for managing chronic HBV in teens.”
The authors note that a two-year open-label phase study will further
investigate the sustained response and safety of tenofovir DF.
In an editorial also published in Hepatology, Dr. Philip Rosenthal with
the University of California, San Francisco (UCSF) questions what can be
done to alter the development of liver disease and liver cancer in
children with chronic hepatitis B infection. “It was not long ago that
drugs to treat HBV were limited and it is gratifying to see an increase
in medications to combat this disease being approved for use in children
and teens,” said Dr. Rosenthal. “While the study by Murray et al. was
limited to adolescents, future study of tenofovir DF in younger children
is underway.”
