Clinical Medicine Insights: Therapeutics

Treatment for hepatitis B (HBV), a global disease affecting over 400 million persons, has changed over the past 15 years. Many of the current treatments are oral therapies which suppress HBV viral load and improve liver-related outcomes. However, differences exist in the currently available therapies both in terms of potency and resistance. The newest HBV nucleotide to be approved for the treatment of hepatitis B is tenofovir disoproxil fumarate that when phosphorylated to its active form leads to DNA chain termination. Tenofovir is active against human immunodeficiency virus (HIV) and was approved for its treatment in 2001. It is also active against HBV and was approved for its treatment in 2008. Tenofovir has emerged as an effective and potent therapy against lamivudine resistant strains as well as wild type HBV. Tenofovir resistance to HBV is rare. Long-term use of tenofovir has been associated with renal and bone marrow toxicity in some HIV-infected patients. To date, this is the only oral therapy which is both potent and does not lead to viral resistance in both treatment naïve and experienced patients. Further studies in HBV mono-infected persons are needed to evaluate long-term impact of tenofovir use.