Drugmaker AbbVie said it expects a hepatitis C treatment to go on sale in the U.S. this year after completing testing for the liver disease drug.

AbbVie said its latest trial results show the therapy was able to clear the virus in a group of patients who are particularly difficult to treat.

If approved, the new therapy could be lucrative for AbbVie. It includes three experimental drugs and an approved treatment, an older drug called ritonavir. All of those drugs are delivered orally and they could have fewer side effects than older treatments. The regimen does not include interferon, an injection that has long been used as a standard treatment for hepatitis C. It causes nausea, diarrhea and other unpleasant side effects, and several companies are trying to develop hepatitis C treatments that don't include it.

Shares of AbbVie Inc. rose $1.20, or 2.5 percent, to $49.51 in midday trading. Shares of Enanta Pharmaceuticals Inc., which helped develop one of the experimental drugs, also rose $3.41, or 11 percent, to $35.68.

AbbVie's biggest seller is Humira, which is prescribed to treat conditions including rheumatoid arthritis, psoriasis and Crohn's Disease. In the fourth quarter, sales rose 13 percent to $3.04 billion.

Overall, AbbVie's revenue fell 2 percent to $5.11 billion in the fourth quarter, while its net income fell to $1.13 billion, or 70 cents per share, from $1.54 billion, or 98 cents per share, in the last months of 2012.

Excluding one-time items, including costs related to its separation from Abbott Laboratories, earnings came to 82 cents per share.

Results matched the forecast of analysts polled by FactSet.

Excluding special charges, AbbVie said it earned $3.14 per share in 2013, and its revenue rose 2 percent to $18.79 billion.

The North Chicago, Ill.-based company expects to report adjusted net income of $3 to $3.10 per share in 2014. Analysts had forecast $3.13 per share.