(Reuters) - U.S. drugmaker AbbVie Inc's (>> AbbVie Inc) revenue beat analysts' estimates for the fourth straight quarter as sales of arthritis drug Humira jumped nearly 11 percent.

The company, however, reported a net loss of $810 million (537.47 million pounds), or 51 cents per share, for the fourth quarter, mainly due to a charge related to its aborted $55 billion deal to buy British drugmaker Shire Plc (>> Shire PLC).

Excluding the charge and other special items, AbbVie earned 89 cents per share. Analysts on average had expected 86 cents per share, according to Thomson Reuters I/B/E/S.

Revenue rose 6.7 percent to $5.45 billion, above the average analyst estimate of $5.36 billion.

Sales of Humira, which AbbVie inherited from Abbott Laboratories (>> Abbott Laboratories) in 2013, rose to $3.36 billion in the fourth quarter ended Dec. 31.

AbbVie kept its 2015 forecast from Jan. 8 unchanged.

The company expects 2015 earnings of $4.25-$4.45 per share, up sharply from last year's $3.32 per share, citing demand for its all-oral Viekira Pak hepatitis C treatment and growing sales of Humira.

Analysts expect Viekira Pak, approved by U.S. regulators in December, to eventually command about 25 percent of the lucrative hepatitis C market.

The drug competes with Gilead Sciences Inc's (>> Gilead Sciences, Inc.) Harvoni, a combination pill that has a list price of $93,400 for 12 weeks of treatment.

Pharmacy benefit manager Express Scripts (>> Express Scripts Holding Co) has backed AbbVie's therapy, saying it got a significant price discount compared with Harvoni and Sovaldi, a predecessor treatment from Gilead that is one of the two components of Harvoni.

Insurers UnitedHealth Group Inc (>> UnitedHealth Group Inc.), Aetna Inc (>> Aetna Inc), Humana Inc (>> Humana Inc) and Anthem Inc (>> Anthem Inc) have all backed Gilead, as has pharmacy benefit manager CVS Health (>> CVS Health Corp).

(Reporting by Ransdell Pierson; and Vidya L Nathan in Bengaluru; Editing by Don Sebastian and Saumyadeb Chakrabarty)