(Reuters) -The U.S. Food and Drug Administration has approved AbbVie Inc and Danish drugmaker Genmab's blood cancer therapy for adult patients who have received at least two prior lines of treatment, the companies said on Friday.

The drug, epcoritamab, to be sold under the brand name Epkinly was developed to treat a type of advanced large B-cell lymphoma, a cancer that starts in white blood cells.

Epcoritamab belongs to a class of drugs called bispecific antibodies that uses complex therapeutic proteins with the potential to latch onto the body's immune cells and attack cancer cells.

The approval makes epcoritamab the first of its kind to get the FDA's nod for the disease which has about 150,000 new cases each year globally.

Swiss drugmaker Roche's glofitamab is under review by the FDA for use in the same set of patients.

The approval expands Abbvie's product pipeline as it looks to cushion the blow to sales from fresh competition for its flagship arthritis drug Humira.

Jefferies analyst Peter Welford estimated the drug to reach $2.75 billion in peak sales globally.

"The race to market is tight, but epcoritamab's best-in-class efficacy and convenient subcutaneous (under the skin) administration are key advantages," TD Cowen analyst Yaron Werber said in a note ahead of the approval.

The approval is based on data from a mid-stage study which showed epcoritamab injection under the skin helped 63% patients whose cancer decreased in size or disappeared after treatment.

The drug is being co-developed by AbbVie and Genmab as part of a $750 million deal which the companies made in 2020 to jointly develop and commercialize three of Genmab's cancer-targeting antibody products.

Under the deal, the companies will share commercial responsibilities in the U.S. and Japan, with AbbVie responsible for further global commercialization.

(Reporting by Mariam Sunny in Bengaluru; Editing by Shailesh Kuber)