The U.S. Food and Drug Administration said on Monday it had approved a drug to be sold by Bristol-Myers Squibb Co as a treatment for a form of blood cancer.

The FDA said it approved the treatment, Empliciti, to be used in multiple myeloma patients in combination with Celgene Corp's Revlimid and common anti-inflammatory drug dexamethasone.

The National Cancer Institute estimates there will be 26,850 new cases of multiple myeloma and 11,240 related deaths in the United States in 2015.

Research has shown that combination treatments increase the time that multiple myeloma patients survive without the disease.

The FDA said that Empliciti is the second immuno-oncology treatment for multiple myeloma to be approved, after Johnson & Johnson's Darzalex.

Bristol-Myers and AbbVie Inc co-developed the drug, but Empliciti will be sold only by Bristol-Myers.

The company is considered the leader among drugmakers racing to develop a new wave of cancer treatments that harness the immune system, including its recently approved immuno-oncology product Opdivo.

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Opdivo was approved in December for advanced melanoma and was approved in March to treat the less-common squamous type of non-small cell lung cancer.

Sales of Opdivo reached $305 million the latest quarter, putting it on track to become a blockbuster product.

Bristol-Myers shares were down about 1 percent at $67.22 on Monday morning on the New York Stock Exchange.