A new blood cancer drug from Bristol-Myers Squibb and AbbVie is speeding toward FDA approval, winning a priority review to treat multiple myeloma.

The antibody, called elotuzumab, is designed to focus the immune system’s attention on a protein called SLAMF7, which is expressed by tumor cells that might otherwise go unnoticed by the body’s natural defenses. With the priority review tag, the FDA pledges to give the two companies a final decision within six months, shortening the standard 10-month time frame.

Bristol-Myers and AbbVie plan to market elotuzumab as Empliciti, with a goal of using the drug as part of a cocktail for multiple myeloma patients who already have undergone one or more rounds of therapy. In Phase III results submitted to the FDA, a combination of elotuzumab, Celgene’s Revlimid and generic dexamethasone beat out the two older drugs on their own. The antibody garnered the FDA’s all-important breakthrough-therapy designation in 2014 based on positive Phase II data, guaranteeing its makers access to top-level agency officials throughout the development process.

Elotuzumab has taken a long path to FDA review. In 2008, Bristol-Myers licensed the drug from PDL BioPharma for $30 million up front, shortly before PDL spun off its biotech division into a firm called Facet Biotech. Abbott Laboratories purchased Facet for $450 million five years ago and then spun off its proprietary pharma business into AbbVie in 2013, effectively partnering the new firm with Bristol-Myers at the same time. The two have now joined forces to strengthen their respective oncology portfolios.

Success with elotuzumab would follow New York-based Bristol-Myers’ well-documented work with Opdivo, an antibody that mobilizes an immune system attack on cancer by blocking the protein PD-1 and leads a new pack of oncology treatments that is positioned to bring in $30 billion or more at its peak.

Meanwhile, Illinois-based AbbVie is hoping to build out a franchise in blood cancer after spending $21 billion on Pharmacyclics and a 50% share of Imbruvica, its chronic lymphocytic leukemia (CLL) treatment. Alongside partner Roche, AbbVie is moving forward with the Phase III CLL treatment venetoclax, hoping it can piece together a winning combination.