Relatlimab, which blocks a protein called LAG-3, is not yet approved, but the FDA has granted it priority review. 

Combining relatlimab and nivolumab (Opdivo) may double progression-free survival in patients with advanced melanoma, according to a new study in the New England Journal of Medicine.

Relatlimab, which blocks a protein called LAG-3, is not yet approved, but the U.S. Food and Drug Administration has granted it priority review. 

Researchers evaluated relatlimab and nivolumab as a fixed-dose combination compared with nivolumab alone when administered intravenously every four weeks to patients with previously untreated metastatic or unresectable melanoma.  

The median progression-free survival was 10.1 months with relatlimab–nivolumab as compared with 4.6 months with nivolumab, the study found. 

After one year, Progression-free survival at 12 months was 47.7 percent with relatlimab–nivolumab as compared with 36.0 percent with nivolumab. 

In the current trial, only 19 percent of patients on Opdivo/relatlimab reported serious side effects including liver inflammation, severe fatigue and diarrhea.

The new study was funded by Bristol Myers Squibb, the maker of both drugs.