While the CheckMate 214 data show that the Opdivo/Yervoy combination works regardless of PD-L1 expression, Bristol is continuing to look for new biomarkers to help identify which patients are most likely to respond, Namouni said. "PD-L1 is one part of the story – it's not the full story," the exec said, adding that the company continues to refine biomarker research in all cancers and expects a variety, including tumor mutation burden, will be useful.

Research has shown that expression of lymphocyte-activating gene 3 (LAG-3) is associated with better response to Opdivo. The company presented preclinical data at the SITC meeting showing the correlation between LAG-3 and inflammation. Robin Edwards and colleagues concluded in a poster presentation that LAG-3 may be a predictive biomarker for therapy with Bristol's anti-LAG-3 antibody relatlimab (BMS 986016).

Bristol is planning a Phase I/IIa dose escalation and cohort expansion study of relatlimab with and without Opdivo in 1,000 patients with solid tumors.

"The LAG-3 ligand (MCHII) was seen in both high and low inflammation tumors but did not correlate with PD-L1 expression, which we think highlights its potential to be a second pathway that complements current PD-1 agents," Barclays analyst Geoff Meacham wrote in a Nov. 7 note.

Bristol's Strong SITC: IDO, 1L Kidney Cancer And New Mechanism Data Bode Well

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