This study will evaluate the antitumor activity of anti-LAG3 monoclonal antibody relatlimab and the anti-PD1 monoclonal antibody nivolumab in combination in subjects with unresectable or metastatic melanoma who have not received prior treatment with immunotherapy. The trial is designed with a lead-in phase of 2 cycles (4 week) treatment of either nivolumab, relatlimab, or the combination of nivolumab/relatlimab, followed by a combination phase of nivolumab/relatlimab treatment in all subjects. This lead-in design with accompanying tumor biopsies and peripheral blood analyses will enable mechanistic analyses of the effect of LAG3 and PD1 blockade alone and in combination to enhance understanding of mechanisms of response and resistance. Duration of response, progression free survival, and safety will be assessed as secondary objectives.
