Blockade of LAG-3 and PD-1 leads to co-expression of cytotoxic and exhaustion gene modules in CD8+ T cells to promote antitumor immunity

Relatlimab (rela; anti-LAG-3) plus nivolumab (nivo; anti-PD-1) is safe and effective for treatment of advanced melanoma. We designed a trial (NCT03743766) where advanced melanoma patients received rela, nivo, or rela+nivo to interrogate the immunologic mechanisms of rela+nivo. Analysis of biospecimens from this ongoing trial demonstrated that rela+nivo led to enhanced capacity for CD8+ T cell receptor signaling and altered CD8+ T cell differentiation, leading to heightened cytotoxicity despite the retention of an exhaustion profile. Co-expression of cytotoxic and exhaustion signatures was driven by PRDM1, BATF, ETV7, and TOX. Effector function was upregulated in clonally expanded CD8+ T cells that emerged after rela+nivo. A rela+nivo intratumoral CD8+ T cell signature was associated with a favorable prognosis. This intratumoral rela+nivo signature was validated in peripheral blood as an elevated frequency of CD38+TIM3+CD8+ T cells. Overall, we demonstrated that cytotoxicity can be enhanced despite the retention of exhaustion signatures, which will inform future therapeutic strategies. [Display omitted] •Rela+nivo enhances response to T cell receptor and IFN-γ signaling in CD8+ T cells•Cytotoxic and exhaustion gene modules are co-expressed following rela+nivo•PRDM1, BATF, ETV7, and TOX drive rela+nivo cytotoxicity and exhaustion profile•Cytotoxicity and exhaustion profile is associated with clinical benefit Analysis of biospecimens from a phase 2 study of advanced melanoma shows that combined blockade of LAG-3 and PD-1 modulates the differentiation of CD8+ T cells by enhancing responses to T cell receptor and IFN-γ signaling, leading to enhanced effector functions despite the retention of an exhaustion profile.