Conclusion
These findings provide insights into how the baseline differentiation status of the peripheral immune system determines responses to PD-1-targeted therapies.
Methods
We carried out a prospective study on a total of 77 NSCLC patients receiving anti-PD-1 blockers, among which 47 patients were assigned as a discovery cohort and 30 patients as a validation cohort. Peripheral blood samples were obtained at baseline and upon multiple therapy cycles and analyzed by multi-parameter flow cytometry.
Results
We found that a higher baseline ratio of PD-1+ early effector memory CD8+ T cells (CD28+CD27-CD45RO+, TEEM) to PD-1+ effector CD8+ T cells (CD28-CD27-CD45RO-, TE) delineated responders to PD-1 blockade from progressors and was associated with prolonged progression-free survival (PFS) and durable clinical benefit. Moreover, PD-1+CD8 TEEM cells exhibited early responses after anti-PD-1 therapy and was the major fraction of cycling PD-1+Ki67+CD8+ T cells to expand specifically with positive impact on PFS.