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PD-1 Expression on Intratumoral Regulatory T Cells is Associated with Lack of Benefit from Anti-PD-1 Therapy in Metastatic Clear Cell Renal Cell Carcinoma Patients

Citation:

Denize T, Jegede OA, Matar S, El Ahmar N, West DJ, Walton E, Bagheri AS, Savla V, Nabil Laimon Y, Gupta S, et al. PD-1 Expression on Intratumoral Regulatory T Cells is Associated with Lack of Benefit from Anti-PD-1 Therapy in Metastatic Clear Cell Renal Cell Carcinoma Patients. Clin Cancer Res. 2023.

Date Published:

2023 Dec 07

Abstract:

PURPOSE: PD-1 expression on CD8+TIM-3-LAG3- tumor-infiltrating cells predicts positive response to PD-1 blockade in metastatic clear cell renal cell carcinoma (mccRCC). Since PD-1 signaling inhibition in regulatory T cells (Tregs) augments their immunosuppressive function, we hypothesized that PD-1 expression on tumor-infiltrating Tregs would predict resistance to PD-1 inhibitors. EXPERIMENTAL DESIGN: PD-1+ Tregs were phenotyped using multiparametric immunofluorescence in ccRCC tissues from the CheckMate-025 trial (nivolumab: n=91, everolimus: n=90). Expression of CD8, PD-1, TIM-3, and LAG-3 was previously determined (Ficial et al, 2021). Clinical endpoints included progression-free survival (PFS), overall survival (OS), and objective response rate (ORR). RESULTS: In the nivolumab (but not everolimus) arm, high percentage of PD-1+ Tregs was associated with shorter PFS (3.19 versus 5.78 months; p=0.021), shorter OS (18.1 versus 27.7 months, p=0.013) and marginally lower ORR (12.5% versus 31.3%, p=0.059). An integrated biomarker (PD-1 Treg/CD8 ratio) was developed by calculating the ratio between percentage of PD-1+Tregs (marker of resistance) and percentage of CD8+PD-1+TIM-3-LAG-3- cells (marker of response). In the nivolumab (but not everolimus) arm, patients with high-PD-1 ratio experienced shorter PFS (3.48 versus 9.23 months, p<0.001), shorter OS (18.14 versus 38.21 months, p<0.001) and lower ORR (15.69% versus 40.00%; p=0.009). Compared to the individual biomarkers, the PD-1 ratio showed improved ability to predict outcomes to nivolumab versus everolimus. CONCLUSIONS: PD-1 expression on Tregs is associated with resistance to PD-1 blockade in mccRCC, suggesting that targeting Tregs may synergize with PD-1 inhibition. A model that integrates PD-1 expression on Tregs and CD8+TIM-3-LAG3- cells has higher predictive value.