High PD-1/PD-L1 Checkpoint Interaction Infers Tumor Selection and Therapeutic Sensitivity to Anti-PD-1/PD-L1 Treatment

Abstract

Many cancers are termed immunoevasive due to expression of immunomodulatory ligands. Programmed death ligand-1 (PD-L1) and cluster of differentiation 80/86 (CD80/86) interact with their receptors, programmed death receptor-1 (PD-1) and cytotoxic Tlymphocyte associated protein-4 (CTLA-4) respectively, on tumorinfiltrating leukocytes eliciting immunosuppression. Immunotherapies aimed at blocking these interactions are revolutionizing cancer treatments, albeit in an inadequately described patient subset. To address the issue of patient stratification for immune checkpoint intervention, we quantitatively imaged PD-1/PD-L1 interactions in tumor samples from patients, employing an assay that readily detects these intercellular proteinprotein interactions in the less than or equal to 10nm range. These analyses across multiple patient cohorts demonstrated the intercancer, inter-patient, and intra-tumoral heterogeneity of interacting immune checkpoints. The PD-1/PD-L1 interaction was not correlated with clinical PD-L1 expression scores in malignant melanoma. Crucially, amongst anti-PD-1 treated metastatic NSCLC patients, those with lower PD-1/PD-L1 interaction had significantly worsened survival. It is surmised that within tumors selecting for an elevated level of PD-1/PD-L1 interaction, there is a greater dependence on this pathway for immune evasion and hence they exhibit more impressive patient response to intervention. Research.

Predicting Response to Immunotherapy in Metastatic Renal Cell Carcinoma

“…Therefore, immunotherapy should not be withheld for patients who are known to be PD-L1−. New imaging modalities are being developed to quantify PD-1 and PD-L1, which may help reduce some of the variability in future studies [ 78 , 79 ]. TMB, while recently approved as a tumor-agnostic biomarker for response to pembrolizumab, has been shown to be an unreliable predictor in RCC and should not be used in clinical decision making for these patients.…”

Immunogenomic profile of colorectal cancer response to immune checkpoint blockade

“…Consistent with their low expression, we could detect PD1-PDL1 protein complex formation via A-FRET in only 12 of the 58 analysed regions (Supplementary Table 2). Moreover, the values of A-FRET intensity were lower than in melanoma and renal cancer 16 . The proportion of regions with detectable PD1-PDL1 complex was significantly less in hypermutated than in non-hypermutated CRCs, while there was no difference between DB-and nDB-CRCs (Fig.4M).…”

“…A total of 58 regions in slides K1-2 of the discovery cohort (Supplementary Table 2) were submitted to FASTBASE Solutions (Derio, Spain) to measure the interaction between PD1 and PDL1 in situ via amplified immune Förster Resonance Energy Transfer (i-FRET) 16 . Slides K1 were incubated overnight at 4 ºC with anti PD1 primary antibody (Supplementary Table 5) for donor only analyses.…”

Quantification of biomarker functionality predicts patient outcomes

“…1a). 5 This assay is termed iFRET. Alternative assays exist which attempt to measure PD-1/PD-L1 interaction, however unlike iFRET these report on distances that likely reflect juxtaposition and cannot be relied upon to accurately report on checkpoint receptor engagement.…”

“…Crucially, the iFRET assay was able to detect a PD-1/PD-L1 interaction in 10 of the 11 PD-L1 negative ccRCC patients. 5 This demonstrates that ligand expression is a poor surrogate of receptor engagement and that the direct functional PD-1/PD-L1 interaction needs to be quantified. Following this analysis, iFRET was used to assess PD-1/PD-L1 interaction states in 176 malignant melanoma patients with known clinical outcomes.…”