Functional binding of PD1 ligands predicts response to anti-PD1 treatment in patients with cancer

Accurate predictive biomarkers of response to immune checkpoint inhibitors (ICIs) are required for better stratifying patients with cancer to ICI treatments. Here, we present a new concept for a bioassay to predict the response to anti-PD1 therapies, which is based on measuring the binding functionality of PDL1 and PDL2 to their receptor, PD1. In detail, we developed a cell-based reporting system, called the immuno-checkpoint artificial reporter with overexpression of PD1 (IcAR-PD1) and evaluated the functionality of PDL1 and PDL2 binding in tumor cell lines, patient-derived xenografts, and fixed-tissue tumor samples obtained from patients with cancer. In a retrospective clinical study, we found that the functionality of PDL1 and PDL2 predicts response to anti-PD1 and that the functionality of PDL1 binding is a more effective predictor than PDL1 protein expression alone. Our findings suggest that assessing the functionality of ligand binding is superior to staining of protein expression for predicting response to ICIs.

A study of inflammation-based predictors of tumor response to neoadjuvant chemoradiotherapy for locally advanced rectal cancer

BACKGROUND

The ability of pretreatment laboratory markers of acute-phase inflammatory reactions like serum albumin level (SAL), hemoglobin (Hb), and absolute blood cell counts to predict complete pathological response (CPR) to neoadjuvant chemoradiotherapy (NACRT) in patients with locally advanced rectal cancer (LARC) has not yet been fully studied.

METHODS

We retrospectively examined the relation between SAL, Hb and absolute blood cell counts, and CPR rates in 140 LARC patients treated with NACRT.

RESULTS

Univariate analysis showed a significantly higher probability of CPR to NACRT in patients with clinical stage (CS) III LARC who had SAL >3.5 mg/dl (OR = 2.39; p = 0.04) and a neutrophil-to-lymphocyte ratio (NLR) value <5 (OR = 2.86; p = 0.03). The relation of CPR with SAL (OR = 2.11; p = 0.048) and NLR (OR = 2.54; p = 0.04) was confirmed by multivariate analysis in the same subset of patients. None of the parameters studied predicted CPR in patients with CS II disease. Patients who achieved CPR to NACRT had a higher probability of 5-year overall survival (HR 0.48; p = 0.01) and 5-year disease-free survival (HR 0.33; p = 0.003).

CONCLUSIONS

Our data indicate that SAL >3.5 mg/dl and NLR <5 may be positively related to CPR after NACRT in patients with CS III LARC. Hypoalbuminemia and a high NLR may be considered an indication for a more aggressive approach to NACRT and postoperative adjuvant chemotherapy in this subset of patients. This hypothesis requires confirmation in a randomized study.