Biomarkers for immune checkpoint inhibitors in solid tumors

Integrative Oncology Approaches to Supporting Immune Checkpoint Inhibitor Treatment of Solid Tumours

PURPOSE OF REVIEW

The goal of this review was to examine the role and practical applications of integrative oncology strategies in supporting immune checkpoint inhibitor (ICI) treatment of adult solid tumours.

RECENT FINDINGS

Beyond tumour-intrinsic factors, several patient-associated factors affect ICI response, including germline genetics, systemic inflammation, the gut microbiota, and diet. Current promising supportive interventions include a Mediterranean-style diet with over 20 g of fibre, regular exercise, use of live biotherapeutics, minimisation of PPI and antibiotic use, and ensuring vitamin D repletion, with many other integrative oncology approaches under study. Caution around medical cannabis use in patients on ICIs is advised due to previously documented adverse impact on overall survival, while VAE (Viscum album extract) therapy studies have not highlighted any safety concerns so far. With expanding ICI use, it is important to investigate and apply low-cost integrative oncology strategies to support better treatment outcomes and minimise adverse events. Further research may lead to pre-treatment assessment of both tumour and patient-associated biomarkers and personalised multimodal prehabilitation care plans, as well as on-treatment support with targeted nutrition, physical activity, and supplementation regimes, including both systemic inflammation and gut microbiome modulating strategies. Given the emerging understanding of chronic stress impact on ICI treatment outcomes, mind-body approaches require further investigation.

Programmed death ligand-1 (PD-L1) clone 22C3 expression in resected colorectal cancer as companion diagnostics for immune checkpoint inhibitor therapy: A comparison study and inter-rater agreement evaluation across proposed cut-offs and predictive (TPS, CPS and IC) scores

BACKGROUND

Expression of programmed death ligand-1 (PD-L1) guides the use of immune checkpoint inhibitors (ICI) in several cancers. In colorectal cancer (CRC), ICI are only approved for metastatic CRC, while several studies suggest high efficacy even in operable CRC. The aim of this study was to investigate the inter-rater agreement of PD-L1 as a companion diagnostic marker.

METHODS

Specimens from resected stage I-III CRC (n = 166 tumors) were stained with PD-L1 22C3 clone. PD-L1 expression was scored by two pathologists as tumor proportion score (TPS), combined positive score (CPS) and immune cell score (IC). Inter-rater agreement was tested using three different agreement coefficients.

RESULTS

Raw scores of the two pathologists had 'good' to 'excellent' correlation. Spearman's rho for TPS=0.917 (95 %CI 0.839-0.995), for CPS=0.776 (95 %CI 0.726-0.826) and IC=0.818 (95 %CI 0.761-0.875). For TPS, kappa (κ)-agreements for both the ≥1 % and ≥10 % cutoffs had excellent correlation. For CPS the ≥1 % and ≥10 % cutoffs demonstrated κ=0.32 (95 %CI 0.12-0.51) and κ=0.36 (95 %CI 0.25-0.48) respectively. Cutoffs for IC showed κ=0.53 (95 %CI 0.18-0.79) for the ≥1 % cutoff, and κ=0.61 (95 %CI 0.48-0.73) for the ≥10 % cutoff. Gwet's agreement coefficient (AC1) showed higher agreement coefficients than κ-values for most, but not all cut-offs.

CONCLUSION

Agreement for PD-L1 was good to excellent for raw scores. Agreement variation across several criteria and cut-offs suggests the need for more robust criteria for PD-L1 as a companion diagnostic marker.