Performance Analysis of Leica Biosystems Monoclonal Antibody Programmed Cell Death Ligand 1 Clone 73-10 on Breast,...

Area of Science:

• Immunology
• Oncology
• Pathology

Background:

• The Programmed cell death receptor 1/Programmed cell death ligand 1 (PD-L1) pathway regulates immune responses.
• Anti-PD-L1 immunotherapy is crucial for managing various cancers and improving patient outcomes.
• Accurate detection of PD-L1 expression is essential for guiding immunotherapy decisions.

Purpose of the Study:

• To evaluate the performance of the Leica Biosystems (LBS) USA FDA class I in vitro diagnostic monoclonal antibody (clone 73-10) for PD-L1 detection.
• To compare the LBS 73-10 clone against established class III FDA-approved PD-L1 antibodies (SP263, 22C3, 28-8).
• To assess PD-L1 expression in breast, colorectal, and hepatocellular carcinomas.

Main Methods:

• Utilized 208 unique tissue microarray cases for each cancer type (breast, colorectal, hepatocellular carcinoma).
• Compared LBS 73-10 clone with Ventana SP263, Dako 22C3, and Dako 28-8 antibodies.
• Analyzed interassay concordance and inter-pathologist agreement using Cohen kappa coefficient (K) at 1% and 50% tumor proportion score (TPS) and 1% immune cell proportion score (IPS) cutoffs.

Main Results:

• Interassay concordances for LBS 73-10 ranged from 0.59 to 0.95 (K) for TPS cutoffs (1% and 50%).
• Inter-pathologist agreements for LBS 73-10 ranged from 0.53 to 1.0 (K) for TPS cutoffs.
• The LBS 73-10 assay demonstrated high sensitivity (78.3%-100%) and specificity (97.9%-100%) across different tumor types and cutoffs.

Conclusions:

• The LBS 73-10 monoclonal antibody exhibits technical performance comparable to FDA-approved PD-L1 detection assays.
• This antibody is a viable option for detecting PD-L1 expression in breast, colorectal, and hepatocellular carcinomas.
• The findings support the potential utility of the LBS 73-10 assay in companion/complementary diagnostics for PD-L1 targeted immunotherapies.