Roche PD-L1 assay not concordant with others

A study led by scientists at AstraZeneca plc (LSE:AZN; NYSE:AZN) suggests that while three separate companion diagnostics measuring PD-L1 expression may be interchangeable, a fourth test developed as a companion diagnostic for Roche (SIX:ROG; OTCQX:RHHBY) and its Genentech Inc. unit’s Tecentriq atezolizumab produces disparate reports of PD-L1 expression. Understanding the differences between the diagnostics will bring scientists closer to standardizing the technique and producing a single test for PD-L1 status across immunotherapy products.

Researchers at AZ and colleagues reported that AZ's SP263 assay scored PD-L1 expression in infiltrating immune cells consistently with the 22C3 assay used by Merck & Co. Inc. (NYSE:MRK) and the 28-8 assay used by Bristol Myers Squibb Co. (NYSE:BMY). Specifically, concordance between the SP263 assay and the 22C3 and 28-8 assays ranged from 86.8-97% for various cut-offs of PD-L1 expression...