How test developers are seeking harmony for tumor mutational burden assays
Having learned their lesson with PD-L1, companies are collaborating on assay standards for tumor mutation burden -- a likely contender for the next major biomarker in immuno-oncology. A Friends of Cancer Research-led consortium of pharmas and diagnostics companies is driving the charge and plans to publish a white paper with its recommendations this year.
The coalition has been gathering members and momentum since it began meeting in September to create a framework for comparing tests on tumor mutation burden (TMB).
So far, discussions have included representatives from Friends, FDA, six test developers and six pharmas -- AstraZeneca plc, Bristol-Myers Squibb Co., the Genentech Inc. unit of Roche, the EMD Serono Inc. subsidiary of Merck KGaA, Merck & Co. Inc. and Pfizer Inc.
The partners are aiming to avoid the problems created for drug developers by the lack of harmony over assays for PD-L1. Four immunohistochemistry (IHC) assays, each with its own scoring algorithm and method of measuring cells, were used to support trials for at least five Phase III mAbs against PD-1 or PD-L1. That has made it nearly impossible to compare results across the class and determine what level of PD-L1 expression predicts patient benefit.
In 2015, a group of 10 companies, regulatory agencies and cancer associations launched the Blueprint Project to compare PD-L1 assays, standardize scoring and recommend best practices. The project published the first phase of its analysis last year in the Journal of Thoracic Oncology.
Since TMB could upstage PD-1/PD-L1 for stratifying patients in cancer immunology, stakeholders are pooling heads now