Companion Diagnostics: Lessons Learned and the Path Forward From the Programmed Death Ligand-1 Rollout

Area of Science:

• Oncology
• Immunotherapy
• Pathology

Background:

• Programmed death ligand-1 (PD-L1) immunohistochemistry companion diagnostics are crucial predictive markers for immune checkpoint inhibitor therapy.
• A complex testing environment with diverse cancer types, numerous inhibitors, and multiple PD-L1 antibodies has caused confusion among pathologists and oncologists.

Purpose of the Study:

• To identify factors contributing to challenges in programmed death receptor-1 (PD-1)/PD-L1 companion diagnostics.
• To propose solutions based on input from industry stakeholders and the College of American Pathologists.

Main Methods:

• A modified root cause analysis was employed during a meeting with pharmaceutical, in vitro diagnostic companies, and the Personalized Health Care Committee.
• The analysis reviewed the PD-L1 companion diagnostic assay release process to pinpoint shortcomings.

Main Results:

• Recommended improvements include enhanced multi-stakeholder communication.
• Suggested enhancements involve increased regulatory flexibility for postapproval medical knowledge and better information exchange between medical oncology and pathology societies.
• Improved postmarket training programs were also recommended.

Conclusions:

• The evolving landscape of companion diagnostics necessitates a thorough review of their design, implementation, and oversight processes.
• Addressing these complexities is vital for the effective use of PD-L1 assays in cancer treatment.