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Concordance of three different PD-L1 diagnostic tests - update


Concordance of three different PD-L1 diagnostic tests - update
Posted on December 07, 2016 by J Seabrook

Concordance of three different PD-L1 diagnostic assays (1)

MPLN’s PD-L1 assay, the Ventana SP263, was included in the concordance study of three PD-L1 Diagnostic Tests by AstraZeneca and results reported at AACR Annual Meeting 2016.

The study conducted by AstraZeneca (2), which complements a Blueprint initiative (3) addressing harmonization of the available PD-L1 assays, compares Ventana SP263 developed for use with AstraZeneca’s immunotherapeutic drug durvalumab, an anti-PD-L1; Dako pharmDx PD-L1 22C, a Companion Diagnostic for Merck’s Keytruda, and Dako pharmDx PD-L1 28-8 a complementary test with Opdivo. All three tests measure the percentage of positive staining for PD-L1 tumor cells with a unique cut-off point for positivity corresponding to potential therapeutic response in lung cancer patients. The three tests had an overall agreement of more than 90% based on testing 500 specimens with squamous and non-squamous histology. In addition, the recently published “Blueprint PD-L1 IHC Assay Comparison Project” demonstrated that SP263, 22C3, and 28-8 clones show close alignment on tumor cell staining (6). The performance characteristics of PD-L1 antibody clones is area of active investigation, and includes a second phase of the Blueprint Project which will compare antibody clones on biopsy material.

The interpretive criteria for each antibody are different (4) and for most labs it is not feasible to maintain all four antibodies. Concordance in PD-L1 testing is an emerging area of interest. NCCN is collaborating with Bristol-Myers Squibb (5) on a study to understand how different assays measure PD-L1 protein expression, to measure the concordance of pathologist interpretation of various test results, and to evaluate the heterogeneity of PD-L1 protein expression within tumor samples. Further, the College of American Pathologists (CAP) will be releasing proficiency testing for PD-L1 testing in 2017 which will indicate further practical concordance between laboratories.

  1. Scholl L.M. et al. 2016. Programmed Death Ligand-1 Immunohistochemistry—A New Challenge for Pathologists. A Perspective From Members of the Pulmonary Pathology Society Arch Pathol Lab Med. 140: 341-344.
  2. Comparison of Three Different PD-L1 Diagnostic Tests Shows a High Degree of Concordance.  AACR News
  3. FDA, AACR, ASCO workshop on “Complexities in Personalized Medicine: Harmonizing Companion Diagnostics Across a Class of Targeted Therapies”. An industry workgroup volunteered to develop a blueprint proposal using NSCLC as the use case indication
  4. Effort to "Harmonize" PD-L1 Assays Launched in NSCLC – Table. PD-L1 assays used in NSCLC clinical trials. Anita T.Schaffer Aug 14 2015.
  5. NCCN Collaborates with Bristol-Myers Squibb to Study PD-L1 Expression and Test Interpretation in Lung Cancer: NCCN News
  6. Hirsch FR et al.   PD-L1 Immunohistochemistry Assays for Lung Cancer: Results from Phase 1 of the "Blueprint PD-L1 IHC Assay Comparison Project.  J Thorac Oncol. 2016 Nov 29.

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