Digital Quantification of Tumor PD-L1 Predicts Outcome of PD-1-Based Immune Checkpoint Therapy in Metastatic Melanoma

Jan Malte Placke*, Camille Soun, Jenny Bottek, Rudolf Herbst, Patrick Terheyden, Jochen Utikal, Claudia Pföhler, Jens Ulrich, Alexander Kreuter, Christiane Pfeiffer, Peter Mohr, Ralf Gutzmer, Friedegund Meier, Edgar Dippel, Michael Weichenthal, Lisa Zimmer, Elisabeth Livingstone, Jürgen C. Becker, Georg Lodde, Antje SuckerKlaus Griewank, Susanne Horn, Eva Hadaschik, Alexander Roesch, Dirk Schadendorf, Daniel Robert Engel, Selma Ugurel

*Corresponding author for this work
9 Citations (Scopus)

Abstract

Background: PD-1-based immune checkpoint blockade (ICB) is a highly effective therapy in metastatic melanoma. However, 40-60% of patients are primarily resistant, with valid predictive biomarkers currently missing. This study investigated the digitally quantified tumor PD-L1 expression for ICB therapy outcome prediction. Patients and Methods: Tumor tissues taken prior to PD-1-based ICB for unresectable metastatic disease were collected within the prospective multicenter Tissue Registry in Melanoma (TRIM). PD-L1 expression (clone 28-8; cut-off=5%) was determined by digital and physician quantification, and correlated with therapy outcome (best overall response, BOR; progression-free survival, PFS; overall survival, OS). Results: Tissue samples from 156 patients were analyzed (anti-PD-1, n=115; anti-CTLA-4+anti-PD-1, n=41). Patients with PD-L1-positive tumors showed an improved response compared to patients with PD-L1-negative tumors, by digital (BOR 50.5% versus 32.2%; p=0.026) and physician (BOR 54.2% versus 36.6%; p=0.032) quantification. Tumor PD-L1 positivity was associated with a prolonged PFS and OS by either digital (PFS, 9.9 versus 4.6 months, p=0.021; OS, not reached versus 13.0 months, p=0.001) or physician (PFS, 10.6 versus 5.6 months, p=0.051; OS, not reached versus 15.6 months, p=0.011) quantification. Multivariable Cox regression revealed digital (PFS, HR=0.57, p=0.007; OS, HR=0.44, p=0.001) and physician (OS, HR=0.54, p=0.016) PD-L1 quantification as independent predictors of survival upon PD-1-based ICB. The combination of both methods identified a patient subgroup with particularly favorable therapy outcome (PFS, HR=0.53, p=0.011; OS, HR=0.47, p=0.008). Conclusion: Pre-treatment tumor PD-L1 positivity predicted a favorable outcome of PD-1-based ICB in melanoma. Herein, digital quantification was not inferior to physician quantification, and should be further validated for clinical use.

Original languageEnglish
Article number741993
JournalFrontiers in Oncology
Volume11
ISSN2234-943X
DOIs
Publication statusPublished - 21.09.2021

Research Areas and Centers

  • Academic Focus: Center for Infection and Inflammation Research (ZIEL)
  • Research Area: Luebeck Integrated Oncology Network (LION)
  • Centers: University Cancer Center Schleswig-Holstein (UCCSH)

DFG Research Classification Scheme

  • 205-19 Dermatology
  • 204-05 Immunology
  • 205-14 Haematology, Oncology

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