Comparison of SP142 and 22C3 Immunohistochemistry PD-L1 Assays for Clinical Efficacy of Atezolizumab in Non–Small Cell Lung Cancer: Results From the Randomized OAK Trial

Shirish Gadgeel, Fred R. Hirsch, Keith Kerr, Fabrice Barlesi, Keunchil Park, Achim Rittmeyer, Wei Zou, Namrata Bhatia, Hartmut Koeppen, Sarah M. Paul, David Shames, Jing Yi, Christina Matheny, Marcus Ballinger, Mark McCleland, David R. Gandara

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Background: This phase III OAK trial (NCT02008227) subgroup analysis (data cutoff, January 9, 2019) evaluated the predictive value of 2 PD-L1 IHC tests (VENTANA SP142 and Dako 22C3) for benefit from atezolizumab versus docetaxel by programmed death ligand 1 (PD-L1) status in patients with previously treated metastatic non–small cell lung cancer. Methods: PD-L1 expression was assessed prospectively with SP142 on tumor cells (TC) and tumor-infiltrating immune cells (IC) and retrospectively with 22C3 using a tumor proportion score (TPS) based on TC membrane staining. Efficacy was assessed in the 22C3 biomarker-evaluable population (22C3-BEP) (n = 577; 47.1% of SP142-intention-to-treat population) and non–22C3-BEP (n = 648) in PD-L1 subgroups (high, low, and negative) and according to selection by 1 or both assays. Results: In the 22C3-BEP, overall survival benefits with atezolizumab versus docetaxel were observed across PD-L1 subgroups; benefits were greatest in SP142-defined PD-L1–high (TC3 or IC3: hazard ratio [HR], 0.39 [95% confidence interval (CI), 0.25-0.63]) and 22C3-defined PD-L1–high (TPS ≥ 50%: HR, 0.56 [95% CI, 0.38-0.82]) and low (TPS, 1% to < 50%: HR, 0.55 [95% CI, 0.37-0.82]) groups. Progression-free survival improved with increasing PD-L1 expression for both assays. SP142 and 22C3 assays identified overlapping and unique patient populations in PD-L1–high, positive, and negative subgroups. Overall survival and progression-free survival benefits favored atezolizumab over docetaxel in double PD-L1–positive and negative groups; patients with both SP142- and 22C3-positive tumors derived the greatest benefit. Conclusions: Despite different scoring algorithms and differing sensitivity levels, the SP142 and 22C3 assays similarly predicted atezolizumab benefit at validated PD-L1 thresholds in patients with non–small cell lung cancer.

Original languageEnglish (US)
Pages (from-to)21-33
Number of pages13
JournalClinical Lung Cancer
Volume23
Issue number1
DOIs
StatePublished - Jan 2022
Externally publishedYes

Keywords

  • Biomarker-evaluable population
  • Inter-assay concordance
  • Overall survival
  • Programmed death ligand 1
  • Progression-free survival

ASJC Scopus subject areas

  • Oncology
  • Pulmonary and Respiratory Medicine
  • Cancer Research

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