Comparison of SP263 and 22C3 immunohistochemistry PD-L1 assays for clinical efficacy of adjuvant atezolizumab in non-small cell lung cancer: results from the randomized phase III IMpower010 trial

• Published in: Journal for immunotherapy of cancer 2023-10, Vol.11 (10), p.e007047
• Main Authors: Zhou, Caicun, Srivastava, Minu K, Xu, Hao, Felip, Enriqueta, Wakelee, Heather, Altorki, Nasser, Reck, Martin, Liersch, Rüdiger, Kryzhanivska, Anna, Oizumi, Satoshi, Tanaka, Hiroshi, Hamm, John, McCune, Steven L, Bennett, Elizabeth, Gitlitz, Barbara, McNally, Virginia, Ballinger, Marcus, McCleland, Mark, Zou, Wei, Das Thakur, Meghna, Novello, Silvia
• Format: Article
• Language: English
• Subjects: Adjuvants, Immunologic; B7-H1 Antigen - metabolism; Cancer; Cancer therapies; Carcinoma, Non-Small-Cell Lung - pathology; Chemotherapy; Humans; immune checkpoint inhibitors; Immunohistochemistry; Immunotherapy; Immunotherapy Biomarkers; Ligands; Lung cancer; Lung Neoplasms - pathology; Metastasis; Monoclonal antibodies; Mutation; non-small cell lung cancer; Patients; programmed cell death 1 receptor; Small Cell Lung Carcinoma; Targeted cancer therapy; Treatment Outcome; tumor biomarkers; Tumors
• ISSN: 2051-1426; 2051-1426
• DOI: 10.1136/jitc-2023-007047

BackgroundTumor samples from the phase III IMpower010 study were used to compare two programmed death-ligand 1 (PD-L1) immunohistochemistry assays (VENTANA SP263 and Dako 22C3) for identification of PD-L1 patient subgroups (negative, positive, low, and high expression) and their predictive value for adjuvant atezolizumab compared with best supportive care (BSC) in resectable early-stage non-small cell lung cancer (NSCLC).MethodsPD-L1 expression was assessed by the SP263 assay, which measured the percentage of tumor cells with any membranous PD-L1 staining, and the 22C3 assay, which scored the percentage of viable tumor cells showing partial or complete membranous PD-L1 staining.ResultsWhen examining the concordance at the PD-L1-positive threshold (SP263: tumor cell (TC)≥1%; 22C3: tumor proportion score (TPS)≥1%), the results were concordant between assays for 83% of the samples. Similarly, at the PD-L1–high cut-off (SP263: TC≥50%; 22C3: TPS≥50%), the results were concordant between assays for 92% of samples. The disease-free survival benefit of atezolizumab over BSC was comparable between assays for PD-L1-positive (TC≥1% by SP263: HR, 0.58 (95% CI: 0.40 to 0.85) vs TPS≥1% by 22C3: HR, 0.65 (95% CI: 0.45 to 0.95)) and PD-L1-high (TC≥50% by SP263: HR, 0.27 (95% CI: 0.14 to 0.53) vs TPS≥50% by 22C3: HR, 0.31 (95% CI: 0.16 to 0.60)) subgroups.ConclusionsThe SP263 and 22C3 assays showed high concordance and a comparable clinical predictive value of atezolizumab at validated PD-L1 thresholds, suggesting that both assays can identify patients with early-stage NSCLC most likely to experience benefit from adjuvant atezolizumab.Trial registration numberNCT02486718.