Aranzazu Fernandez-Martinez, Tomás Pascual, Baljit Singh, Paolo Nuciforo, Naim U. Rashid, Karla V. Ballman, Jordan D. Campbell, Katherine A. Hoadley, Patricia A. Spears, Laia Pare, Fara Brasó-Maristany, Nuria Chic, Ian Krop, Ann Partridge, Javier Cortés, Antonio Llombart-Cussac, Aleix Prat, Charles M. Perou, Lisa A. Carey, Institut Català de la Salut, [Fernandez-Martinez A] Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill. Department of Genetics, University of North Carolina, Chapel Hill. [Pascual T] Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill. Department of Medical Oncology, Hospital Clínic de Barcelona, Barcelona, Spain. Translational Genomics and Targeted Therapeutics in Solid Tumors, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain. SOLTI Breast Cancer Cooperative Group, Barcelona, Spain. [Singh B] Department of Pathology, White Plains Hospital, White Plains, New York. [Nuciforo P] Molecular Oncology Laboratory, Vall d’Hebron Institute of Oncology (VHIO), Barcelona, Spain. [Rashid NU] Department of Biostatistics, University of North Carolina, Chapel Hill. [Ballman KV] Alliance Statistics and Data Management Center, Mayo Clinic, Rochester, Minnesota, and Vall d'Hebron Barcelona Hospital Campus
ImportanceBoth tumor-infiltrating lymphocytes (TILs) assessment and immune-related gene expression signatures by RNA profiling predict higher pathologic complete response (pCR) and improved event-free survival (EFS) in patients with early-stage ERBB2/HER2-positive breast cancer. However, whether these 2 measures of immune activation provide similar or additive prognostic value is not known.ObjectiveTo examine the prognostic ability of TILs and immune-related gene expression signatures, alone and in combination, to predict pCR and EFS in patients with early-stage ERBB2/HER2-positive breast cancer treated in 2 clinical trials.Design, Setting, and ParticipantsIn this prognostic study, a correlative analysis was performed on the Cancer and Leukemia Group B (CALGB) 40601 trial and the PAMELA trial. In the CALGB 40601 trial, 305 patients were randomly assigned to weekly paclitaxel with trastuzumab, lapatinib, or both for 16 weeks. The primary end point was pCR, with a secondary end point of EFS. In the PAMELA trial, 151 patients received neoadjuvant treatment with trastuzumab and lapatinib for 18 weeks. The primary end point was the ability of the HER2-enriched subtype to predict pCR. The studies were conducted from October 2013 to November 2015 (PAMELA) and from December 2008 to February 2012 (CALGB 40601). Data analyses were performed from June 1, 2020, to January 1, 2022.Main Outcomes and MeasuresImmune-related gene expression profiling by RNA sequencing and TILs were assessed on 230 CALGB 40601 trial pretreatment tumors and 138 PAMELA trial pretreatment tumors. The association of these biomarkers with pCR (CALGB 40601 and PAMELA) and EFS (CALGB 40601) was studied by logistic regression and Cox analyses.ResultsThe median age of the patients was 50 years (IQR, 42-50 years), and 305 (100%) were women. Of 202 immune signatures tested, 166 (82.2%) were significantly correlated with TILs. In both trials combined, TILs were significantly associated with pCR (odds ratio, 1.01; 95% CI, 1.01-1.02; P = .02). In addition to TILs, 36 immune signatures were significantly associated with higher pCR rates. Seven of these signatures outperformed TILs for predicting pCR, 6 of which were B-cell related. In a multivariable Cox model adjusted for clinicopathologic factors, including PAM50 intrinsic tumor subtype, the immunoglobulin G signature, but not TILs, was independently associated with EFS (immunoglobulin G signature–adjusted hazard ratio, 0.63; 95% CI, 0.42-0.93; P = .02; TIL-adjusted hazard ratio, 1.00; 95% CI, 0.98-1.02; P = .99).Conclusions and RelevanceResults of this study suggest that multiple B-cell–related signatures were more strongly associated with pCR and EFS than TILs, which largely represent T cells. When both TILs and gene expression are available, the prognostic value of immune-related signatures appears to be superior.