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International Journal of Cancer Oct 2017Anti-HER2 therapies are beneficial for patients with HER2-positive breast or gastric cancer. T-DM1 is a HER2-targeting antibody-drug conjugate (ADC) comprising the...
Anti-HER2 therapies are beneficial for patients with HER2-positive breast or gastric cancer. T-DM1 is a HER2-targeting antibody-drug conjugate (ADC) comprising the antibody trastuzumab, a linker, and the tubulin inhibitor DM1. Although effective in treating advanced breast cancer, all patients eventually develop T-DM1 resistance. DS-8201a is a new ADC incorporating an anti-HER2 antibody, a newly developed, enzymatically cleavable peptide linker, and a novel, potent, exatecan-derivative topoisomerase I inhibitor (DXd). DS-8201a has a drug-to-antibody-ratio (DAR) of 8, which is higher than that of T-DM1 (3.5). Owing to these unique characteristics and unlike T-DM1, DS-8201a is effective against cancers with low-HER2 expression. In the present work, T-DM1-resistant cells (N87-TDMR), established using the HER2-positive gastric cancer line NCI-N87 and continuous T-DM1 exposure, were shown to be susceptible to DS-8201a. The ATP-binding cassette (ABC) transporters ABCC2 and ABCG2 were upregulated in N87-TDMR cells, but HER2 overexpression was retained. Furthermore, inhibition of ABCC2 and ABCG2 by MK571 restored T-DM1 sensitivity. Therefore, resistance to T-DM1 is caused by efflux of its payload DM1, due to aberrant expression of ABC transporters. In contrast to DM1, DXd payload of DS-8201a inhibited the growth of N87-TDMR cells in vitro. This suggests that either DXd may be a poor substrate of ABCC2 and ABCG2 in comparison to DM1, or the high DAR of DS-8201a relative to T-DM1 compensates for increased efflux. Notably, N87-TDMR xenograft tumor growth was prevented by DS-8201a. In conclusion, the efficacy of DS-8201a as a treatment for patients with T-DM1-resistant breast or gastric cancer merits investigation.
Topics: Ado-Trastuzumab Emtansine; Animals; Antibodies, Monoclonal, Humanized; Camptothecin; Cell Line, Tumor; Drug Resistance, Neoplasm; Female; Humans; Immunoconjugates; Maytansine; Mice; Mice, Inbred BALB C; Mice, Nude; Multidrug Resistance-Associated Protein 2; Random Allocation; Receptor, ErbB-2; Stomach Neoplasms; Topoisomerase I Inhibitors; Trastuzumab
PubMed: 28677116
DOI: 10.1002/ijc.30870 -
ESMO Open Oct 2021Non-small-cell lung cancer (NSCLC) harbouring HER2 alterations is now considered a distinct molecular subtype. The activation of HER2 in NSCLC occurs via three... (Review)
Review
Non-small-cell lung cancer (NSCLC) harbouring HER2 alterations is now considered a distinct molecular subtype. The activation of HER2 in NSCLC occurs via three mechanisms, i.e. gene mutation (1%-4% of cases), gene amplification (2%-5%) and protein overexpression (2%-30%), with different prognostic and predictive outcomes. So far, non-selective tyrosine kinase inhibitors (TKIs) have shown a minor benefit in HER2-mutant NSCLC patients with objective response rates (ORRs) ranging from 0% to 19%. Trastuzumab-based chemotherapy was not found to be superior to chemotherapy alone [median progression-free survival (PFS) 6.1 versus 7 months, respectively] and dual HER2 antibody blockade with trastuzumab and pertuzumab had limited efficacy (ORR 13%-21%). In contrast, novel more selective HER2 TKIs such as poziotinib and pyrotinib have shown a promising activity in HER2-mutant pre-treated NSCLC patients, with response rates up to 38% and 44%, respectively. The most encouraging data come from phase II studies that evaluated the antibody-drug conjugates (ADCs) ado-trastuzumab-emtansine and trastuzumab-deruxtecan in patients with HER2-mutant NSCLC, with response rates of 50% and 62%, respectively. These agents are bringing hope to the management of HER2-altered NSCLC. Moreover, a paradigm shift from monotherapies towards combinations of agents with distinct mechanisms of action, such as ADCs with irreversible TKIs or immune checkpoint inhibitors, is already taking place and will change the therapeutic landscape of HER2-driven NSCLC. This paper provides a practical, concise and updated review on the therapeutic strategies in NSCLC with HER2 molecular alterations.
Topics: Ado-Trastuzumab Emtansine; Carcinoma, Non-Small-Cell Lung; Humans; Lung Neoplasms; Mutation; Receptor, ErbB-2
PubMed: 34479034
DOI: 10.1016/j.esmoop.2021.100260 -
ESMO Open Aug 2023The current treatment of patients with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer (ABC) has been greatly impacted in the past decade... (Review)
Review
The current treatment of patients with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer (ABC) has been greatly impacted in the past decade by the introduction of antibody-drug conjugates (ADCs), which represent a relatively novel therapeutic class with the peculiar ability to deliver otherwise overtly toxic chemotherapeutics to tumor sites by exploiting the specificities of monoclonal antibodies. Indeed, drug engineering refinements in ADC design, such as through the introduction of cleavable linkers and hydrophobic payloads, resulted in improved patient outcomes in recent years. Two different ADCs, namely trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd), have already entered clinical practice for the treatment of HER2-positive ABC. In this scenario, T-DXd has shown to portend better survival outcomes compared to T-DM1, while leaving a large unsought area of unmet medical need upon T-DXd failure. Treatment decision and benefit of cancer drugs following T-DXd still represent an area of clinical controversy, where a preclinical investigation and clinical development should be prioritized. As the pace of innovation is currently accelerating, and with novel ADC formulations advancing in early-phase clinical trials, the whole BC field is changing at an unprecedented rate, with potential broadenings of therapeutic indications. In this review, we present the clinical landscape of HER2-positive advanced BC and discuss our vision on how to tackle T-DXd resistance, providing a perspective on the priority areas of the cancer research in this setting.
Topics: Humans; Female; Breast Neoplasms; Antibodies, Monoclonal, Humanized; Trastuzumab; Ado-Trastuzumab Emtansine; Immunoconjugates
PubMed: 37467660
DOI: 10.1016/j.esmoop.2023.101608 -
The Lancet. Oncology Jun 2017The antibody-drug conjugate trastuzumab emtansine is indicated for the treatment of patients with HER2-positive metastatic breast cancer previously treated with... (Comparative Study)
Comparative Study Randomized Controlled Trial
Trastuzumab emtansine versus capecitabine plus lapatinib in patients with previously treated HER2-positive advanced breast cancer (EMILIA): a descriptive analysis of final overall survival results from a randomised, open-label, phase 3 trial.
BACKGROUND
The antibody-drug conjugate trastuzumab emtansine is indicated for the treatment of patients with HER2-positive metastatic breast cancer previously treated with trastuzumab and a taxane. Approval of this drug was based on progression-free survival and interim overall survival data from the phase 3 EMILIA study. In this report, we present a descriptive analysis of the final overall survival data from that trial.
METHODS
EMILIA was a randomised, international, open-label, phase 3 study of men and women aged 18 years or older with HER2-positive unresectable, locally advanced or metastatic breast cancer previously treated with trastuzumab and a taxane. Enrolled patients were randomly assigned (1:1) via a hierarchical, dynamic randomisation scheme and an interactive voice response system to trastuzumab emtansine (3·6 mg/kg intravenously every 3 weeks) or control (capecitabine 1000 mg/m self-administered orally twice daily on days 1-14 on each 21-day cycle, plus lapatinib 1250 mg orally once daily on days 1-21). Randomisation was stratified by world region (USA vs western Europe vs or other), number of previous chemotherapy regimens for unresectable, locally advanced, or metastatic disease (0 or 1 vs >1), and disease involvement (visceral vs non-visceral). The coprimary efficacy endpoints were progression-free survival (per independent review committee assessment) and overall survival. Efficacy was analysed in the intention-to-treat population; safety was analysed in all patients who received at least one dose of study treatment, with patients analysed according to the treatment actually received. On May 30, 2012, the study protocol was amended to allow crossover from control to trastuzumab emtansine after the second interim overall survival analysis crossed the prespecified overall survival efficacy boundary. This study is registered with ClinicalTrials.gov, number NCT00829166.
FINDINGS
Between Feb 23, 2009, and Oct 13, 2011, 991 eligible patients were enrolled and randomly assigned to either trastuzumab emtansine (n=495) or capecitabine and lapatinib (control; n=496). In this final descriptive analysis, median overall survival was longer with trastuzumab emtansine than with control (29·9 months [95% CI 26·3-34·1] vs 25·9 months [95% CI 22·7-28·3]; hazard ratio 0·75 [95% CI 0·64-0·88]). 136 (27%) of 496 patients crossed over from control to trastuzumab emtansine after the second interim overall survival analysis (median follow-up duration 24·1 months [IQR 19·5-26·1]). Of those patients originally randomly assigned to trastuzumab emtansine, 254 (51%) of 495 received capecitabine and 241 [49%] of 495 received lapatinib (separately or in combination) after study drug discontinuation. In the safety population (488 patients treated with capecitabine plus lapatinib, 490 patients treated with trastuzumab emtansine), fewer grade 3 or worse adverse events occurred with trastuzumab emtansine (233 [48%] of 490) than with capecitabine plus lapatinib control treatment (291 [60%] of 488). In the control group, the most frequently reported grade 3 or worse adverse events were diarrhoea (103 [21%] of 488 patients) followed by palmar-plantar erythrodysaesthesia syndrome (87 [18%]), and vomiting (24 [5%]). The safety profile of trastuzumab emtansine was similar to that reported previously; the most frequently reported grade 3 or worse adverse events in the trastuzumab emtansine group were thrombocytopenia (70 [14%] of 490), increased aspartate aminotransferase levels (22 [5%]), and anaemia (19 [4%]). Nine patients died from adverse events; five of these deaths were judged to be related to treatment (two in the control group [coronary artery disease and multiorgan failure] and three in the trastuzumab emtansine group [metabolic encephalopathy, neutropenic sepsis, and acute myeloid leukaemia]).
INTERPRETATION
This descriptive analysis of final overall survival in the EMILIA trial shows that trastuzumab emtansine improved overall survival in patients with previously treated HER2-positive metastatic breast cancer even in the presence of crossover treatment. The safety profile was similar to that reported in previous analyses, reaffirming trastuzumab emtansine as an efficacious and tolerable treatment in this patient population.
FUNDING
F Hoffmann-La Roche/Genentech.
Topics: Ado-Trastuzumab Emtansine; Adult; Aged; Aged, 80 and over; Anemia; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Aspartate Aminotransferases; Breast Neoplasms; Breast Neoplasms, Male; Bridged-Ring Compounds; Capecitabine; Diarrhea; Disease-Free Survival; Female; Hand-Foot Syndrome; Humans; Lapatinib; Male; Maytansine; Middle Aged; Quinazolines; Receptor, ErbB-2; Response Evaluation Criteria in Solid Tumors; Retreatment; Survival Rate; Taxoids; Thrombocytopenia; Trastuzumab; Vomiting; Young Adult
PubMed: 28526536
DOI: 10.1016/S1470-2045(17)30312-1 -
Cancer Research Oct 2021No targeted treatments are currently approved for exon 20 insertion-mutant lung adenocarcinoma patients. Mobocertinib (TAK-788) is a potent irreversible tyrosine kinase...
No targeted treatments are currently approved for exon 20 insertion-mutant lung adenocarcinoma patients. Mobocertinib (TAK-788) is a potent irreversible tyrosine kinase inhibitor (TKI) designed to target human epidermal growth factor receptor 2 () exon 20 insertion mutations. However, the function of mobocertinib on exon 20 insertion-mutant lung cancer is still unclear. Here we conducted systematic characterization of preclinical models to understand the activity profile of mobocertinib against exon 20 insertions. In exon 20 insertion-mutant cell lines, the IC of mobocertinib was higher than poziotinib and comparable with or slightly lower than afatinib, neratinib, and pyrotinib. Mobocertinib had the lowest HER2 exon 20 insertion IC/wild-type (WT) EGFR IC ratio, indicating that mobocertinib displayed the best selectivity profile in these models. Also, mobocertinib showed strong inhibitory activity in exon 20 allograft and patient-derived xenograft models. In genetically engineered mouse models, exon 20 lung tumors exhibited a sustained complete response to mobocertinib, whereas exon 20 tumors showed only partial and transient response. Combined treatment with a second antibody-drug conjugate (ADC) against , ado-trastuzumab emtansine (T-DM1), synergized with mobocertinib in exon 20 tumors. In addition to the tumor cell autonomous effect, sustained tumor growth control derived from M1 macrophage infiltration and CD4 T-cell activation. These findings support the ongoing clinical development of mobocertinib (NCT02716116) and provide a rationale for future clinical evaluation of T-DM1 combinational therapy in exon 20 insertion-mutant lung adenocarcinoma patients. SIGNIFICANCE: This study elucidates the potent inhibitory activity of mobocertinib against exon 20 insertion-mutant lung cancer and the synergic effect of combined mobocertinib and T-DM1, providing a strong rationale for clinical investigation.
Topics: Adenocarcinoma of Lung; Ado-Trastuzumab Emtansine; Animals; Antibodies, Bispecific; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Proliferation; Exons; Female; Gene Expression Regulation, Neoplastic; Humans; INDEL Mutation; Lung Neoplasms; Mice; Mice, Inbred NOD; Mice, SCID; Receptor, ErbB-2; Tumor Cells, Cultured; Xenograft Model Antitumor Assays
PubMed: 34380634
DOI: 10.1158/0008-5472.CAN-21-1526 -
Clinical Cancer Research : An Official... Apr 2023In KATHERINE, adjuvant T-DM1 reduced risk of disease recurrence or death by 50% compared with trastuzumab in patients with residual invasive breast cancer after...
Biomarker Data from the Phase III KATHERINE Study of Adjuvant T-DM1 versus Trastuzumab for Residual Invasive Disease after Neoadjuvant Therapy for HER2-Positive Breast Cancer.
PURPOSE
In KATHERINE, adjuvant T-DM1 reduced risk of disease recurrence or death by 50% compared with trastuzumab in patients with residual invasive breast cancer after neoadjuvant therapy (NAT) comprised of HER2-targeted therapy and chemotherapy. This analysis aimed to identify biomarkers of response and differences in biomarker expression before and after NAT.
EXPERIMENTAL DESIGN
Exploratory analyses investigated the relationship between invasive disease-free survival (IDFS) and HER2 protein expression/gene amplification, PIK3CA hotspot mutations, and gene expression of HER2, PD-L1, CD8, predefined immune signatures, and Prediction Analysis of Microarray 50 intrinsic molecular subtypes, classified by Absolute Intrinsic Molecular Subtyping. HER2 expression on paired pre- and post-NAT samples was examined.
RESULTS
T-DM1 appeared to improve IDFS versus trastuzumab across most biomarker subgroups, except the HER2 focal expression subgroup. High versus low HER2 gene expression in residual disease was associated with worse outcomes with trastuzumab [HR, 2.02; 95% confidence interval (CI), 1.32-3.11], but IDFS with T-DM1 was independent of HER2 expression level (HR, 1.01; 95% CI, 0.56-1.83). Low PD-L1 gene expression in residual disease was associated with worse outcomes with trastuzumab (HR, 0.66; 95% CI, 0.44-1.00), but not T-DM1 (HR, 1.05; 95% CI, 0.59-1.87). PIK3CA mutations were not prognostic. Increased variability in HER2 expression was observed in post-NAT versus paired pre-NAT samples.
CONCLUSIONS
T-DM1 appears to overcome HER2 resistance. T-DM1 benefit does not appear dependent on immune activation, but these results do not rule out an influence of the tumor immune microenvironment on the degree of response.
Topics: Humans; Female; Trastuzumab; Breast Neoplasms; B7-H1 Antigen; Neoadjuvant Therapy; Receptor, ErbB-2; Neoplasm Recurrence, Local; Ado-Trastuzumab Emtansine; Antineoplastic Combined Chemotherapy Protocols; Tumor Microenvironment
PubMed: 36730339
DOI: 10.1158/1078-0432.CCR-22-1989 -
Journal of Clinical Oncology : Official... Apr 2017Purpose This phase I expansion cohort study evaluated the safety and clinical activity of mirvetuximab soravtansine (IMGN853), an antibody-drug conjugate consisting of a...
Safety and Activity of Mirvetuximab Soravtansine (IMGN853), a Folate Receptor Alpha-Targeting Antibody-Drug Conjugate, in Platinum-Resistant Ovarian, Fallopian Tube, or Primary Peritoneal Cancer: A Phase I Expansion Study.
Purpose This phase I expansion cohort study evaluated the safety and clinical activity of mirvetuximab soravtansine (IMGN853), an antibody-drug conjugate consisting of a humanized anti-folate receptor alpha (FRα) monoclonal antibody linked to the tubulin-disrupting maytansinoid DM4, in a population of patients with FRα-positive and platinum-resistant ovarian cancer. Patients and Methods Patients with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer received IMGN853 at 6.0 mg/kg (adjusted ideal body weight) once every 3 weeks. Eligibility included a minimum requirement of FRα positivity by immunohistochemistry (≥ 25% of tumor cells with at least 2+ staining intensity). Adverse events, tumor response (via Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1), and progression-free survival (PFS) were determined. Results Forty-six patients were enrolled. Adverse events were generally mild (≤ grade 2), with diarrhea (44%), blurred vision (41%), nausea (37%), and fatigue (30%) being the most commonly observed treatment-related toxicities. Grade 3 fatigue and hypotension were reported in two patients each (4%). For all evaluable patients, the confirmed objective response rate was 26%, including one complete and 11 partial responses, and the median PFS was 4.8 months. The median duration of response was 19.1 weeks. Notably, in the subset of patients who had received three or fewer prior lines of therapy (n = 23), an objective response rate of 39%, PFS of 6.7 months, and duration of response of 19.6 weeks were observed. Conclusion IMGN853 exhibited a manageable safety profile and was active in platinum-resistant ovarian cancer, with the strongest signals of efficacy observed in less heavily pretreated individuals. On the basis of these findings, the dose, schedule, and target population were identified for a phase III trial of IMGN853 monotherapy in patients with platinum-resistant disease.
Topics: Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Diarrhea; Disease-Free Survival; Drug Resistance, Neoplasm; Fallopian Tube Neoplasms; Fatigue; Female; Folate Receptor 1; Humans; Hypotension; Immunoconjugates; Maytansine; Middle Aged; Nausea; Ovarian Neoplasms; Peritoneal Neoplasms; Platinum Compounds; Response Evaluation Criteria in Solid Tumors; Retreatment; Vision Disorders
PubMed: 28029313
DOI: 10.1200/JCO.2016.69.9538 -
Cancer Cell Oct 2019We characterized the landscape and drug sensitivity of ERBB2 (HER2) mutations in cancers. In 11 datasets (n = 211,726), ERBB2 mutational hotspots varied across 25 tumor...
We characterized the landscape and drug sensitivity of ERBB2 (HER2) mutations in cancers. In 11 datasets (n = 211,726), ERBB2 mutational hotspots varied across 25 tumor types. Common HER2 mutants yielded differential sensitivities to eleven EGFR/HER2 tyrosine kinase inhibitors (TKIs) in vitro, and molecular dynamics simulations revealed that mutants with a reduced drug-binding pocket volume were associated with decreased affinity for larger TKIs. Overall, poziotinib was the most potent HER2 mutant-selective TKI tested. Phase II clinical testing in ERBB2 exon 20-mutant non-small cell lung cancer resulted in a confirmed objective response rate of 42% in the first 12 evaluable patients. In pre-clinical models, poziotinib upregulated HER2 cell-surface expression and potentiated the activity of T-DM1, resulting in complete tumor regression with combination treatment.
Topics: Ado-Trastuzumab Emtansine; Adult; Animals; Antineoplastic Agents, Immunological; Antineoplastic Combined Chemotherapy Protocols; DNA Mutational Analysis; Datasets as Topic; Disease Models, Animal; Drug Resistance, Neoplasm; Drug Synergism; Female; Humans; Male; Mice; Mice, Transgenic; Mutation; Neoplasms; Progression-Free Survival; Protein Kinase Inhibitors; Quinazolines; Receptor, ErbB-2
PubMed: 31588020
DOI: 10.1016/j.ccell.2019.09.001 -
Cancer Medicine Jun 2023The antibody-drug conjugate trastuzumab emtansine (T-DM1) is approved for human epidermal growth factor receptor 2 (HER2/ERBB2)-positive breast cancer. We aimed to study...
The antibody-drug conjugate trastuzumab emtansine (T-DM1) is approved for human epidermal growth factor receptor 2 (HER2/ERBB2)-positive breast cancer. We aimed to study tumor HER2 expression and its effects on T-DM1 responses in patients with HER2-positive urothelial bladder cancer (UBC) or pancreatic cancer (PC)/cholangiocarcinoma (CC). In the phase II KAMELEON study (NCT02999672), HER2 status was centrally assessed by immunohistochemistry, with positivity defined as non-focal homogeneous or heterogeneous overexpression of HER2 in ≥30% of stained cells. We also performed exploratory biomarker analyses (e.g., gene-protein assay) on tissue samples collected from study participants and consenting patients who failed screening. Of the 284 patients successfully screened for HER2 status (UBC, n = 69; PC/CC, n = 215), 13 with UBC, four with PC, and three with CC fulfilled eligibility criteria. Due to recruitment difficulty, the sponsor terminated KAMELEON prematurely. Of the five responders in the UBC cohort (overall response rate, 38.5%), HER2 expression was heterogeneous in two and homogeneous in three. The one responder in the PC/CC cohort had PC, and the tumor displayed homogeneous expression. In the biomarker-evaluable population, composed of screen-failed and enrolled patients, 24.3% (9/37), 1.5% (1/66), and 8.2% (4/49) of those with UBC, PC, or CC, respectively, had HER2-positive tumors. In a gene-protein assay combining in situ hybridization with immunohistochemistry, greater HER2 homogeneity was associated with increased ERBB2 amplification ratio. In conclusion, KAMELEON showed that some patients with HER2-positive UBC or PC can respond to T-DM1 and provided insight into the prevalence of HER2 positivity and expression patterns in three non-breast tumor types.
Topics: Humans; Female; Trastuzumab; Maytansine; Antibodies, Monoclonal, Humanized; Ado-Trastuzumab Emtansine; Receptor, ErbB-2; Breast Neoplasms; Cholangiocarcinoma; Carcinoma, Transitional Cell; Pancreatic Neoplasms; Urinary Bladder Neoplasms; Bile Duct Neoplasms; Bile Ducts, Intrahepatic
PubMed: 37119523
DOI: 10.1002/cam4.5893 -
Breast Cancer Research : BCR Jan 2023KRISTINE is an open-label, phase III study of trastuzumab emtansine + pertuzumab (T-DM1 + P) versus... (Randomized Controlled Trial)
Randomized Controlled Trial
Tumor biomarkers and efficacy in patients treated with trastuzumab emtansine + pertuzumab versus standard of care in HER2-positive early breast cancer: an open-label, phase III study (KRISTINE).
BACKGROUND
KRISTINE is an open-label, phase III study of trastuzumab emtansine + pertuzumab (T-DM1 + P) versus docetaxel + carboplatin + trastuzumab + pertuzumab (TCH + P) in patients with HER2-positive, stage II-III breast cancer. We investigated the association of biomarkers with clinical outcomes in KRISTINE.
METHODS
Patients were randomized to receive neoadjuvant T-DM1 + P or TCH + P and assessed for pathologic complete response (pCR; ypT0/is, ypN0). HER2 status (per central assessment), hormone receptor status, PIK3CA mutation status, HER2/HER3 mRNA levels, tumor-infiltrating lymphocyte levels, PD-L1 status, and NanoString data were analyzed. pCR rates by treatment arm were compared across biomarker subgroups. Analyses were descriptive.
RESULTS
Biomarker analyses included data from all 444 patients (T-DM1 + P, n = 223; TCH + P, n = 221) enrolled in KRISTINE. Biomarker distribution was balanced across treatment arms. All subgroups with higher HER2 amplification/expression and immune marker levels showed numerically higher pCR rates in both arms. Mutated versus non-mutated PIK3CA tumors were associated with numerically lower pCR rates in the T-DM1 + P arm but not in the TCH + P arm. In a multivariate analysis, Prediction Analysis of Microarray with the 50-gene classifier (PAM50) HER2-enriched subtype, HER2 gene ratio ≥ 4, and PD-L1-positive status positively influenced the pCR rate. Biomarkers associated with lower pCR rates (e.g., low HER2 levels, positive hormone receptor status, mutated PIK3CA) were more likely to co-occur. Dynamic on-treatment biomarker changes were observed. Differences in the treatment effects for T-DM1 + P versus TCH + P were similar to those observed in the intent-to-treat population for the majority of the biomarker subgroups.
CONCLUSIONS
Although our biomarker analysis did not identify a subgroup of patients that benefited from neoadjuvant T-DM1 + P versus TCH + P, the data revealed that patients with higher HER2 amplification/expression and immune marker levels had improved response irrespective of treatment arm. These analyses confirm the role of HER2 tumor biology and the immune microenvironment in influencing pCR in the neoadjuvant setting and reaffirm the molecular diversity of HER2-positive breast cancer.
TRIAL REGISTRATION
ClinicalTrials.gov NCT02131064. Registered 06 May 2014.
Topics: Female; Humans; Ado-Trastuzumab Emtansine; Antineoplastic Combined Chemotherapy Protocols; B7-H1 Antigen; Biomarkers, Tumor; Breast Neoplasms; Class I Phosphatidylinositol 3-Kinases; Neoadjuvant Therapy; Receptor, ErbB-2; Standard of Care; Trastuzumab; Tumor Microenvironment
PubMed: 36631725
DOI: 10.1186/s13058-022-01587-z