HER2 Gene Research Articles

HER2-low metastases of HER2-negative primary tumors: a single institution analysis of intertumoral and internodal heterogeneity in node-positive breast cancer.

HER2 status in breast cancer is an essential parameter in individual therapeutic decision-making and is routinely assessed in primary tumors in accordance with international recommendations. Reports of HER2 heterogeneity raise the question of basing treatment decisions on HER2 status in metastases, if present. We investigated the degree and clinical implications of HER2 heterogeneity in lymph node-positive breast cancer. Because of recent recognition of therapeutic opportunities in this group of tumors, we especially focused on cases involving low-level HER2 expression. The HER2 status of primary tumors and of corresponding lymph node metastases was determined in archived material at the protein and gene levels using the gene- protein assay and interpreted in accordance with 2018 ASCO/CAP criteria. HER2-low status was defined as protein expression levels 1+ or 2+ with negative amplification status. We analyzed a series of 43 cases of primary infiltrating breast cancer, each with at least two axillary nodes harboring macrometastases (>2 mm), in total 206 such nodes. In 7% of cases, we detected intertumoral HER2 heterogeneity. Three of nine HER2-positive primary tumors were associated with HER2-negative metastases. No cases with HER2-negative primary tumors had HER2-positive metastases, but 55% (6/11) of HER2 0 primary tumors had HER2 1+ and/or 2+ metastases, and 19% (3/16) HER2 1+ cases had exclusively HER2 0 metastases. All metastases in HER2 2+ cases showed HER2-low protein expression levels. Internodal HER2 heterogeneity at low protein expression levels (presence of HER2 0, HER2 1+, and/or HER2 2+ metastatic deposits within the same axilla) was seen in 40% (17/43) of cases. We found no statistically significant association between HER2 heterogeneity and other tumor-related parameters. Survival data indicated worse outcomes in the HER2-low group compared with the rest of the cohort. Our results indicate a substantial instability of HER2 protein expression, leading to considerable intertumoral and internodal HER2 heterogeneity in lymph node-positive breast carcinomas. This heterogeneity is particularly relevant in HER2-low tumors in which the corrective effects of HER2 gene copy number analysis definitionally is absent. Our findings suggest that determining HER2 status in metastatic lymph nodes may generate relevant information for therapeutic decision-making.

Fabrication, optimization, and characterization of pH-responsive PEGylated nanoniosomes containing gingerol for enhanced treatment of breast cancer.

Multiple potential drug delivery strategies have emerged as a result of recent advances in nanotechnology and nanomedicine. The aim of this research was to prepare an optimized system of PEGylated gingerol-loaded niosomes (Nio-Gin@PEG) as an excellent candidate for the treatment of human breast cancer cells. The preparation procedure was modified by adjusting the drug concentration, lipid content, and Span60/Tween60 ratio, resulting in high encapsulation efficacy (EE%), rapid release rate, and reduced size. The Nio-Gin@PEG exhibited significantly improved storage stability compared to the gingerol-loaded niosomes formulation (Nio-Gin), with minimal changes in EE%, release profile, and size during storage. Furthermore, Nio-Gin@PEG demonstrated pH-dependent release behavior, with delayed drug diffusion at physiological pH and significant drug diffusion under acidic conditions (pH = 5.4), making it a promising option for cancer treatment. Cytotoxicity tests indicated that Nio-Gin@PEG possessed excellent biocompatibility with human fibroblast cells while exerting a remarkable inhibitory effect on MCF-7 and SKBR3 breast cancer cells, attributed to the presence of gingerol and the PEGylated structure in the preparation. Nio-Gin@PEG also exhibited the ability to modulate the expression of target genes. We observed statistically significant down-regulation of the expression of BCL2, MMP2, MMP9, HER2, CCND1, CCNE1, BCL2, CDK4, and VEGF genes, along with up-regulation of the expression of BAX, CASP9, CASP3, and P21 genes. Flow cytometry results revealed that Nio-Gin@PEG could induce a higher rate of apoptosis in both cancerous cells compared to gingerol and Nio-Gin, owing to the optimal encapsulation and efficient drug release from the formulation, as confirmed by cell cycle tests. ROS generation demonstrated the superior antioxidant effect of Nio-Gin@PEG compared to other prepared formulations. The results of this study emphasize the potential of formulating highly biocompatible niosomes in the future of nanomedicine, enabling more precise and effective treatment of cancers.

Prevalence and clinicopathological associations of HER2 expression in non-small cell lung cancer: a retrospective study in Jordanian patients

BackgroundHuman epidermal growth factor receptor 2 (HER2), a promising therapeutic target, can be mutated, amplified, or overexpressed in different malignancies, including non-small cell lung cancer (NSCLC). Although these alterations showed adverse prognostic effects in many cancers, their clinical significance in NSCLC is controversial. This study primarily assessed the prevalence of HER2 protein expression in NSCLC among Jordanian patients. In addition, the possible association between HER2 protein expression and clinicopathological variables was evaluated.MethodsA total of 100 surgically resected NSCLC cases treated at King Hussein Cancer Center (KHCC) between 2009 and 2021 were examined for HER2 protein expression using immunohistochemistry (IHC). The American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines for breast cancer were applied to interpret the results with a final score ranging from 0 to 3+, considering a score of 3 + as overexpression. Additionally, a separate subset of patients was tested for HER2 gene mutation. Fisher’s exact test was used to assess the association between HER2 scores and the other variables. Kaplan-Meier method was used to calculate survival.ResultsOf the 100 cases, Her2 overexpression (score 3+) was detected in 2 cases (2%), score 2 + in 10 cases (10%), score 1 + in 12 cases (12%), and score 0 in 76 cases (76%). The two positive cases were one adenocarcinoma and one squamous cell carcinoma; both patients were elderly male smokers. No significant association was identified between Her2 expression and age, gender, smoking, histological subtype, grade, stage, tumor size, and lymph node status. Our findings also showed no association between Her2 expression and survival; however, advanced tumor stages and positive lymph node metastasis were significantly associated with poor overall survival. All cases tested for the Her2 mutation were negative.ConclusionsHer2 overexpression is uncommon in NSCLC among the Jordanian population. However, when the same scoring criteria are used, the rates are similar to other results found in Asian cohorts. Due to our study’s relatively small sample size, a larger one is required to investigate the prognostic value and the molecular associations between the different Her2 alterations.

Deep learning to automatically evaluate HER2 gene amplification status from fluorescence in situ hybridization images

Human epidermal growth factor receptor 2 (HER2) gene amplification helps identify breast cancer patients who may respond to targeted anti-HER2 therapy. This study aims to develop an automated method for quantifying HER2 fluorescence in situ hybridization (FISH) signals and improve the working efficiency of pathologists. An Aitrox artificial intelligence (AI) model based on deep learning was constructed, and a comparison between the AI model and traditional manual counting was performed. In total, 918 FISH images from 320 consecutive invasive breast cancers were analysed and automatically classified into 5 groups according to the 2018 ASCO/CAP guidelines. The overall classification accuracy was 85.33% (157/184) with a mean average precision of 0.735. In Group 5, the most common group, the consistency was as high as 95.90% (117/122), while the consistency was low in the other groups due to the limited number of cases. The causes of this inconsistency, including clustered HER2 signals, coarse CEP17 signals and some section quality problems, were analysed. The developed AI model is a reliable tool for evaluating HER2 amplification statuses, especially for breast cancer in Group 5; additional cases from multiple centres could further improve the accuracy achieved for other groups.

Angiogenesis inhibition in metastatic colorectal cancer continuum of care

Current treatment for most patients with metastatic colorectal cancer consists of sequential lines of different systemic therapies, including chemotherapy combinations (5-fluorouracil plus irinotecan or oxaliplatin) with the addition of molecular-targeted drugs, such as anti-angiogenic drugs (independently of the molecular characterisation of the tumour) or anti-epidermal growth factor receptor drugs (for patients whose tumours are wild type for KRAS and NRAS genes). More recently, for the subgroup of patients with high microsatellite instable or mismatch repair deficient tumours (approximately 5% of patients), immune checkpoint inhibitors (pembrolizumab or nivolumab plus ipilimumab) have been shown to be highly effective as first-line or second-line therapies. 1 Ciardiello F Ciardiello D Martini G Napolitano S Tabernero J Cervantes A Clinical management of metastatic colorectal cancer in the era of precision medicine. CA Cancer J Clin. 2022; 72: 372-401 Crossref PubMed Scopus (49) Google Scholar , 2 Cervantes A Adam R Roselló S et al. Metastatic colorectal cancer: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up. Ann Oncol. 2023; 34: 10-32 Summary Full Text Full Text PDF PubMed Scopus (70) Google Scholar Furthermore, in patients whose tumours show HER2 gene amplification, BRAFV600E mutation, or KRASG12C mutation, current treatment options also incorporate the corresponding appropriate molecular-targeted drugs. 1 Ciardiello F Ciardiello D Martini G Napolitano S Tabernero J Cervantes A Clinical management of metastatic colorectal cancer in the era of precision medicine. CA Cancer J Clin. 2022; 72: 372-401 Crossref PubMed Scopus (49) Google Scholar , 2 Cervantes A Adam R Roselló S et al. Metastatic colorectal cancer: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up. Ann Oncol. 2023; 34: 10-32 Summary Full Text Full Text PDF PubMed Scopus (70) Google Scholar Fruquintinib versus placebo in patients with refractory metastatic colorectal cancer (FRESCO-2): an international, multicentre, randomised, double-blind, phase 3 studyFruquintinib treatment resulted in a significant and clinically meaningful benefit in overall survival compared with placebo in patients with refractory metastatic colorectal cancer. These data support the use of fruquintinib as a global treatment option for patients with refractory metastatic colorectal cancer. Ongoing analysis of the quality of life data will further establish the clinical benefit of fruquintinib in this patient population. Full-Text PDF

HER2 Status Assessment in Endometrial Serous Carcinoma: Comparative Analysis of Two Proposed Testing and Interpretation Algorithms.

HER2 status is now routinely assessed in endometrial serous carcinoma (ESC) due to the reported predictive value of HER2 protein overexpression and/or gene amplification. Herein the authors compare 2 proposed testing and interpretation guidelines for HER2 in ESC. Forty-three consecutive cases of ESC that had been dually tested by both HER2 immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) were interpreted using 2 sets of guidelines. Guideline set 1 (GS1) is the 2018 American Society of Clinical Oncology/College of American Pathologists guidelines for breast cancer. Guideline set 2 (GS2) is a recent proposal that is a slight modification of the enrollment criteria for the clinical trial (NCT01367002) that demonstrated a survival benefit for anti-HER2 therapy in ESC. By IHC, GS1 and GS2, respectively classified 39.5% (17/43) and 28% (12/43) of ESC as HER2-negative, 37.2% (16/43) and 53.4% (23/43) as HER2 equivocal, and 23.2% (10/43) and 18.6% (8/43) as HER2-positive (P > 0.05 for all). IHC and FISH were highly concordant at the extremes using either set of guidelines, as no cases were found to be IHC3+/FISH-negative or IHC 0-1+/FISH-positive. GS1 and GS2 were comparable regarding the proportion of IHC equivocal cases that were HER2 amplified by FISH (19% vs 23% respectively; [P = 0.71]). GS1 and GS2 displayed 98% (42/43) concordance regarding the final (IHC and/or FISH-based) classification of tumors as being HER2-positive or negative, and the same 13 cases were ultimately classified as HER2 amplified using either GS1 or GS2. One "discordant" case was classified as HER2-positive using GS2 but HER2-negative using GS1 (HER2 IHC score 2+ using both guidelines, HER2:CEP17 signal ratio of 3, HER2 signal number of 3.4). Six (14%) of the 43 cases (FISH Groups: 2, 3, and 4) would require IHC results to interpret the FISH findings using GS1. Because GS1 requires that the HER2 IHC staining be observed within a homogeneous and contiguous invasive cell population, and this is not a requirement in GS2, GS2 may be better suited for ESC given its frequently heterogeneous staining pattern. Additional studies may be required on the optimal interpretation of problematic dual-probe FISH scenarios in GS2 and the necessity for IHC correlation in such scenarios. Using either set of guidelines, our findings support a reflex testing strategy of restricting FISH testing to cases that are IHC equivocal.

Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer.

To update the American Society of Clinical Oncology-College of American Pathologists (ASCO-CAP) recommendations for human epidermal growth factor receptor 2 (HER2) testing in breast cancer. An Update Panel is aware that a new generation of antibody-drug conjugates targeting the HER2 protein is active against breast cancers that lack protein overexpression or gene amplification. The Update Panel conducted a systematic literature review to identify signals for updating recommendations. The search identified 173 abstracts. Of 5 potential publications reviewed, none constituted a signal for revising existing recommendations. The 2018 ASCO-CAP recommendations for HER2 testing are affirmed. HER2 testing guidelines have focused on identifying HER2 protein overexpression or gene amplification in breast cancer to identify patients for therapies that disrupt HER2 signaling. This update acknowledges a new indication for trastuzumab deruxtecan when HER2 is not overexpressed or amplified but is immunohistochemistry (IHC) 1+ or 2+ without amplification by in situ hybridization. Clinical trial data on tumors that tested IHC 0 are limited (excluded from DESTINY-Breast04), and evidence is lacking that these cancers behave differently or do not respond similarly to newer HER2 antibody-drug conjugates. Although current data do not support a new IHC 0 versus 1+ prognostic or predictive threshold for response to trastuzumab deruxtecan, this threshold is now relevant because of the trial entry criteria that supported its new regulatory approval. Therefore, although it is premature to create new result categories of HER2 expression (eg, HER2-Low, HER2-Ultra-Low), best practices to distinguish IHC 0 from 1+ are now clinically relevant. This update affirms prior HER2 reporting recommendations and offers a new HER2 testing reporting comment to highlight the current relevance of IHC 0 versus 1+ results and best practice recommendations to distinguish these often subtle differences. Additional information is available at www.asco.org/breast-cancer-guidelines.

New Biomarkers and Treatment Advances in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is a specific subtype of breast cancer lacking hormone receptor expression and HER2 gene amplification. TNBC represents a heterogeneous subtype of breast cancer, characterized by poor prognosis, high invasiveness, high metastatic potential, and a tendency to relapse. In this review, the specific molecular subtypes and pathological aspects of triple-negative breast cancer are illustrated, with particular attention to the biomarker characteristics of TNBC, namely: regulators of cell proliferation and migration and angiogenesis, apoptosis-regulating proteins, regulators of DNA damage response, immune checkpoints, and epigenetic modifications. This paper also focuses on omics approaches to exploring TNBC, such as genomics to identify cancer-specific mutations, epigenomics to identify altered epigenetic landscapes in cancer cells, and transcriptomics to explore differential mRNA and protein expression. Moreover, updated neoadjuvant treatments for TNBC are also mentioned, underlining the role of immunotherapy and novel and targeted agents in the treatment of TNBC.

Incidence of hypomagnesemia in patients with HER2+ breast cancer treated with pertuzumab.

e12569 Background: Breast cancer is the most common cancer diagnosed in women. HER2 gene amplification/protein overexpression is seen in about 20% of breast cancer cases. Pertuzumab (P), an EGFR inhibitor, is a monoclonal antibody administered with Trastuzumab in the treatment of HER2-positive breast cancer. Breast oncologists across multiple institutions have noted hypomagnesemia in patients receiving P-containing regimens. Retrospective data from Memorial Sloan Kettering Cancer Center and University of Florida Health have reported the incidence of hypomagnesemia in patients treated with P neoadjuvantly (8/90 and 7/25, respectively). Cetuximab and Panitumumab, also EGFR inhibitors, are well known to cause hypomagnesemia. Hypomagnesemia can be clinically associated with convulsions, atrial tachycardias, hypocalcemia and hypokalemia. This prospective study details the incidence, severity, and timeline of hypomagnesemia in HER2-positive breast cancer patients treated with P. Methods: 27 eligible patients were identified at two institutions through medical oncology clinic visits and weekly tumor board screenings. Inclusion criteria was HER2+ breast cancer patients initiating treatment with P. Patients receiving platinum agents were excluded (8/27). Following informed consent, magnesium levels were obtained along with standard of care comprehensive metabolic panels at the first four P infusions (19/27). Results: A one-sample binomial test was used to compare the proportion of hypomagnesemia at 3 months among subjects who receive P with 2% (historical control). Results demonstrated that only one patient developed a magnesium level below normal range, resulting in no significant difference with historical control (P = 0.291) This patient’s magnesium level was low at baseline and did not significantly improve or worsen throughout treatment with P. Conclusions: There was no significant incidence of hypomagnesemia noted in HER2+ breast cancer patients treated with P. This emphasizes the safety of P in patient populations prone to developing hypomagnesemia such as those receiving concurrent Carboplatin. Our results do not indicate clinical monitoring of hypomagnesemia is necessary for patients receiving P. [Table: see text]

Pathological Types,Expression of Mismatch Repair Protein,Human Epidermal Growth Factor Receptor 2,and Pan-TRK,and Eostein-Barr Virus Infection in Patients With Colorectal Cancer Resected in Tibet

Objective To study the pathological types,expression of mismatch repair protein,human epidermal growth factor receptor 2(HER2),and Pan-TRK,and Epstein-Barr virus(EBV)infection in patients with colorectal cancer resected in Tibet. Methods A total of 79 patients with colorectal cancer resected in Tibet Autonomous Region People's Hospital from December 2013 to July 2021 were enrolled in this study.The clinical and pathological data of the patients were collected.The expression of mismatch repair protein,HER2,and Pan-TRK was detected by immunohistochemical(IHC)staining,and detection of HER2 gene by fluorescence in situ hybridization(FISH)in the patients with HER2 IHC results of 2+ or above.EBV was detected by in situ hybridization with EBV-encoded small RNA. Results A total of 79 colorectal cancer patients were included in this study,with the male-to-female ratio of 1.26:1 and the mean age of(57.06±12.74)years(24-83 years).Among them,4 patients received preoperative neoadjuvant therapy.Colonic cancer and rectal cancer occurred in 57(57/79,72.15%,including 31 and 26 in the right colon and left colon,respectively)and 22(22/79,27.85%)patients,respectively.The maximum diameter of tumor varied within the range of 1-20 cm,with the mean of(6.61±3.33)cm.Among the 79 colorectal cancer patients,75(75/79,94.94%)patients showed adenocarcinoma.Lymph node metastasis occurred in 12(12/21,57.14%)out of the 21 patients with severe tumor budding,13(13/23,56.52%)out of the 23 patients with moderate tumor budding,and 2(2/31,6.45%)out of the 31 patients with mild tumor budding,respectively.The lymph node metastasis rate showed differences between the patients with severe/moderate tumor budding and the patients with mild tumor budding(all P<0.001).The IHC staining showed that mismatch repair protein was negative in 10(10/65,15.38%)patients,including 5 patients with both MSH2 and MSH6 negative,4 patients with both MLH1 and PMS2 negative,and 1 patient with MSH6 negative.Pan-TRK was negative in 65 patients.The IHC results of HER2 showed 0 or 1+ in 60 patients and 2+ in 5 patients.FISH showed no positive signal in the 5 patients with HER2 IHC results of 2+.The detection with EBV-encoded small RNA showed positive result in 1(1/65,1.54%)patient. Conclusions Non-specific adenocarcinoma of the right colon is the most common in the patients with colorectal cancer resected in Tibet,and 15% of the patients showed mismatch repair protein defects.EBV-associated colorectal carcer is rare,Pan-TRK expression and HER2 gene amplification are seldom.The colorectal cancer patients with moderate and severe tumor budding are more likely to have lymph node metastasis.

Assessment of HER2 status in extramammary Paget disease and its implication for disitamab vedotin, a novel humanized anti-HER2 antibody-drug conjugate (ADC) therapy.

e21544 Background: Evaluation of HER2 status in extramammary Paget disease (EMPD) has been reported in a few studies with a small number of samples, and the HER2 overexpression rate ranges from 15% to 60%. The prognosis of advanced EMPD is poor and the treatment options is limited. Disitamab Vedotin (DV) is a novel humanized anti-HER2 antibody-drug conjugate (ADC), has been approved for metastatic urothelial carcinoma and gastric cancer in China. To determine the HER2 status and the efficacy of DV in advanced EMPD patients (pts) harboring HER2 expression, we conducted this multicenter retrospective study. Methods: Paraffin-embedded blocks, clinic-pathological data, and survival data of EMPD pts were retrospectively collected from 3 centers in China. HER2 IHC scoring and gene amplification evaluation were carried out according to the (ASCO/CAP) 2018 guidelines. The results of FISH and IHC were analyzed by two pathologists independently in a double-blinded manner. Data analysis was performed using SPSS v.26, Prism 8 and R version 3.6.5. Results: Finally, 129 cases with detailed data were enrolled between 2006 and 2022. Among them, HER2 IHC was performed in 102 cases, and FISH in 46 cases. HER2 expression was detected in 93.1% samples, with scores of 1+, 2+, and 3+ in 47.1% (48/102), 37.3% (38/102), and 8.7% (9/102) respectively. HER2 gene amplification was detected in eight cases (8/46, 17.4%), including all the cases with IHC 3+ (5/5, 100%), two with IHC 2+ (2/18, 11.1%), and one with IHC 1+ (1/22, 4.5%). For the subgroup of HER2 2+/3+, a higher frequency of lymph node metastasis (66.7% vs 33.3%, P = 0.034) and reduced survival time were detected than in HER2 1+/0. Two elderly male pts with advanced EMPD (one HER1+ /FISH-, one HER 2+/FISH-), who failed with chemo of paclitaxel, received 4 doses of DV infusion (2mg/kg every 2 weeks), and achieved partial responses both with tolerable toxicity. Conclusions: According to the study, the expression rate of HER-2 was very high in EMPD, indicating that it may be used as a routine treatment target. DV showed efficacy in these patients and need further validation.

Tissue-agnostic efficacy of trastuzumab deruxtecan (T-DXd) in advanced solid tumors with HER2 amplification identified by plasma cell-free DNA (cfDNA) testing: Results from a phase 2 basket trial (HERALD/EPOC1806).

3014 Background: HER2 ( ERBB2) gene amplification (amp) is a potential therapeutic target beyond breast and gastric cancers. HER2 amp can be detected in plasma cfDNA which may be an alternative to tissue biopsy. HERALD/EPOC1806 was a multicenter, investigator-initiated phase 2 trial of T-DXd for patients with HER2-amplified advanced solid tumors identified by cfDNA testing. Methods: We enrolled adults with advanced solid tumors harboring HER2 amp detected by next-generation sequencing of cfDNA (Guardant360) in the GOZILA study (UMIN000029315). We excluded breast or gastric cancer patients with HER2 overexpression (IHC 3+ or IHC 2+/ISH+). Patients received T-DXd 5.4 mg/kg every 3 weeks until disease progression or unacceptable toxicity. The primary endpoint was investigator-assessed objective response rate (ORR). Results: From December 2019 to January 2022, 4,734 patients were screened by cfDNA in the GOZILA study. Among 252 with HER2 amp, 62 with 16 cancer types were enrolled in HERALD. Median baseline plasma HER2 copy number (CN) was 8.55 (range, 2.4–73.9). All patients but 3 (all with salivary gland cancer) received prior anti-cancer therapy (median, 3 lines; range, 0–8). At a median follow-up of 8.9 months (data cut-off: July 17, 2022), the confirmed ORR was 56.5% (95% CI, 43.3–69.0%), statistically higher than the threshold value of 5%. Responses were observed for 13 cancer types, including KRAS-mutant colorectal (1/3), PIK3CA-mutant endometrial (5/6), and tissue HER2-negative gastric cancers (1/2). Plasma HER2 CN above vs. below the baseline median value did not impact response (ORR: 58.1% vs. 54.8%); however, the clearance vs. persistence of HER2 amp in cfDNA on Cycle 2 Day 1 corresponded to higher response (ORR: 88.0% vs. 22.7%). ORR by independent review was 58.1% (95% CI, 44.8–70.5%), and the disease control rate was 90.3% (95% CI, 80.1–96.4%). Median progression-free survival was 7.0 (95% CI, 4.9–9.7) months, and the median duration of response was 8.8 months (95% CI, 5.8–11.2). Most adverse events were mild to moderate. Interstitial lung diseases occurred in 16 patients (25.8%, G1/G2/G3; 14/1/1). Conclusions: T-DXd achieved a high ORR, durable response with a manageable safety profile in patients with advanced solid tumors and HER2 amp detected in cfDNA. Clinical trial information: JapicCTI-194707 .[Table: see text]

Afatinib in patients with recurrent/metastatic (RM) squamous cell carcinoma of the head and neck (SCCHN) harboring alterations in the HER pathway: Results of the B1 cohort of the EORTC-HNCG-1559 trial (UPSTREAM).

6034 Background: Afatinib (A) is an irreversible pan-HER inhibitor that improved PFS in second line RM SCCHN after platinum (LUX-H&amp;N1 trial). In a retrospective biomarker analysis, subgroups of pts with p16 negative, PTEN high or EGFR amplification SCCHN seem to benefit the most. Other studies suggest that A has activity in tumors with HER2 gene activation. Methods: The UPSTREAM trial is a biomarker-driven umbrella trial of targeted therapies and immunotherapy for RM SCCHN (post-platinum, ECOG 0-1, measurable disease). The B1 cohort was a phase II, randomized, open-label substudy evaluating the efficacy of afatinib (orally, 40mg/day) vs physician’s choice (ctrl) (2:1 ratio) in pts with p16 negative RM SCCHN harboring one of the following biomarkers (fresh biopsy): EGFR mutation(mut)/amplification(amp) or HER2 mut/amp or PTEN high by immunohistochemistry (IHC, H-score &gt; 150). Only KRAS/ HRAS/ NRAS wild type tumors were included. The primary endpoint was progression-free survival rate (PFSR) at 16 weeks after randomization. A 2-stage Simon optimal design was applied to arm A (H1 40%, H0 20%, 1-sided α 10%, power 90%) with 17 and 20 pts enrolled in the first and second stage respectively. Secondary endpoints included ORR, toxicity, PFS, and OS. Results: 59 RM SCCHN pts were included in the B1 cohort (A: n = 40, ctrl: n = 19). Out of the 59 patients, EGFR amp, HER2 amp and HER2 mut were found in 6 pts (10%), 1 pt (2%) and 1 pt (2%), respectively. PTEN (IHC) was high in 97%. 55 pts were evaluable (A: n = 38, ctrl: n = 17) (median age: 62, oral cavity: 29%, oropharynx: 36%, hypopharynx: 24%, larynx: 11%). 69% of pts had received ≥ 2 lines of systemic treatment for RM disease. 80% were pretreated with cetuximab. In arm A, 13/38 patients were alive and free of objective progression at 16 weeks (34.2%, 1-sided 90%CI, 23.9±inf), meeting the predefined criteria of success. The PFSR at 16W in ctrl arm was 29.4% (5/17). 4 objective responses were observed in arm A (3 PR and 1 CR) (ORR 11%, 95%CI 2.9-24.8%) and 1 PR in ctrl arm (6%). The median duration of response under A was 5.7 mo (range: 3.7-25.9 mo). All responding patients had previously been treated with cetuximab, were PTEN high but none had EGFR or HER2 alterations. The median PFS and OS were 2.2/2.4 mo and 7.2/5.0 mo in the A/ctrl arms, respectively. Grade ≥3 drug-related AEs were reported in 31% in arm A and 12% in ctrl arm. The most frequent drug-related AE with A were diarrhea (67%, G3:8%), rash (41%, G3: 3%), fatigue (31%, no G3) and mucositis (23%, G3: 3%). Conclusions: The B1 substudy met its primary endpoint of PFSR at 16 weeks. Responses were seen in cetuximab pre-treated pts. However, the clinical activity of A in this biomarker-selected population remains limited. Translational research is ongoing to better define potential biomarkers. Clinical trial information: NCT03088059 .

Correlation of HER2 low status in I-SPY2 with molecular subtype, response, and survival.

514 Background: HER2low, defined as immunohistochemical (IHC) 1+ or 2+ without HER2 gene amplification, predicted improved progression free and overall survival with trastuzumab deruxtecan (TDXd) compared to chemotherapy in patients (pts) with metastatic breast cancer in Destiny Breast04. Controversy exists regarding the correlation of HER2low with molecular subtypes and outcome. We evaluated these associations in the neoadjuvant ISPY2 trial. Methods: We investigated HER2 IHC class in pts with clinically HER2-negative breast cancer (BC) enrolled in the first 10 arms of ISPY2. To explore the biology of HER2low, we used Fisher’s exact test to assess association of IHC class (0 vs 1+ or 2+) with Response Predictive Subtypes-5 (RPS-5; based on immune, DNA repair damage (DRD), HER2, and luminal markers; PMID: 35623341), SET index [endocrine responsiveness], and Mammaprint high1 (MP1) vs high2 (MP2). Association with pathologic complete response (pCR) was assessed using Fisher’s exact test, and association with distant recurrence free survival (DRFS) was assessed using Cox Proportional Hazards modeling. Results: Of 742 HER2negative pts enrolled in the first 10 arms of ISPY2, local HER2 IHC is available for 585; 299 hormone receptor + (HR+) and 286 triple negative (TN). 63% of pts are HER2low, with HER2low status more frequent in HR+ (71%) compared to TN BC (55%; OR = 1.97; p = 0.00011). There was no clear relationship between HER2low IHC and RPS-5 subtypes or endocrine sensitivity measured by the SET index. There was no significant association of HER2low with pCR overall or within treatment arms (p &gt; 0.05); this was true for TN and HR+ subsets. 562 pts with HER2negative disease have distant recurrence free survival (DRFS) data with a median follow-up of 4.23 yrs. Pts with pCR had excellent outcome (5yr DRFS &gt; 94%), with no impact from HER2low vs 0 status. For pts with nonpCR, after adjusting for HR+ status, the DRFS hazard ratio for HER2low vs 0 status is not significant [0.68(0.46-1.02)]. Within HR+, HER2low is found in &gt; 70% for both SET low and high. HR+/MP1 pts (with generally low pCR rates) are significantly more likely to be HER2low (75%; (172/219)) compared to HR+/MP2 (61%; (49/80)) (OR: 1.79; Fisher p = 0.044). Importantly, 70% of HER2-Immune-/DRD- (78% HR+ and 56% TN), a subtype with low response to all ISPY2-tested agents, are HER2Low. Conclusions: In ISPY2 which enrolls patients with MP high risk BC, HER2low by IHC was frequent and higher in HR+ than TN disease. There was no clear association with molecular markers, pCR or DRFS. The frequency of HER2low in the immune-/DRD- subtype raises the potential for exploring T-DXd in this high risk, low-response setting. Clinical trial information: NCT01042379 .

Association of HER2/CEP17 ratio with pCR after HER2-directed neoadjuvant treatments in the phase III NeoALTTO trial.

600 Background: HER2-directed therapies are approved for the treatment of patients with HER2-positive invasive breast cancer as defined by HER2 protein overexpression, or HER2 gene amplification based on HER2/chromosome enumeration probe (CEP17) ratio ≥ 2.2. Above this accepted HER2 status determination, however, it is still unknown whether the efficacy of HER2-directed therapy in early breast cancer increases with increasing HER2/CEP17 ratios. Therefore, the purpose of the presented work is to evaluate whether quantitative assessment of the HER2/CEP17 ratio predicts pathological complete response (pCR) and event-free survival (EFS) of patients treated with neo-adjuvant HER2-based regimen in the prospective phase III NeoALTTO trial. Methods: 455 women with HER2-positive early breast cancer, who had received neo-adjuvant trastuzumab and/or lapatinib for 6 weeks and then together with 12 cycles of weekly paclitaxel were included in this analysis. The HER2/CEP17 ratio in the primary tumor samples was correlated with pCR and survival outcome. Results: The Median HER2/CEP17 ratio in NeoALTTO was 5.1 (range: 1.1 – 100.0), and ratios were not associated with age, hormone receptor status, or any of the other clinicopathological variables analyzed. The log HER2/CEP17 ratio significantly predicted for pCR in both uni-variate (OR: 1.83; 95% CI: 1.11 - 3.01, p = 0.0176) and multivariate analysis (OR: 1.79; 95% CI: 1.07 - 2.99, p = 0.0257). Higher HER2/CEP17 ratios were, however, not associated with improved EFS (adjusted HR = 0.79; p = 0.3537). A pCR prediction model which included HER2/CEP17 ratio, treatment arm, and hormone receptor status improved the predictive strength of treatment arm alone from a ROC AUC value of 0.60 to 0.69. Conclusions: In patients treated with HER2-based neoadjuvant therapy, quantitative analysis of the readily available pre-treatment HER2/CEP17 ratio by FISH is predictive of pCR but not EFS.

Clinicopathologic features of early stage HER2-low breast cancer.

e12545 Background: Breast cancer (BC) is the leading cause of cancer deaths in women worldwide. Traditionally, BC is divided into 3 categories: hormone receptor positive (HR+) if tumors overexpress either estrogen or progesterone receptors, HER2-positive (Pos) if tumors overexpress the human epidermal growth factor receptor protein (HER2), and triple negative if tumors lack overexpression of HER2, ER, or PR. 15% of all BC are HER2-Pos, which has poorer outcomes when compared to HER2-Neg. Early HER2 targeted therapies only showed benefit for treating tumors with high enough HER2 overexpression. Thus, HER2-Pos refers to tumors which stained 3+ for HER2 on immunohistochemistry (IHC) or 2+ with a positive result on amplification of the HER2 gene by fluorescence in-situ hybridization (FISH). In the recent DESTINY-Breast04 study, the drug trastuzumab deruxtecan showed benefit in treating metastatic BC patients with low levels of HER2 overexpression. HER2-Low, now a clinically relevant group, is defined as 1+ by IHC or 2+ and FISH negative. However, early stage HER2-Low BC is treated the same as HER2-Neg by the current standard of care. Large registry trials have described the HER2-Low patient population, mostly in the metastatic setting. Our study aims to describe the prevalence, pathological and clinical aspects of HER2-Low when compared to HER2-Neg BC in early stage BC patients within a community practice setting in the United States. Methods: This retrospective study analyzed 1,106 patients of which 120 were excluded due to being HER2-Pos. 986 HER2-Neg and HER2-Low patients of stages I-III were included. Patients had diagnosis dates between January 1st, 2015 and December 31st, 2022. Categorical and continuous analyses (two-proportion Z test) were performed to describe differences between HER2-Low and HER2-Neg patients at the time of diagnosis in age, tumor histology and grade, and need for chemotherapy. Results: 49% of patients (n = 1,106) were found to be HER2-Low. 91% of HER2-low patients were HR+, compared to 87% of HER2-Neg who were HR+ (p = 0.04). HER2-Low patients were more likely than HER2-Neg to have ductal carcinoma (82% vs. 75%, p = 0.01) and to be classified as grade 2 (58% vs. 48%, p = 0.001). The median age of patients with HER2-Low was 69 compared to 70 in patients with HER2-Neg disease. 36% of HER2-Low patients needed chemotherapy (neoadjuvant or adjuvant) compared to 35% who were HER2-Neg (p = 0.74). Conclusions: Our study revealed that HER2-Low patients were more likely than HER2-Neg patients to be HR+, grade 2, and to have ductal histology. In this early stage BC population, there was no difference in need for chemotherapy between HER2-Low and HER2-Neg patients. Future studies with a more racially diverse patient population looking at parameters of progression-free survival and overall survival in HER2-Low early stage BC population should be pursued.

Circulating tumor DNA (ctDNA) analyses in patients with HER2-positive biliary tract cancer (BTC) treated with trastuzumab deruxtecan (T-DXd): Exploratory results from the HERB trial.

4097 Background: In the phase 2 HERB trial (NCCH1805; JMA-IIA00423), T-DXd exhibited promising activity among patients with HER2-positive BTC (ASCO 2022 ab 4006). HER2 positivity was defined as tumor tissue immunohistochemistry (IHC) 3+ or IHC 2+ with in situ hybridization (ISH) positivity. HER2 gene amplification (HER2-amp) can also be detected in ctDNA, which may be an alternative when tumor tissue is not available. ctDNA may also detect tumor molecular changes during treatment and at disease progression. Methods: In this ancillary study, we collected plasma samples for ctDNA analysis (Guardant360) at baseline (BL), day 1 of cycle 2 (C2D1; ie, day 22 of treatment), and end of treatment (EOT). The relationships between clinical outcomes and ctDNA genomic profiles were evaluated. Results: Among the 30 patients in the full analysis set of HERB (22 with HER2-positive and 8 with HER2-low BTC), plasma samples for ctDNA were obtained from 30, 29, and 24 at BL, C2D1, and EOT, respectively. HER2-amp was found in ctDNA of 8 BL samples, all of which were from tissue HER2-positive patients. This included 50% (5 of 10) of the IHC 3+ tumors and 25% (3 of 12) of the IHC 2+/ISH + tumors. Comparing clinical outcomes for patients with HER2-amp in ctDNA (n=8) to those with HER2-positive in tissue (n=22), the confirmed objective response rate (cORR) was 50.0% (95% CI, 15.7–84.3), including all 2 CR cases, vs 36.4% (95% CI, 17.2–59.3); median duration of response was 7.9 (95% CI, 2.8–11.5) vs 7.4 months (95% CI, 2.8–NA), median progression-free survival (PFS) was 6.1 (95% CI, 2.8–20.3) vs 5.1 months (95% CI, 3.0–7.3), and median overall survival was 10.8 (95% CI, 4.7–NA) vs 7.1 months (95% CI, 4.7–14.6). Plasma copy number (median 5.1, range 2.3–9.9) was not associated with response or survival, even after adjusting for maximum variant allele frequency (MAF). Common BL genomic mutations found in ctDNA were in TP53 (n=19, 63%), PIK3CA (n=8, 27%), and TERT (n=7, 23%). No mutation was associated with treatment efficacy. Median MAF decreased from 7.3% at BL to 1.6% at C2D1. Decreased MAF was associated with better response (CR, PR, and SD) and longer PFS. Among 24 EOT samples, including 7 from patients with BL HER2-amp in ctDNA, 10 (42%) acquired potential resistance alterations, most related to receptor tyrosine kinase, MAPK, and PI3K pathways. HER2-amp was lost at EOT in 4 of the 7 patients with HER2-amp detected in BL ctDNA. Conclusions: Using a ctDNA assay, HER2-amp was detected in 36% of patients with tissue HER2-positive BTC. Those with HER2-amp in ctDNA than HER2-positive in tissue had potentially higher cORR and longer survival with TDXd. Clinical trial information: JMA-IIA00423 .

Efficacy and safety of KN026 in combination with KN046 in patients with locally advanced unresectable or metastatic HER2-positive other solid tumors.

3621 Background: Besides breast cancer (BC) and gastric cancer, HER2 is also widely expressed in other solid tumors, such as colorectal cancer (CRC), NSCLC, gallbladder cancer (GBC), renal pelvis cancer (RPC), pancreatic ductal adenocarcinoma (PDAC), etc. The reports of immunotherapy combined with HER2-targeted therapy are limited. KN026 is a novel bispecific antibody that simultaneously binds to two distinct HER2 epitopes. KN046 is a novel bispecific antibody that blocks both PD-L1 interaction with PD-1 and CTLA-4 interaction with CD80/CD86. Methods: KN026-203 study (NCT04521179) is an open-label, phase II, multi-center study to evaluate the efficacy and safety of KN026 (30mg/kg, Q3W, C1D1 and C1D8 loading) combined with KN046 (5mg/kg, Q3W) in patients (pts) with HER2-positive (defined as HER2 IHC 3+ or HER2 gene amplification) solid tumors. The study consisted of 3 cohorts, including HER2 positive gastric or gastroesophageal cancer (GC/GEJ), BC and other solid tumors. Pts received treatment until disease progression or unacceptable toxicity. Tumor assessments were scheduled every 6 weeks. The primary endpoints were ORR and DOR. The efficacy and safety of KN026 combined with KN046 were reported. Results: As of 10 November 2022, 26 pts with HER2 positive tumor other than BC and GC/GEJ were enrolled, including 15 CRC, 5 NSCLC, 4 GBC, 1 RPC and 1 PADC pts. All those pts had previous systemic treatment. The median age was 56 (range 37 ~ 67) years. 15 (57.7%) pts had liver metastasis. 92.3% of pts and all CRC pts had received ≥2 lines prior treatment. 5 (19.2%) and 6 (23.1%) pts had received prior anti-HER2 and anti-PD-(L)1 therapy, respectively. All 26 pts were assessed according to RECIST v1.1. The confirmed ORR was 53.8% (95% CI: 33.4, 73.4) with mDOR 6.8 months (95% CI: 2.9, 15.3). The mPFS was 5.6 months (95% CI: 2.9, 16.5) and 12-month OS rate was 80.4% (95% CI: 59.1, 91.4) with median follow-up time 16.6 months. For 15 CRC pts, the ORR was 53.3% (95% CI: 26.6, 78.7) with mDOR 11.7 months (95% CI: 3.2, NE). The mPFS was 12.2 months (95% CI: 2.7, NE) .12-month OS rate was 80.0% (95% CI: 50.0, 93.1) with median follow-up time 16.0 months. Common TRAEs were infusion related reaction (38.5%), AST increased (34.6%), ALT increased (26.9%), conjugated bilirubin increased (26.9%), rash (26.9%), anemia (26.9%) and blood bilirubin increased (26.9%). Most of them were Grade 1 or 2. The most common ≥ Gr3 TRAEs were conjugated bilirubin increased (7.7%) and AST increased (7.7%). There was no treatment related death. Conclusions: KN026 combined with KN046 treatment had demonstrated favorable efficacy and safety profile in HER2 positive other solid tumors (non-GC/GEJ and non-BC). Especially very promising efficacy were observed in ≥3 lines HER2 positive CRC. Based on these results, a pivotal study was planned to verify the efficacy and safety of KN026 and KN046 combo. Clinical trial information: NCT04521179 .

ECOG-ACRIN E2197: Comparison of HER2 gene expression by RT-PCR across all HER2 immunohistochemistry groups with recurrence analysis.

515 Background: Accurate assessment of HER2-low [immunohistochemical (IHC) score of 1+ or 2+ and in-situ hybridization negative] breast cancer is clinically relevant following DESTINY-Breast04. In hormone receptor positive breast cancers, Oncotype DX assay Recurrence Score results are widely used to guide adjuvant chemotherapy selection, and standardized quantitative HER2 mRNA reference-normalized expression levels by RT-PCR are included in patient reports. Previously, a high degree of concordance between central IHC and quantitative HER2 by RT-PCR was demonstrated in E2197. Here, we compare quantitative HER2 gene expression using Oncotype DX assay within all IHC subgroups and risk of recurrence in E2197. Methods: Data analyzed were from a case-control sample from E2197 (no adjuvant anti-HER2 therapy) of 755 patients. Central IHC for HER2 used duplicate 1.0 mm microarrays (HercepTest, Dako) and scored per 2007 ASCO/CAP guidelines. Based on quantitative reference-normalized RT-PCR measures of HER2 expression, cases were assigned: positive ≥11.5 units, equivocal ≥10.7 to &lt;11.5 units, and negative &lt;10.7 units (1 unit increase represents ~2-fold increase in RNA). Spearman’s rank correlation was used to measure strength of association between the 2 methods. Cox proportional hazards regression was used to evaluate the association between quantitative HER2 expression and recurrence (defined as invasive breast cancer in local, regional, or distant sites). Analyses were weighted to account for study design. Results: 48% were IHC 0, 11% were IHC 1+, 23% were IHC 2+, and 18% were IHC 3+. 85% were HER2 negative, 3% equivocal, and 11% positive by RT-PCR. While there was moderately strong correlation between HER2 IHC and HER2 gene expression by RT-PCR [Spearman’s rho: 0.63 (95% CI: 0.59, 0.67); p&lt;0.001], there were wide and overlapping ranges of HER2 gene expression across all IHC categories with almost identical medians and inter-quartile ranges for HER2 IHC 1+ and 2+ (n=248; see table). An exploratory analysis showed 86% of IHC 0, 97% of IHC 1+, and 99% of IHC 2+ had HER2 &gt;8 units. After controlling for baseline clinicopathologic features (age, hormone receptor status, grade, size, and nodal status), continuous quantitative HER2 expression was associated with time to recurrence in HER2 IHC 0 to 2+ [HR 1.17 per 1-unit increase in HER2 (95% CI 1.01, 1.35; p=0.036)]. Conclusions: There was a wide range of quantitative HER2 gene expression using Oncotype DX assay across all IHC categories; continuous HER2 expression is independently associated with recurrence. Quantitative HER2 expression may be useful for identification of HER2-low breast cancer. Further studies are needed. [Table: see text]

Negative selection of patients (pts) with HER2-positive and RAS wild-type (wt) metastatic colorectal cancer (mCRC) receiving dual HER2 blockade.

e15164 Background: Refining the selection of pts with HER2-positive mCRC for dual HER2 blockade is a challenge for precision oncology. Alterations in receptor tyrosin-kinase (RTK)/MAPK pathway and HER2 gene copy number (GCN) are promising predictive biomarkers for primary resistance or sensitivity, respectively. Methods: We conducted a multicentric case-control study to evaluate the negative predictive impact of a panel of candidate genomic alterations of primary resistance (PRESSING-HER panel) in pts with HER2-positive, RAS wt mCRC treated with trastuzumab-based dual HER2 blockade. Comprehensive genomic profiling was performed on archival pre-treatment tumor samples and screening sources were: the TRIUMPH trial (Oncomine Comprehensive Assay), the Italian-Spanish observational cohort (Foundation One CDx) and the MSKCC cohort (MSK-IMPACT). The panel grouped resistance alterations with a solid biological rationale as on-target, i.e. HER2 pathogenic mutations or rearrangements or off-target, i.e. mutations/amplifications in RTK/MAPK genes. Primary resistance was defined by PFS &lt; 4 months (mos), sensitivity was defined by PFS ≥4 mos. Hypothesizing a prevalence of PRESSING-HER alterations equal to 5% and 30% among controls and cases, respectively, 35 cases and 35 controls were needed to reject the null hypothesis of equally prevalent alterations, with α and β errors of 0.05 and 0.20. HER2 GCN was derived from NGS and the cut-off was calculated by ROC curve analyses using 4-month PFS rate as endpoint. Results: Sixty-eight pts were evaluable (33 resistant and 35 sensitive). In the overall population, PRESSING-HER alterations were found in 14 (20.6%) pts and included HER2 mutations in 7 (50%), HER2 rearrangements in 4 (29%), BRAF class 1 mutations in 2 (14%) and EGFR amplification in 1 (7%). PRESSING-HER alterations were significantly more frequent in pts with primary resistant (12/21, 57%) versus (vs) sensitive tumors (2/35, 6%; P= 0.004). HER2 GCN had a median value of 34.5 (IQR: 18.7-78.5) and an optimal cut-off of 33. In multivariable analyses including the main baseline clinical prognostic features, PRESSING-HER alterations were independently associated with inferior PFS (median PFS 2.0 vs 5.4 mos; adjusted HR 3.5, 95%CI 1.7-7.0; P&lt; 0.001) and OS (median OS 3.7 vs 14.8 mos; adjusted HR 3.9, 95%CI 1.8-8.3; P&lt; 0.001). HER2 GCN &lt; 33 was associated with significantly inferior median PFS (2.6 vs 5.4 mos; adjusted HR 1.8, 95%CI 1.0-3.1; P= 0.038) and numerically inferior OS (median OS 9.1 vs 15.4 mos; adjusted HR 1.3, 95%CI 0.7-2.5; P= 0.356). The predictive accuracy of PRESSING-HER was 66% and it was increased to 77% when combined with HER2 GCN. Conclusions: The combined assessment of HER2 on/off-target alterations and HER2 GCN stratifies patient outcomes to HER2 dual blockade.