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Background: UJVIRA is the first DCGI approved biosimilar of trastuzumab emtansine (Kadcyla) which may offer an alternative cost-effective treatment option for HER2-positive metastatic breast cancer patients in India. This article summarizes the available clinical evidence supporting the biosimilarity of UJVIRA and Kadcyla with respect to efficacy, pharmacokinetic, safety, and immunogenicity. Methods: A phase 3, randomized, open-label, active-controlled study was conducted at 31 sites across India. A total of 168 patients were enrolled and randomized to receive either UJVIRA or Kadcyla. Of which, only first 50 patients were included in pharmacokinetic assessment. UJVIRA or Kadcyla were administered at a dose of 3.6 mg/kg by intravenous infusion every 3 weeks (21 days) for 8 cycles or until disease progression or unmanageable toxicity, whichever was earlier. The study assessed efficacy (ORR), safety, pharmacokinetics, and immunogenicity. Results: The ORR at the end of Week 24 was 37.76% in the UJVIRA and 33.33% in the Kadcyla group. The risk difference was 4.42% [-12.01, 20.85]. It met non-inferiority margin of -15%. The pharmacokinetic parameters were comparable between groups. No anti-drug antibody was detected in any of the treatment groups. The overall safety profile in terms of TEAEs and laboratory abnormalities was also comparable between the treatment groups. Conclusion: Results demonstrated biosimilarity between UJVIRA and Kadcyla in terms of efficacy, safety, pharmacokinetics, and immunogenicity. Therefore, UJVIRA could prove to be a cost-effective treatment alternative for HER2-positive metastatic breast cancer patients in India.

Trastuzumab-induced cardiomyopathy is a known complication of its use in breast cancer treatment. However, cardiac complications of trastuzumab without left ventricular systolic dysfunction have been rarely reported. These include left bundle branch block, sinus node dysfunction, and ventricular tachycardia. We herein report a case of a 47-year-old female with human epidermal growth factor receptor 2-positive, stage IV breast cancer without a history of cardiovascular disease. During treatment with trastuzumab emtansine (T-DM1), she presented with out-of-hospital cardiac arrest and was resuscitated by automated cardioverter defibrillator (AED). Emergent cardiac catheterization revealed no organic obstruction and coronary vasospasm in her coronary arteries, and no left ventricular systolic dysfunction. Ventricular fibrillation (VF) was documented by an event memory of AED. T-DM1 was withdrawn and implantable cardioverter defibrillator was implanted. Thereafter, VF or life-threatening arrhythmia were not documented for 36 months until her death by breast cancer. We concluded that the etiology of her VF event was T-DM1-induced cardiotoxicity. We believe this is the first report of life-threatening VF event without cardiomyopathy induced by T-DM1.

Targeted therapies against human epidermal growth factor receptor 2 (HER2) are associated with increased interstitial lung disease (ILD). Trastuzumab, lapatinib, pertuzumab, and trastuzumab emtansine have markedly extended HER2 breast cancer survival but current knowledge on how these HER2-targeted agents induce interstitial lung disease is still poorly defined due to limited cases in the literature. Physicians mostly managed this complication by dose interruption, dose de-escalation, or discontinuation with success. In 2019, the FDA had granted accelerated approval on trastuzumab deruxtecan (T-Dxd) in HER2 breast cancer in the late line setting. Severe ILD incidence rate was over ten percent and led to fatal outcomes in 2.2% of patients in the T-Dxd trial. Searching for biomarkers to detect ILD incidence before it becomes clinically fulminant or for treatment response monitoring is of high clinical value. A Case of life-threatening trastuzumab-induced ILD was encountered in our facility. The ILD was confirmed to be antineutrophil cytoplasmic antibody (ANCA) pulmonary capillaritis. The biomarker of neutrophil extracellular traps (NETs), serum MPO-DNA complex, showed a good correlation with the clinical severity. Soon after B cell depleting agent rituximab usage, the serum MPO-DNA outperformed ANCA autoantibody and maintained its correlation with clinical severity. In addition to the trastuzumab-induced ILD case, a prospective cohort in our facility also confirmed the usefulness of MPO-DNA in monitoring vasculitis activity. We postulated that upfront testing with biomarkers of vasculitis during HER2 targeted treatment with high ILD incidence may be beneficial in the future., Graphical abstract Interaction Between Anti-HER2 Antibody and ANCA-Associated Vasculitis and Neutrophil In lung tissues, only bronchial epithelial cells express human epidermal growth factor 2 (HER2) protein in the cell surfaces. Once trastuzumab binds to the HER2 protein, trastuzumab acts as a stimulus to activate neutrophils to express autoantigen, including leukocyte proteinase 3 (PR3) and myeloperoxidase (MPO). The neutrophils could also directly release PR3 and MPO with cell-free DNA and histone through exocytosis to form a neutrophil extracellular trap (NETs). NETs containing PR3 and MPO could further trigger autoreactive B cells to produce ANCA antibodies, resulting in more neutrophil activation and alveolar-capillary endothelial as well as alveolar epithelial damage, although alveolar epithelial cells do not express HER2. A two-step mechanism explains how all previously reported cases that we identified manifests late with a median time of onset two months after the first trastuzumab exposure.Image 1, Highlights • Drug-induced Interstitial lung disease (DIILD) induced by HER2-targeted therapies, is a well-known adverse drug reaction, but the mechanism is ill-defined and no effective strategy for monitoring and prevention were reported. • We report a Case of trastuzumab-related interstitial lung disease induced by anti-neutrophil cytoplasmic antibody, which was never reported in previous literature. • As neutrophils dominate the inflammatory infiltrate in vasculitis, serum MPO-DNA, a biomarker of neutrophil activity, was performed in this Case and within a prospective vasculitis cohort in our facility and showed promising clinical severity correlation. • Monitoring with vasculitis-related autoantibodies and serum MPO-DNA may be helpful in future HER2-targeted agents since high rates of DIILD were reported due to this group of HER2-targeted agents.

Background Trastuzumab emtansine (T-DM1) is indicated as second-line treatment for human epidermal growth factor receptor 2 (HER2)-positive metastatic or unresectable locally advanced breast cancer, after progression on trastuzumab and a taxane-based chemotherapy. We wished to determine if the line of treatment in which T-DM1 is administered has an impact on progression-free survival (PFS) and in particular, if prior treatment with capecitabine/lapatinib or pertuzumab modifies PFS of further treatment with T-DM1. Patients and methods We performed a multicenter retrospective study in 3 Belgian institutions. We evaluated PFS with T-DM1 in patients treated for HER2 positive metastatic or locally advanced unresectable breast cancer between January 1, 2009 and December 31, 2016. Results We included 51 patients. The median PFS was 9.01 months. The line of treatment in which T-DM1 (1st line, 2nd line, 3rd line or 4+ lines) was administered had no influence on PFS (hazard ratio 0.979, CI95: 0.835–1.143). There was no significant difference in PFS whether or not patients had received prior treatment with capecitabine/lapatinib (9.17 vs 5.56 months, p-value 0.875). But, patients who received pertuzumab before T-DM1 tended to exhibit a shorter PFS (3.55 months for T-DM1 after pertuzumab vs 9.50 months for T-DM1 without pretreatment with pertuzumab), even if this difference was not statistically significant (p-value 0.144). Conclusion Unlike with conventional chemotherapy, the line of treatment in which T-DM1 is administered does not influence PFS in our cohort of patients with advanced HER2-positive breast cancer.

HER2 is a predictive biomarker for HER2-targeted therapeutics. For antibody–drug conjugates (ADCs; e.g., trastuzumab emtansine (T-DM1)), HER2 is utilized as a transport gate for cytotoxic agents into the cell. ADC biomarkers may therefore be more complex, also reflecting the intracellular drug transport. Here we report on a positive correlation between the early endosome marker RAB5A and T-DM1 sensitivity in five HER2-positive cell lines. Correlation between RAB5A expression and T-DM1 sensitivity is confirmed in breast cancer patients treated with trastuzumab emtansine/pertuzumab in the I-SPY2 trial (NCT01042379), but not in the trastuzumab/paclitaxel control arm. The clinical correlation is further verified in patients from the KAMILLA trial (NCT01702571). In conclusion, our results suggest RAB5A as a predictive biomarker for T-DM1 response and outline proteins involved in endocytic trafficking as predictive biomarkers for ADCs., Antibody Drug Conjugates (ADCs) are emerging in the field of precision cancer medicine. Here, the authors suggest using endocytosis as a predictive biomarker for response

Human epidermal growth factor receptor 2 (HER2) is a proto-oncogene that, when mutated or overexpressed, plays an important role in oncogenesis. The landscape of HER2-positive breast cancer has changed dramatically over the past 2 decades with the FDA approval of a growing number of agents (antibodies, tyrosine kinase inhibitors, and antibody-drug conjugates) targeting the HER2 receptor. HER2 inhibition has also been approved for HER2-positive gastric cancer. HER2 is amplified in 9% and mutated in 3% of lung cancer. Historically, HER2-targeted therapy for lung cancer with trastuzumab, pertuzumab, and trastuzumab emtansine has failed to demonstrate a survival benefit. Trastuzumab deruxtecan (T-DXd) is a novel antibody-drug conjugate with a tetrapeptide linker, which delivers a topoisomerase I inhibitor with a drug-to-antibody ratio of 7~8. The potency of the active payload, as well as its significant bystander effect, resulted in significant anti-tumor activity. The DESTINY-Lung01 trial evaluated T-DXd in HER2-positive non-squamous non-small cell lung cancer (NSCLC) and reported a progression-free survival of 14 months in HER2-mutated NSCLC, earning its breakthrough designation by the FDA. In this review, we will discuss the structural characteristics, pharmacodynamics, and pharmacokinetics of T-DXd. We will also shed light on the preclinical and ongoing clinical trials of T-DXd along with future directions in the management of HER2 positive lung cancer.

This is a summary of the article discussing the results of the DESTINY-Breast01 study originally published in the New England Journal of Medicine. The DESTINY-Breast01 study is a clinical study in participants with a type of breast cancer called HER2-positive breast cancer. The participants in the study received a treatment called trastuzumab deruxtecan, also known as T-DXd. The purpose of this summary is to help you understand the results of the DESTINY-Breast01 study. T-DXd is currently available as a treatment for adults with HER2-positive breast cancer that cannot be removed by surgery, also called unresectable, or that has spread, also called metastatic. In the DESTINY-Breast01 study, all the participants had HER2-positive breast cancer that was metastatic or unresectable. All participants were required to have had previous treatment for their HER2-positive breast cancer with another treatment, called trastuzumab emtansine or T-DM1. All the participants received T-DXd every 3 weeks. Part 1 was done to learn how T-DXd acted in the body, and to choose a dose to give to all the participants in Part 2. In Part 2, 184 participants received T-DXd at 5.4 mg/kg and the results showed that T-DXd reduced tumor growth. Up to 60.9% of the participants had their tumors shrink or disappear, with a treatment response that lasted for nearly 15 months on average. The participants lived with their cancer for around 16 months before it got worse. During the study, 183 out of 184 participants had side effects, known as adverse events. The most common adverse event was nausea. There were 42 participants (22.8%) who had serious adverse events, including lung toxicity. These results suggest that T-DXd could be a treatment option for people with metastatic HER2-positive breast cancer who have already been treated with T-DM1. Additional studies will provide more information and results about T-DXd. ClinicalTrials.gov NCT number: NCT03248492. To read the full Plain Language Summary of this article, click on the View Article button above and download the PDF. Link to original article here .

Pharmacological therapy targeting the HER2 protein is one of the major breakthroughs in the treatment of cancer patients overexpressing HER2 who have increased survival rates. Despite improved survival, it is important to determine the less frequent adverse effects in order to tailor treatments more personalized to the patients’ features. The possible impact of cancer treatments on cognitive functions is huge, and the effects of anti-HER 2 therapies on this issue have not been reviewed and are the objective of this study. Analysis of PubMed, Scopus, Cochrane library and Web of Science databases revealed six studies performed in breast and serous uterine cancer patients analyzing cognitive function under chemotherapy regimens including anti-HER2 drugs. Four of these studies reported small to significant worsening of cognitive function following chemotherapy regimens containing trastuzumab (the most widely used anti-HER2 drug). In neoadjuvant settings, and in breast cancer patients, treatment with the new anti-HER-2 drug trastuzumab emtansine seems to induce less cognitive impairment than therapeutic regimens containing chemotherapy and trastuzumab. Acute administration of trastuzumab induced cognitive impairment in gastric cancer mice models, confirming its ability to alter cognitive function in patients. More studies analyzing the impact of anti-HER2 therapy on cognitive function are necessary at preclinical and clinical levels in order to personalize pharmacological treatment and offer cancer patients a better quality of life.

Background In the KATHERINE study (NCT01772472), patients with residual invasive early breast cancer (EBC) after neoadjuvant chemotherapy (NACT) plus human epidermal growth factor receptor 2 (HER2)-targeted therapy had a 50% reduction in risk of recurrence or death with adjuvant trastuzumab emtansine (T-DM1) versus trastuzumab. Here, we present additional exploratory safety and efficacy analyses. Patients and methods KATHERINE enrolled HER2-positive EBC patients with residual invasive disease in the breast/axilla at surgery after NACT containing a taxane (± anthracycline, ± platinum) and trastuzumab (± pertuzumab). Patients were randomized to adjuvant T-DM1 (n = 743) or trastuzumab (n = 743) for 14 cycles. The primary endpoint was invasive disease-free survival (IDFS). Results The incidence of peripheral neuropathy (PN) was similar regardless of neoadjuvant taxane type. Irrespective of treatment arm, baseline PN was associated with longer PN duration (median, 105-109 days longer) and lower resolution rate (∼65% versus ∼82%). Prior platinum therapy was associated with more grade 3-4 thrombocytopenia in the T-DM1 arm (13.5% versus 3.8%), but there was no grade ≥3 hemorrhage in these patients. Risk of recurrence or death was decreased with T-DM1 versus trastuzumab in patients who received anthracycline-based NACT [hazard ratio (HR) = 0.51; 95% confidence interval (CI): 0.38-0.67], non-anthracycline-based NACT (HR = 0.43; 95% CI: 0.22-0.82), presented with cT1, cN0 tumors (0 versus 6 IDFS events), or had particularly high-risk tumors (HRs ranged from 0.43 to 0.72). The central nervous system (CNS) was more often the site of first recurrence in the T-DM1 arm (5.9% versus 4.3%), but T-DM1 was not associated with a difference in overall risk of CNS recurrence. Conclusions T-DM1 provides clinical benefit across patient subgroups, including small tumors and particularly high-risk tumors and does not increase the overall risk of CNS recurrence. NACT type had a minimal impact on safety.

Introduction Salivary gland neoplasms (SGNs) respond poorly to the traditional chemotherapy agents limiting the availability of systemic treatment options in the metastatic setting. The recent identification of actionable molecular targets in SGNs has led to the evaluation of targeted therapies in non-approved advanced SGNs. Case Report We present the case of an elderly male with HER-2 Neu overexpressing metastatic mucoepidermoid carcinoma (MEC) who demonstrated a prompt and sustained disease response to targeted therapies directed against HER-2 Neu with long survival interrupted by hepatoxicity to Trastuzumab emtansine (TDM-1) treatment. Management and Outcome: The patient was started on Trastuzumab and Pertuzumab on a clinical trial and resulted in an objective improvement sustained over 3 years. Following the disease progression, TDM-1 was started with a response until the patient developed severe hepatotoxicity as an adverse effect of TDM-1 therapy resulting in its discontinuation. Close follow-up post-treatment-discontinuation demonstrated continued clinical improvement until 6 months, when the patient developed brain metastasis. He passed away a few months later in hospice care. Discussion The metastatic MEC in our patient overexpressed HER-2 Neu. Owing to Trastuzumab and Pertuzumab response, Trastuzumab emtansine (TDM-1) was initiated on a compassionate basis which further extended the survival but had to be terminated owing to adverse effects. Given the paucity of data on targeted therapies in the treatment of metastatic SGNs and the safety, tolerability, and efficacy of TDM-1 therapy among the elderly, further studies are warranted to answer these important questions and to identify eligible patients for this novel treatment option.

Trastuzumab emtansine (T-DM1) is a human epidermal growth factor receptor 2 (Her2) - targeted antibody-drug conjugate that is approved for patients previously treated with trastuzumab and a taxane for Her2-positive advanced breast cancer and those who have progressed within 6 months of completion of adjuvant chemotherapy, as well as for patients with residual invasive Her2-positive disease after the completion of adjuvant chemotherapy. Peripheral neuropathy is a common adverse event; however, ocular events have also been described. With the current report we present the case of a 67-year old woman who developed transient grade 2-3 blurred vision after the first T-DM1 infusion, which was complicated with grade 2 diplopia causing vertigo after the second infusion. After extended investigation, this symptomatology was attributed to central neurotoxicity, and gradually resolved after T-DM1 discontinuation.

The standard first-line treatment for patients with human epidermal growth factor 2-positive metastatic breast cancer is a combination therapy of trastuzumab, pertuzumab and docetaxel, and the standard second-line treatment is trastuzumab emtansine. However, it may be difficult for the elderly to maintain sufficient intensity of treatment due to severe adverse events of trastuzumab, pertuzumab and docetaxel. The aim of this trial is to confirm the non-inferiority of trastuzumab emtansine over trastuzumab, pertuzumab and docetaxel in terms of overall survival in elderly (65-year-old or more) patients with human epidermal growth factor 2-positive metastatic breast cancer. If improved overall survival and fewer toxicities are observed, trastuzumab emtansine may be a feasible new standard first-line treatment for elderly patients with human epidermal growth factor 2-positive metastatic breast cancer. A planned total 330 patients will be enrolled from 45 institutions over 6.5 years. This trial has been registered in the UMIN Clinical Trials Registry as UMIN000030783 [http://www.umin.ac.jp/ctr/index.htm].

Descripton of metastatic HER2-positive breast cancer clinical case is introduced, multilineal strategy basing on clinical situation and disease features is justified, justification of the choice of anti-HER2 treatment in every line is made, in compliance with russian and foreigh oncology associations guidelines, along with comparance of rutine treatment results and randomised trials data.

Introduction Advanced breast cancer (aBC) remains incurable and the quest for more effective systemic anticancer agents continues. Promising results have led to the FDA approval of three antibody-drug conjugates (ADCs) and two immune checkpoint inhibitors (ICIs) to date for patients with aBC. Areas covered With the anticipated emergence of newer ADCs and ICIs for patients with several subtypes of breast cancer, and given their potential synergy, their use in combination is of clinical interest. In this article, we review the use of ADCs and ICIs in patients with breast cancer, assess the scientific rationale for their combination, and provide an overview of ongoing trials and some early efficacy and safety results of such dual therapy. Expert opinion Improvement in the medicinal chemistry of next-generation ADCs, their rational combination with ICIs and other agents, and the development of multiparametric immune biomarkers could help to significantly improve the outlook for patients with refractory aBC.

Despite great success as a targeted breast cancer therapy, trastuzumab use may be complicated by heart failure and loss of left ventricular contractile function. This review summarizes the risk factors, imaging, and prevention of cardiotoxicity associated with trastuzumab and other HER2-targeted therapies. Cardiovascular disease risk factors, advanced age, and previous anthracycline treatment predispose to trastuzumab-induced cardiotoxicity (TIC), with anthracycline exposure being the most significant risk factor. Cardiac biomarkers such as troponins and pro-BNP and imaging assessments such as echocardiogram before and during trastuzumab therapy may help in early identification of TIC. Initiation of beta-adrenergic antagonists and angiotensin converting enzyme inhibitors may prevent TIC. Cardiotoxicity rates of other HER2-targeted treatments, such as pertuzumab, T-DM1, lapatinib, neratinib, tucatinib, trastuzumab deruxtecan, and margetuximab, appear to be significantly lower as reported in the pivotal trials which led to their approval. Risk assessment for TIC should include cardiac imaging assessment and should incorporate prior anthracycline use, the strongest risk factor for TIC. Screening and prediction of cardiotoxicity, referral to a cardio-oncology specialist, and initiation of effective prophylactic therapy may all improve prognosis in patients receiving HER2-directed therapy. Beta blockers and ACE inhibitors appear to mitigate risk of TIC. Anthracycline-free regimens have been proven to be efficacious in early HER2-positive breast cancer and should now be considered the standard of care for early HER2-positive breast cancer. Newer HER2-directed therapies appear to have significantly lower cardiotoxicity compared to trastuzumab, but trials are needed in patients who have experienced TIC and patients with pre-existing cardiac dysfunction.

Aim: The aim of this study is to evaluate the efficacy and toxicity of trastuzumab emtansine (T-DM1) in cases with metastatic breast cancer (mBC) in different lines of treatment. Method: Retrospective analysis of T-DM1 results of human epidermal growth factor receptor 2 (Her2) positive 414 cases with mBC from 31 centers in Turkey. Findings: Except 2, all of the cases were female with a median age of 47. T-DM1 had been used as second-line therapy in 37.7% of the cases and the median number of T-DM1 cycles was 9. Progression-free survival (PFS) and overall survival (OS) times were different according to the line of treatment. The median OS was found as 43, 41, 46, 23 and 17 months for 1st, 2nd, 3rd, 4th and 5th line, respectively (p = 0.032) while the median PFS was found as 37, 12, 8, 8 and 8 months, respectively (p = 0.0001). Treatment was well tolerated by the patients. The most common grade 3–4 adverse effects were thrombocytopenia (2.7%) and increased serum gamma-glutamyl transferase (2%). Discussion: The best of our knowledge this is the largest real-life experience about the safety and efficacy of T-DM1 use in cases with mBC after progression of Her2 targeted treatment. This study suggests and supports that T-DM1 is more effective in earlier lines of treatment and is a reliable option for mBC. © 2021 Taylor & Francis Group, LLC.

In the care of patients with operable breast cancer, there has been a shift toward increasing use of neoadjuvant therapy. There are benefits to neoadjuvant therapy, such as monitoring for response, as well as an increased rate of breast conservation and reduction of potential morbidity associated with breast surgery, including axillary management. Among patients with highly proliferative tumors, such as HER2-positive or triple-negative breast cancer, those with residual disease are at higher risk of recurrence, which informs the recommended systemic therapy in the adjuvant setting. For instance, in patients with residual disease after neoadjuvant chemotherapy and HER2-targeted therapy, there is a role for adjuvant trastuzumab emtansine for those with residual disease at the time of surgery. The same holds true regarding the role of adjuvant capecitabine in patients with residual disease after neoadjuvant chemotherapy. With the added complexities of treating patients in the era of the COVID-19 outbreak, additional considerations are critical, including initiation of surgery within an appropriate time from completion of neoadjuvant therapy. National consensus guidelines on time to surgery must be developed to improve measurement and comparison across systems. In addition, there is emerging radiation treatment management research addressing a number of factors, including hypofractionation, role of proton beam therapy, safe omission of radiotherapy, and preoperative radiotherapy with or without drug combination. In this article, the multidisciplinary approach of treating patients with operable breast cancer is highlighted, with updates and future considerations described.

Human epidermal growth factor receptor 2 (HER2), as a receptor tyrosine kinase of EGF receptor family, whose mutation is often associated with even if less frequency but poor prognosis and shorter survival in pulmonary malignant tumor. HER2 status include mutation, overexpression, amplification and also some rare genotypes, detected by next generation sequencing (NGS), immunohistochemistry (IHC), and also fluorescence in situ hybridization (FISH). Different genotypes represent different therapeutic targets and indicate different clinical prognosis concluded by previous studies. Unfortunately, no standard guidelines for first-line treatment are widely recognized, and current therapeutic schedules include chemotherapy, radiotherapy, targeted therapy, and immunotherapy. Especially for patients with advanced metastasis, chemotherapy is based as a systemic therapy using studies of breast cancer or EGFR-positive lung adenocarcinoma as a template. Studies already explored treatment including EGFR tyrosine kinase inhibitors (TKIs) such as gefitinib and afatinib, and also trastuzumab and its conjugation like HER2-targeted antibody-drug conjugate trastuzumab emtansine (T-DM1) and conjugate trastuzumab deruxtecan (T-DXd). Also, he researches explored combination therapy with chemotherapy and TKIs or monoclonal antibodies. This review describes commonly used therapies for HER2-positive/HER2-overexpression patients and general relationship between genotypes of HER2, drug selection and final prognosis in order to provide suggestions for future diagnosis and treatment.

The article discusses modern approaches in the treatment of HER2-positive breast cancer (BC) with brain metastases (BM).The patients are subject to multidisciplinary, comprehensive and biologically – oriented treatment, with the involvement of a neurosurgeon and a radiation therapist to make a decision considering local treatment of BM, as well as a clinical oncologist to choose systemic drug therapy. Local treatment of HER2+ BC with BM patients includes surgical treatment and/or radiotherapy. Use of targeted anti-HER2 therapy changes “biology” of the disease from aggressive to indolent.In the prospective KAMILLA trial, clinically significant antitumor activity of trastuzumab emtansine was found for the first time both in patients with HER2+ BC with BM, who were previously treated with radiotherapy, and without radiotherapy in the anamnesis, which suggests the validity of further use of trastuzumab emtansine in this category of patients.The antitumor activity of trastuzumab emtansine in patients with HER2+ BC with BM was also confirmed in preclinical models. Despite the similar drug distribution in the tissues, trastuzumab emtansine, in contrast to trastuzumab, significantly slowed the growth of metastases, causing the induction of apoptosis in HER2+ BC models with BM in mice.

Trastuzumab emtansine (T-DM1) is an antibody drug conjugate used to treat HER2-positive breast cancer. We hypothesized that functional imaging with 64Cu-DOTA-trastuzumab PET/CT would predict patient response to T-DM1 therapy. Methods: Ten women with biopsy-proven HER2-positive metastatic breast cancer who were to be treated with T-DM1 underwent pretreatment 18F-FDG PET/CT. 64Cu-DOTA-trastuzumab PET/CT was performed 1 and 2 days post-injection. Treatment outcome was assessed by (a) response to T-DM1 (3.6 mg/kg every 3 wk) as evaluated by follow-up 18F-FDG PET/CT using PERCIST criteria and (b) time to treatment failure (TTF). Tumors measurable for response were evaluated for 64Cu-DOTA-trastuzumab uptake in terms of maximum voxel standardized uptake value (SUVmax, units g/mL). Results: Response was clearly related to tumor uptake of 64Cu-DOTA-trastuzumab. Comparing group means, responsive patients (n = 5) had higher day 1 minimum SUVmax (5.6 vs 2.8, P threshold (P < 0.01). Patients with day 2 minimum SUVmax above versus below threshold had median TTF = 28 months versus 2 months (P < 0.02).

Introduction Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate which combine trastuzumab (T), a monoclonal antibody targeting the human epidermal growth factor receptor-2 (HER2), and a cytotoxic molecule derived from maytansine (DM1). Case report We report the first case of T-DM1-associated pleural and pericardial effusions three weeks after the second course of T-DM1 in a patient with breast cancer. Drug-induced pleural and pericardial effusions was implicated in the absence of other etiologies. The Naranjo Scale indicated a probable drug-induced adverse reaction. Management & outcome: The patient fully recovered after thoracentesis and discontinuation of T-DM1. The patient has reported no side effect after the sixth course of trastuzumab. Discussion To our knowledge, this is the first case in the literature of bilateral pleural and pericardial effusions in a patient treated with T-DM1. The successful initiation of treatment with trastuzumab following withdrawal of T-DM1 suggests that emtansine played a role in the development of bilateral pleural and pericardial effusions. We hypothesize that the patient’s condition was a result of a local inflammatory reaction to emtansine by direct toxicity.

Aim: To investigate the comparative effectiveness of trastuzumab emtansine (T-DM1) in a real-world population of HER2+ metastatic breast cancer (mBC) patients. Materials & methods: The Flatiron Health database was used to identify a cohort of HER2+ mBC patients who received first-line trastuzumab treatment and T-DM1 or lapatinib plus chemotherapy as second-line treatment. Overall survival was compared between the two groups. Results: A total of 278 patients with HER2+ mBC received second-line T-DM1 and 34 lapatinib plus chemotherapy. Overall survival was longer in patients treated with T-DM1 than those treated with lapatinib plus chemotherapy (adjusted hazard ratio: 0.56; 95% CI: 0.38–0.85). Conclusion: Real-world data supports the effectiveness of T-DM1 in the second-line treatment of HER2+ mBC patients.

In the KATHERINE study (NCT01772472), patients with HER2-positive early breast cancer (EBC) and residual invasive disease after neoadjuvant chemotherapy plus HER2-targeted therapy who were treated with adjuvant trastuzumab emtansine (T-DM1) had a 50% reduction in the risk of an invasive disease-free survival (IDFS) event compared to patients treated with adjuvant trastuzumab. In metastatic disease, T-DM1 has resulted in higher rates of thrombocytopenia in Asian versus non-Asian patients. Here, we report safety and efficacy in Chinese patients from KATHERINE. Patients with HER2-positive EBC and residual invasive disease after taxane- and trastuzumab-containing neoadjuvant chemotherapy followed by surgery were randomized 1:1 to 14 cycles of adjuvant T-DM1 or trastuzumab. The primary endpoint was time to an IDFS event. Among Chinese patients (T-DM1 n = 51, trastuzumab n = 50), T-DM1 treatment resulted in a 43% reduction in risk of an IDFS event compared to trastuzumab (HR = 0.57; 95% CI 0.25–1.31), with similar results for secondary endpoints. As in the global population, Chinese patients receiving T-DM1 versus trastuzumab had more grade ≥ 3 adverse events (AEs; 39.2% versus 4.1%) and AEs leading to treatment discontinuation (27.5% versus 0%). The most common grade ≥ 3 AE with T-DM1 was thrombocytopenia (21.6%), a frequency higher than the frequency in the global population (5.7%). Grade ≥ 3 hemorrhage was reported in 1 patient (T-DM1 arm). In the KATHERINE study, T-DM1 demonstrated increased efficacy compared to trastuzumab in Chinese patients. Consistent with previous data in Asian patients, T-DM1 was associated with more grade ≥ 3 AEs, and AEs leading to discontinuation, which was driven by an increase in thrombocytopenia.

Trastuzumab is the only approved targeted therapy in patients with HER2-amplified metastatic gastric cancer (GC). Regrettably, in clinical practice, only a fraction of them achieves long-term benefit from trastuzumab-based upfront strategy. To advance precision oncology, we investigated the therapeutic efficacy of different HER2-targeted strategies, in HER2 “hyper”-amplified (≥ 8 copies) tumors. We undertook a prospective evaluation of HER2 targeting with monoclonal antibodies, tyrosine kinase inhibitors and antibody–drug conjugates, in a selected subgroup of HER2 “hyper”-amplified gastric patient-derived xenografts (PDXs), through the design of ad hoc preclinical trials. Despite the high level of HER2 amplification, trastuzumab elicited a partial response only in 2 out of 8 PDX models. The dual-HER2 blockade with trastuzumab plus either pertuzumab or lapatinib led to complete and durable responses in 5 (62.5%) out of 8 models, including one tumor bearing a concomitant HER2 mutation. In a resistant PDX harboring KRAS amplification, the novel antibody–drug conjugate trastuzumab deruxtecan (but not trastuzumab emtansine) overcame KRAS-mediated resistance. We also identified a HGF-mediated non-cell-autonomous mechanism of secondary resistance to anti-HER2 drugs, responsive to MET co-targeting. These preclinical randomized trials clearly indicate that in HER2-driven gastric tumors, a boosted HER2 therapeutic blockade is required for optimal efficacy, leading to complete and durable responses in most of the cases. Our results suggest that a selected subpopulation of HER2-“hyper”-amplified GC patients could strongly benefit from this strategy. Despite the negative results of clinical trials, the dual blockade should be reconsidered for patients with clearly HER2-addicted cancers.

Summary: HER2 amplification heterogeneity is associated with resistance to trastuzumab emtansine in the neoadjuvant setting, emphasizing the importance of assessing whether heterogeneous HER2-positive cancers require different treatment pathways. See related article by Metzger Filho et al., p. 2474.

Background T-DXd is a novel antibody-drug conjugate composed of an anti-HER2 antibody, cleavable tetrapeptide-based linker, and membrane-permeable topoisomerase I inhibitor payload. In a phase 2 study in patients (pts) with HER2+ (IHC 3+ or IHC 2+/ISH+), unresectable or metastatic breast cancer (MBC) previously treated with trastuzumab emtansine (T-DM1), the confirmed ORR (cORR) with T-DXd was 60.9% and median PFS (mPFS) was 16.4 mo (Modi NEJM 2020). In pts with HER2-low (IHC 2+/ISH−, IHC 1+) advanced BC, cORR was 37.0% and mPFS 11.1 mo in a phase 1 study (Modi J Clin Oncol 2020). Recently, T-DXd was approved for the treatment of adult pts with HER2+, unresectable or MBC who have received ≥ 2 prior anti-HER2-based regimens (US) or had prior chemotherapy and are refractory to or intolerant of standard treatments (Japan). In preclinical models, T-DXd combined with an anti-PD-1 antibody had greater efficacy than either agent alone (Iwata Mol Cancer Ther 2018). We conducted a phase 1b, open-label, multicenter, 2-part study of T-DXd in combination with nivolumab (Nivo) in pts with HER2-expressing (by centrally testing) MBC or advanced urothelial cancer (DS8201-A-U105; NCT03523572); interim results for the BC cohorts are presented. Methods Pts were aged ≥18 y and immune checkpoint inhibitor naive. Pts were enrolled in the United States and Europe. In part 1 (dose escalation), pts received T-DXd 3.2 or 5.4 mg/kg intravenously (IV) every 3 weeks (q3w) and Nivo 360 mg IV q3w to determine the recommended dose for expansion (RDE). In part 2, the RDE was given to 2 MBC cohorts: HER2+ (IHC 3+ or IHC 2+/ISH+) disease that progressed on prior T-DM1 or HER2 low (IHC 1+ or IHC 2+/ISH−) disease that progressed on prior standard treatments. The primary efficacy endpoint is cORR by independent central review (ICR) per RECIST version 1.1 in part 2. Additional endpoints include duration of response (DOR), disease control rate (DCR), PFS, OS, safety, and pharmacokinetics. Results 52 pts with MBC were enrolled. In part 1, 4 pts received T-DXd 3.2 mg/kg (HER2+, n=3; HER2 low, n=1), 3 pts received 5.4 mg/kg (all HER2+). In part 2, 45 pts received the RDE of T-DXd 5.4 mg/kg and Nivo 360 mg (HER2+, n=29; HER2 low, n=16 [13 HR+]); median follow-up time was 7.0 and 6.9 mo, respectively. All pts (n=48) who received RDE were female; median duration of follow-up was 6.9 mo. HER2+ pts had a median age of 55 y and median of 5 prior lines of metastatic/locally advanced therapy. At data cutoff (June 8, 2020), 56.3% of pts remained on treatment (median treatment duration: T-DXd, 6.5 mo; Nivo, 5.2 mo). HER2 low pts had a median age of 47 y, median of 4 prior lines, and 50.0% remained on treatment (median: T-DXd, 6.3 mo; Nivo, 4.9 mo). In pts treated at RDE, the cORR by ICR in the HER2+ cohort was 59.4% (19/32, 18 PR) and for the HER2 low cohort was 37.5% (6/16, all PR). The DCR was 90.6% and 75.0% in the HER2+ and HER2-low cohorts, respectively. Median DOR was not reached in either cohort; median PFS was 8.6 mo (95% CI, 5.4-NE) for the HER2+ cohort and 6.3 mo (95% CI, 2.3-NE) for the HER2 low cohort. Adverse events (AEs) grade ≥3 occurred in 43.8% (18.8% related to T-DXd, 18.8% to Nivo) of pts treated at RDE (n=48); anemia (16.7%) and transaminase increase (6.3%) were most common. Nausea (54.2%), fatigue (45.8%), and alopecia (41.7%) were the most common any-grade AEs. 5 pts (10.4%, all HER2+) had treatment-related interstitial lung disease (ILD) as adjudicated by an independent committee (grade 5, n=1; grade 2, n=4). No other deaths associated with a drug-related AE occurred. Conclusions In pts with HER2-expressing MBC, T-DXd plus Nivo demonstrated antitumor activity consistent with prior studies of T-DXd and had an acceptable safety profile in this interim analysis; whether adding IO therapy to T-DXd benefits pts requires longer follow-up and additional studies. Citation Format: Erika Hamilton, Charles L Shapiro, Daniel Petrylak, Valentina Boni, Miguel Martin, Gianluca Del Conte, Javier Cortes, Laila Agarwal, Hendrik-Tobias Arkenau, Antoinette R. Tan, Philip Debruyne, Anna Minchom, Annemie Rutten, Frances Valdes-Albini, Evan Y Yu, Bincy Augustine, Anthony D'Amelio, Jr., Daniel Barrios, Sara A. Hurvitz. Trastuzumab deruxtecan (T-DXd; DS-8201) with nivolumab in patients with HER2-expressing, advanced breast cancer: A 2-part, phase 1b, multicenter, open-label study [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD3-07.

Background Tucatinib (TUC) is a highly selective oral tyrosine kinase inhibitor of HER2 with minimal inhibition of EGFR. It was recently approved by the FDA for patients (pts) with HER2+ metastatic breast cancer (MBC), including pts with brain metastases (BM) whose cancers have progressed on at least 1 prior anti-HER2 regimen in the metastatic setting. In the HER2CLIMB (NCT02614794) pivotal trial, pts with HER2+ MBC previously treated with trastuzumab (T), pertuzumab, and trastuzumab emtansine (T-DM1) were randomized to receive TUC or placebo in combination with T and capecitabine (C). The addition of TUC resulted in clinically meaningful and statistically significant improvements in overall survival (OS), progression-free survival (PFS), and objective response rate (ORR) in HER2+ MBC pts. Primary methods and outcomes have been reported previously (Murthy, NEJM 2019). Here we present an exploratory analysis describing the outcomes in the HER2CLIMB trial based on hormone receptor (HR) status. Methods Pts were randomized 2:1 to receive TUC or placebo in combination with T and C. All pts had a baseline brain MRI and randomization was stratified by presence of BM, ECOG status, and geographic region. All pts with HER2+ MBC who were positive for either or both estrogen receptor and progesterone receptor (> 1%) were assigned to the HR “positive” subgroup. Pts not meeting the above criteria were assigned to the HR “negative” subgroup. For the exploratory HR+/HR- efficacy analysis presented here, PFS per RECIST 1.1 by blinded independent central review was evaluated in the first 480 pts enrolled. OS, PFS in pts with baseline BM, and confirmed ORR in pts with measurable disease were evaluated in the total study population. P values presented for PFS are nominal. Results Overall, 612 pts were enrolled to HER2CLIMB; 370 pts (60%) had HR+ and 242 (40%) had HR- tumors. Baseline demographics and disease characteristics in HR+/HR- subgroups were generally balanced between treatment arms. In the HR+ group, there was a 42% reduction in the risk of progression or death in the TUC arm (hazard ratio: 0.58; 95% CI: 0.42, 0.80; P=0.0008); median (95% CI) PFS was 7.6 mo (7.4, 9.5) in the TUC arm vs 5.6 mo (4.3, 7.4) in the control arm. In the HR- group, there was a 46% reduction in the risk of progression or death in the TUC arm (hazard ratio: 0.54; 95% CI: 0.34, 0.86; P=0.008); median (95% CI) PFS was 8.1 mo (7.0, 11.6) in the TUC arm vs 4.2 mo (3.1, 8.6) in the control arm. In the total population, median OS was 21.7 mo vs 18.2 mo in HR+ in the TUC arm vs control arm, respectively; median OS in HR- was 31.1 mo in the TUC arm vs 14.1 mo in the control arm. In pts with BM in the HR+ group (n=166 [45%]), there was a 52% reduction in the risk of progression or death (hazard ratio: 0.48; 95% CI: 0.31, 0.75; P=0.0008); median (95% CI) PFS was 7.5 mo (5.6, 9.5) in the TUC arm vs 5.1 mo (4.1, 5.7) in the control arm, and median OS was 18.1 mo vs 12.8 mo, respectively. In pts with BM in the HR- group (n=125 [52%]), there was a 50% reduction in the risk of progression or death (hazard ratio: 0.50; 95% CI: 0.27, 0.95; P=0.03); median (95% CI) PFS was 7.8 mo (6.1, 11.6) in the TUC arm vs 5.4 mo (2.9, 8.6) in the control arm, and median OS was 18.5 mo vs 11.5 mo, respectively. In the total population, ORR was numerically higher in the TUC arm vs the control arm regardless of HR status (HR+: 37.4% [95% CI: 30.8, 44.5] vs 27.1% [95% CI: 19.0, 36.6], respectively and HR-: 45.3% [95% CI: 36.7, 54.0] vs 15.6% [95% CI: 7.8, 26.9], respectively). Conclusions Among pts with HER2+ MBC previously treated with T, pertuzumab, and T-DM1, the addition of TUC to T and C showed clinically meaningful improvements of PFS, OS, and ORR independent of HR status. Furthermore, pts with HR+ and HR- MBC with BM derived similar benefit from the addition of TUC to T and C. Citation Format: Erika Hamilton, Mattea Reinisch, Sherene Loi, Alicia Okines, Paula R. Pohlmann, Eva Harder Brix, Hugues Bourgeois, Belinda Yeo, Cheryl Aylesworth, Melody Cobleigh, Anthony Goncalves, Rebecca Moroose, Katherine H.R. Tkaczuk, Michaela Tsai, Christine Simmons, Michael Andersson, Hatem Soliman, Michelina Cairo, Lisa A. Carey, David Cameron, Jorge Ramos, Wentao Feng, Mafalda Oliveira. Tucatinib vs placebo in combination with trastuzumab and capecitabine for patients with locally advanced unresectable or HER2-positive metastatic breast cancer (HER2CLIMB): Outcomes by hormone receptor status [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD3-08.

Background: HER2 activating mutations occur in 2-5% of metastatic breast cancer (MBC) patients, and three phase II or basket clinical trials have shown that the irreversible pan-HER tyrosine kinase inhibitor, neratinib, has good single agent efficacy for HER2 mutated MBC patients. Current trials are combining neratinib with other targeted therapies to increase response rate and progression free survival for these patients. Methods: We established patient derived xenografts (PDX) and organoids from two patients with HER2 mutated, non-amplified MBC and used them to test neratinib with the antibody drug conjugates (ADC’s), trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd), both in 3D culture and in vivo. Real time, in vivo uptake of these ADC’s was visualized with a near infrared fluorophore. Results: PDX lines WHIM51 and WHIM64 were established from ER+, HER2 non-amplified MBC patients that had HER2 activating mutations. WHIM51 has HER2 exon 20 insertion mutation at amino acid 776 (ERBB2 A775_G776insYVMA) and WHIM64 has a HER2 L869R missense mutation, both of which are located in the HER2 tyrosine kinase domain. Both of these HER2 mutations have been previously characterized and are known activating mutations. Organoids were established from both PDX’s and were grown in 3D culture. Drug combination testing of neratinib with T-DM1 in 3D culture showed strong synergy and the mechanism was explored. We demonstrate that neratinib and other irreversible HER2 inhibitors increase the endocytic uptake of T-DM1, but this effect does not occur with the reversible HER2 inhibitors, tucatinib and lapatinib. Real time, in vivo uptake of T-DM1 was measured by labeling the ADC with a near infrared fluorophore and we observed statistically significant increase in T-DM1 uptake with neratinib pre-treatment. Combining neratinib with T-DM1 increased apoptosis at day 3 post-treatment and enhanced tumor shrinkage. With the FDA approval of T-DXd at the end of 2019, we hypothesized that this same mechanism may apply to neratinib combined with T-DXd. We have tested both the combinations of neratinib + T-DXd and neratinib + T-DM1 in vivo in both HER2 mutant PDX’s and observed statistically significant tumor regression with the neratinib + ADC combinations as compared to either T-DXd or T-DM1 on its own. Conclusions: Neratinib increases the endocytosis of trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd), thereby increasing tumor cell kill and causing greater tumor regression in HER2 mutated MBC. These data provide preclinical justification for trials of neratinib plus HER2 ADCs including T-DXd or T-DM1 in HER2 mutant or HER2+ MBC. Further, this mechanism of neratinib stimulated HER2 endocytosis may also apply to HER2 low MBC. Citation Format: Ron Bose, Shunqiang Li, Tina M. Primeau, Maureen K. Highkin, Ashley R. Tipton, Nagalaxmi Vemalapally, Xuefeng Gao, Gail Sudlow, Irmina Diala, Yu Tao, Jingqin Luo, Ian Hagemann, Chieh-Yu Lin, Richard P. Bryce, Alshad S. Lalani, Samuel Achilefu, Cynthia X. Ma. Irreversible inhibition of HER2 activating mutations with neratinib enhances the pre-clinical efficacy of trastuzumab emtansine and trastuzumab deruxtecan [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS4-13.

Trastuzumab deruxtecan is a novel antibody–drug conjugate for the treatment of advanced solid tumors, including breast cancer, which overexpress or have amplification of the human epidermal growth factor receptor 2 (HER2). The novel structure of this exciting new agent means that it can deliver a highly potent cytotoxic agent to HER2-expressing tissues resulting in selective killing of cancer cells. In phase I and II trials, trastuzumab deruxtecan has shown impressive response rates in heavily pretreated populations, including patients who had received prior treatment with trastuzumab emtansine, another highly active antibody–drug conjugate. The most common side effects are gastrointestinal and hematological. Importantly, a high rate of interstitial lung disease was seen in early trials, but this appears manageable in most patients with corticosteroids. In light of its efficacy, this promising new drug may change the treatment paradigm of HER2-positive breast cancer.

Background Trastuzumab emtansine (T-DM1) treatment for human epidermal growth factor receptor-2 (HER2)-positive metastatic breast cancer after taxane with trastuzumab and pertuzumab is standard therapy. However, treatment strategies beyond T-DM1 are still in development with insufficient evidence of their effectiveness. Here, we aimed to evaluate real-world treatment choice and efficacy of treatments after T-DM1 for HER2-positive metastatic breast cancer. Methods In this multi-centre retrospective cohort study involving 17 hospitals, 325 female HER2-positive metastatic breast cancer patients whose post-T-DM1 treatment began between April 15, 2014 and December 31, 2018 were enrolled. The primary end point was the objective response rate (ORR) of post-T-DM1 treatments. Secondary end points included disease control rate (DCR), progression-free survival (PFS), time to treatment failure (TTF), and overall survival (OS). Results The median number of prior treatments of post-T-DM1 treatment was four. The types of post-T-DM1 treatments included (1) chemotherapy in combination with trastuzumab and pertuzumab (n = 102; 31.4%), (2) chemotherapy concomitant with trastuzumab (n = 78; 24.0%), (3), lapatinib with capecitabine (n = 63; 19.4%), and (4) others (n = 82; 25.2%). ORR was 22.8% [95% confidence interval (CI): 18.1–28.0], DCR = 66.6% (95% CI 60.8–72.0), median PFS = 6.1 months (95% CI 5.3–6.7), median TTF = 5.1 months (95% CI 4.4–5.6), and median OS = 23.7 months (95% CI 20.7–27.4). Conclusion The benefits of treatments after T-DM1 are limited. Further investigation of new treatment strategies beyond T-DM1 is awaited for HER2-positive metastatic breast cancer patients.

Trastuzumab-emtansine (T-DM1) is an antibody-drug conjugate (ADC) that efficiently delivers a highly potent microtubule inhibitor to HER2 overexpressing cells. Herein, we utilize HER2 transformed human mammary epithelial cells (HME2) to demonstrate in vitro and in vivo response and recurrence upon T-DM1 treatment. Continuous in vitro dosing of HME2 cells with T-DM1 failed to produce a spontaneously resistant cell line. However, induction of epithelial–mesenchymal transition (EMT) via pretreatment with TGF-β1 was capable of promoting emergence of T-DM1-resistant (TDM1R) cells. Flow cytometric analyses indicated that induction of EMT decreased trastuzumab binding, prior to overt loss of HER2 expression in TDM1R cells. Kinome analyses of TDM1R cells indicated increased phosphorylation of ErbB1, ErbB4, and FGFR1. TDM1R cells failed to respond to the ErbB kinase inhibitors lapatinib and afatinib, but they acquired sensitivity to FIIN4, a covalent FGFR kinase inhibitor. In vivo, minimal residual disease (MRD) remained detectable via bioluminescent imaging following T-DM1-induced tumor regression. Upon cessation of the ADC, relapse occurred and secondary tumors were resistant to additional rounds of T-DM1. These recurrent tumors could be inhibited by FIIN4. Moreover, ectopic overexpression of FGFR1 was sufficient to enhance tumor growth, diminish trastuzumab binding, and promote recurrence following T-DM1-induced MRD. Finally, patient-derived xenografts from a HER2+ breast cancer patient who had progressed on trastuzumab failed to respond to T-DM1, but tumor growth was significantly inhibited by FIIN4. Overall, our studies strongly support therapeutic combination of TDM1 with FGFR-targeted agents in HER2+ breast cancer.

Antibody-drug conjugates (ADCs) combine the specific antibody and cytotoxic agent by a linker and represent a promising drug class with a wider therapeutic window than conventional chemotherapeutic agents by substantiating efficient and specific drug delivery to antigen-expressing tumor cells. However, there are rooms for improvement in terms of efficacy, safety, physicochemical property; therefore, the development of promising ADC drugs across multiple indications are eagerly awaited. In 2015, Daiichi Sankyo initiated the first-in-human study of HER2 ADC, trastuzumab deruxtecan (T-DXd, ENHERTU®) which possesses DNA topoisomerase I inhibitor, exatecan derivative and proprietary linker, in Japan. Based on the provocative results in phase 1 study, the global development program has been accelerated to show the high and durable efficacy in patients with HER2 positive breast cancer pretreated with trastuzumab emtansine. As a result, T-DXd was approved based on single arm phase 2 study in the US (Dec 2019) and Japan (March 2020) by leveraging the breakthrough designation and conditional early approval system, respectively, at the first time for the HER2 positive breast cancer. In addition, T-DXd was recently approved in gastric cancer through Sakigake designation in Japan based on a randomized phase 2 study. T-DXd is also being developed in the earlier lines or other indications where no anti-HER2 therapies were approved to date. Combination studies with other agents, such as immune checkpoint inhibitors are underway. In the near future, we hope that more patients worldwide can enjoy the therapeutic benefits of T-DXd through our continuous efforts to expand its indications.

Highlights • Few studies have examined management of breast cancer patients on hemodialysis. • Dosage for anticancer drugs should be carefully adjusted based on adverse events. • Combined therapy improves survival and quality of life., Introduction Management of breast cancer patients undergoing hemodialysis (HD) is difficult because of a lack of evidence about drug selection, dose adjustment, and surgical procedures. We herein present a case of metastatic breast cancer in a patient undergoing HD. Presentation of case A 58-year-old Japanese woman with breast cancer undergoing HD underwent total mastectomy of the left breast and left axillary dissection. Histopathological examination revealed invasive ductal carcinoma, and the diagnosis was pT2N3cM0 Stage ⅢC. Immunostaining of the resected specimen indicated that the tumor was estrogen receptor-positive, progesterone receptor-negative, human epithelial growth factor receptor 2-positive, and the Ki-67 labeling index was 70%. A postoperative positron emission tomography/computed tomography (PET/CT) scan indicated fluorodeoxyglucose uptake in the supraclavicular nodes. She received adjuvant therapy of epirubicin and cyclophosphamide followed by docetaxel, trastuzumab (T-mab) and radiation therapy. However, she developed multiple liver metastases during adjuvant T-mab and hormone therapy. Therefore, her regimen was changed to trastuzumab emtansine (T-DM1) as first-line therapy, T-mab, pertuzumab (P-mab), and eribulin as second-line therapy, and T-mab, P-mab, and weekly paclitaxel as third-line therapy. Eventually, she was administered fourth-line treatment of T-mab, P-mab, and vinorelbine because of adverse events. She has survived more than 25 months after the initial detection of recurrence of breast cancer and maintained quality of life. Conclusion We report a case of breast cancer in a patient undergoing HD. It is very difficult to identify the appropriate drugs and dosages in patients undergoing HD to improve survival and quality of life.

No specific standard treatment is currently recommended for HER2-positive advanced breast cancer (BC) patients progressing to dual HER2 blockade and to trastuzumab emtansine (TDM-1). However, several novel anti-HER2 agents are emerging and rapidly revolutionizing this setting. Among these, the FC-engineered monoclonal antibody margetuximab has recently demonstrated to slightly improve progression-free survival (PFS) compared with trastuzumab, when combined with chemotherapy for pretreated HER2-positive advanced BC.The present review article recapitulates the clinical development of margetuximab, critically discussing its implications in the current landscape of BC treatment algorithms.The clinical role of Margetuximab can only be interpreted in view of the rapidly evolving treatment landscape for pretreated HER2-positive advanced BC. Indeed, the recently approved anti-HER2 agents tucatinib and trastuzumab deruxtecan currently represent appealing options for the post-TDM1 setting, while margetuximab may have a role after progression to the abovementioned agents, in case of a future approval. Regardless of its clinical uptake, it should be noted that the development of margetuximab has relevantly improved our biological understanding of HER2-positive BC, highlighting the implication of patient's genotype in determining treatment outcomes, as well as the relevance of antibody-dependent cellular cytotoxicity (ADCC) in the context of HER2-blockade.

Patients with brain metastases of HER2-positive breast cancer (BC) is a special group of patients who are difficult to treat and have a short life expectancy. The possibilities of whole brain radiotherapy, stereotactic radiosurgery and surgery in such patients are rather limited. Trastuzumab emtansine (T-DM1) showed potential activity in this subset of patients. T-DM1 is an antibody-chemical conjugate (ADC) that delivers directly to HER2-positive cancer cells, thereby limiting damage to healthy tissue. At this point, the efficacy of trastuzumab emtansine has been demonstrated in several randomized trials as a second and subsequent lines of therapy for advanced breast cancer with a favorable toxicity profile of the drug. This article describes a clinical case of a patient with luminal B HER-2 positive breast cancer who, underwent stereotactic radiosurgery and was treated with trastuzumab emtansine as a the second line of treatment for disease progression with metastatic brain lesions after trastuzumab/pertuzumab-containing therapy. Partial regression of metastases with long-term duration of the effect was achieved treatment with trastuzumab emtazine has been being continued for 24 months. Tolerability of therapy was good: thrombocytopenia 2 degree was the main among side effects. The effect has been persisted for 2 years and the patient continues the treatment. Discussion of the results of real clinical practice with well-known studies was carried out.

INTRODUCTION: Treatment of human epithelial growth factor receptor 2 (HER2)-positive breast cancer has rapidly evolved over the past decades with the addition of trastuzumab, lapatinib, pertuzumab, and trastuzumab emtansine (T-DM1). These treatments have dramatically impacted the survival of HER2-positive metastatic breast cancer (mBC) patients. Nonetheless, these agents are associated with high price tags, begging the question, ‘Are treatments for HER2-positive metastatic breast cancer and associated metastases cost-effective’? AREAS COVERED: We examine evidence on the cost-effectiveness of treatments for HER2-positive metastatic breast cancer and associated metastases through a review of systematic reviews on the topic. Additionally, we discuss the implications of our findings and provide recommendations for future directions in the assessment of the cost-effectiveness of targeted directed agents for HER2-positive mBC. EXPERT OPINION: Heterogeneous evidence from cost-effectiveness studies on the use of targeted directed agents for HER2-positive mBC across the world caution against cross-country comparisons of the value of such treatments. It also militates in favor of the production and use of cost-effectiveness analyses for local rather than global decision-making, thus ensuring that economic evaluations reflect the needs of local decision-makers and populations for which they are devised.

Trastuzumab emtansine (T-DM1), given postoperatively for 14 cycles to patients with human epidermal growth factor receptor 2-positive (HER2-positive) early breast cancer (EBC) who failed to achieve a pathological complete response after standard chemotherapy and HER2 blockade, represents probably the greatest progress in the management of this aggressive form of breast cancer since the adjuvant trastuzumab pivotal trials. This article addresses the rationale behind the conception of the KATHERINE trial, T-DM1’s structure and pharmacokinetics data, clinical efficacy data of the KATHERINE trial and of other EBC trials with T-DM1, safety aspects, implications of the KATHERINE trial results to clinical practice and future perspectives in the management of HER2-positive EBC.

At the 2019 ASCO Annual Meeting, the optimal approach to axillary surgery for women who received neoadjuvant chemotherapy (NACT) was discussed. If residual axillary disease is detected, patients with triple-negative tumors and human epidermal growth factor receptor 2 (HER2) overexpression can be selected for additional adjuvant treatment with capecitabine or trastuzumab emtansine (T-DM1), respectively.1,2 Failure to identify patients with residual disease can negatively affect their clinical outcome. Techniques proposed to optimize patient selection include placing clips on metastatic lymph nodes before NACT or performing axillary dissection even after a clinical complete response (CR). Does this really make sense? What role does axillary surgery play in patients for whom NACT is indicated?

Breast cancer is the leading cause of cancer-related death in female worldwide. Human epidermal growth factor receptor 2 (HER2) amplification is observed in approximately 20% of breast cancer cases and is associated with poor clinical outcomes. Dual HER2 blockade without chemotherapy represents an attractive therapeutic approach, and it remains unresolved if anti-HER2 therapeutic antibodies are sufficient to replace chemotherapy regimens. In this review, we discuss the approved therapeutic monoclonal antibodies (pertuzumab and trastuzumab) and antibody-drug conjugate (trastuzumab emtansine or T-DM1) for the treatment of HER2-positive breast cancer patients. In summary, phase II and III clinical trials have demonstrated that dual HER2 blockade (pertuzumab and trastuzumab) plus chemotherapy regimens confer better efficacy compared with dual HER2 blockade alone, or anti-HER2 antibody monotherapy, in HER2-positive breast cancer patients. Dual HER2 blockade (pertuzumab and trastuzumab) combined with chemotherapies (5-fluorouracil, epirubicin, cyclophosphamide and docetaxel) yield superior response. Moreover, dual HER2 blockade (T-DM1 and pertuzumab) in combination with docetaxel represents a promising treatment regimen containing T-DM1. Ongoing clinical trials are assessing the optimal chemotherapy of choice with anti-HER2 antibodies combinations. In conclusion, improved outcomes are attributable to selection for the optimal chemotherapy regimen in combination with anti-HER2 antibodies instead of replacing chemotherapy altogether with the current line of anti-HER2 therapeutic antibodies.

The human epidermal growth factor receptor 2 (HER2), is amplified and/or overexpressed in approximately 15%-20% of breast cancers. Targeting of the HER2 receptor with the humanized monoclonal antibody trastuzumab in combination with chemotherapy has become the backbone of treatment for both early stage and metastatic breast cancer for the last 2 decades. Relapsed or de novo metastatic HER2-positive breast cancer essentially remains an incurable disease. Nonetheless, with advances in therapeutics, survival rates in this group continue to increase with median survival now in excess of 57 months. First line systemic therapy for HER2-positive metastatic breast cancer using taxane chemotherapy combined with trastuzumab and pertuzumab, and second line therapy with trastuzumab emtansine, are well established. Recent studies of small molecule oral tyrosine kinase inhibitors such as tucatinib and neratinib, and antibody drug conjugates such as trastuzumab deruxtecan further improve outcomes. Major treatment challenges remain in the areas of brain metastases and development of drug resistance. This review details an up to date analysis of current and emerging treatments of metastatic HER2-positive breast cancer.

Trastuzumab emtansine (Kadcyla®), an antibody–drug conjugate of trastuzumab (Herceptin®) connected by a thioether linker to the microtubule inhibitor DM1 (a cytotoxic derivative of maytansine), provides direct intracellular delivery of the potent cytotoxin DM1 to HER2-overexpressing cells, while retaining trastuzumab activity. Its approval in metastatic/advanced breast cancer (BC) has been extended to include single-agent adjuvant treatment of HER2-positive early BC in patients with residual invasive disease in the breast and/or lymph nodes after neoadjuvant taxane-based and HER2-targeted treatment. In the pivotal KATHERINE trial in this population, significantly more trastuzumab emtansine than trastuzumab recipients were estimated to be free of invasive disease recurrence at 3 years, with a 50% reduction in the risk of invasive disease recurrence or death. The tolerability of trastuzumab emtansine in early BC was consistent with its known safety profile; as expected, adverse events were more common with trastuzumab emtansine than with trastuzumab. Recently updated international and national treatment guidelines recommend trastuzumab emtansine as a preferred option in this high-risk BC population.

Tumor human epidermal growth factor receptor 2 (HER2) status is defined by either protein expression using immunohistochemistry (IHC) or gene amplification using fluorescence in situ hybridization (FISH). Approximately 20% of HER2-positive breast cancer is HER2 IHC 2+/FISH-positive. Unlike trastuzumab, it has not been studied whether the response to trastuzumab emtansine (T-DM1) differs according to HER2-positive status. We retrospectively identified and reviewed medical records of all patients with HER2-positive advanced breast cancer (ABC) who received T-DM1 in our hospital from October 2013 to December 2016. We compared the objective response rate (ORR) and progression-free survival (PFS) between patients in the HER2 IHC 3+ group and those in the HER2 IHC 2+/FISH-positive group. A total of 39 patients (IHC 3+: n = 32; IHC 2+/FISH-positive: n = 7) were analyzed. Nineteen (48.7%), 13 (33.3%), and 29 (74.4%) patients had received at least one prior chemotherapy, more than three lines of chemotherapy, and prior pertuzumab for ABC, respectively. ORR was significantly higher in the IHC 3+ group than in the IHC 2+/FISH-positive group (53.3% vs. 0%, P = 0.024). Median PFS was 7.9 months in the IHC 3+ group versus 3.9 months in the IHC 2+/FISH-positive group (hazard ratio 0.68; 95% confidence interval 0.28-1.69, P = 0.408). Among the HER2-positive ABC patients treated with T-DM1, ORR was significantly worse in HER2 IHC 2+/FISH-positive than in HER2 IHC 3+ patients. Median PFS tended to be shorter in patients with HER2 IHC 2+/FISH-positive.

Human epidermal growth factor receptor 2 (HER2) is overexpressed in approximately 20% of all breast cancers. Before the development of HER2-directed monoclonal antibodies, HER2-positive breast cancer was associated with a rather poor prognosis. With the advent of monoclonal HER2-targeting antibodies (trastuzumab and pertuzumab) and antibody-drug conjugates (trastuzumab emtansine [T-DM1] and trastuzumab deruxtecan), clinical outcomes for HER2-positive breast cancer have dramatically changed, and a greater proportion of patients in the nonmetastatic setting are cured. However, in the metastatic setting, resistance to anti-HER2 treatments still remains a major therapeutic challenge, underscoring the importance of developing novel HER2-directed therapies. Over the last year, there has been a dramatic shift in the current treatment paradigms for HER2-positive metastatic breast cancer, with recent U.S. Food and Drug Administration approvals of trastuzumab deruxtecan (DS-8201), neratinib, and tucatinib in combination with trastuzumab and capecitabine. The authors summarize recent phase 3 data with novel HER2-targeted therapies as well as phase 1 and 2 data with other novel HER2-targeting agents.

Purpose Following neoadjuvant chemotherapy for breast cancer, postoperative systemic therapy, also called post-neoadjuvant treatment, has been established in defined risk settings. We reviewed the evidence for sequencing of postoperative radiation and chemotherapy, with a focus on a capecitabine and trastuzumab emtansine (T-DM1)-based regimen. Methods A systematic literature search using the PubMed/MEDLINE/Web of Science database was performed. We included prospective and retrospective reports published since 2015 and provided clinical data on toxicity and effectiveness. Results Six studies were included, five of which investigated capecitabine-containing regimens. Of these, four were prospective investigations and one a retrospective matched comparative analysis. One randomized prospective trial was found for T‑DM1 and radiotherapy. In the majority of these reports, radiation-associated toxicities were not specifically addressed. Conclusion Regarding oncologic outcome, the influence of sequencing radiation therapy with maintenance capecitabine chemotherapy in the post-neoadjuvant setting is unclear. Synchronous administration of capecitabine is feasible, but reports on possible excess toxicities are partially conflicting. Dose reduction of capecitabine should be considered, especially if normofractionated radiotherapy is used. In terms of tolerance, hypofractionated schedules seem to be superior in terms of toxicity in concurrent settings. T‑DM1 can safely be administered concurrently with radiotherapy.

Purpose of review Antibody-drug conjugates (ADCs) represent a new class of drugs that combine a surface receptor-targeting antibody linked to a cytotoxic molecule. This review summarizes the current literature demonstrating their tremendous promise as therapeutic agents in the treatment of aggressive gynecologic malignancies. Recent findings Several antigens have proven to be differentially overexpressed in a variety of gynecologic tumors when compared with normal surrounding tissue and serve as novel targets for ADC therapy. In the last few years HER2/neu, folic acid-alpha (FRα) and Trop-2 overexpression have been exploited as excellent targets by novel ADCs such as Trastuzumab emtansine (T-DM1), SYD985, IMGN853 (Mirvetuximab soravtansine) and Sacituzumab govitecan (SG, IMMU-132) in multiple tumors including ovarian, endometrial and cervical cancers. Although the selectivity of ADCs with noncleavable linkers (i.e. T-DM1) has shown negligible effect on surrounding antigen negative cells, those ADCs with cleavable linkers (i.e. SYD985, IMGN853 and SG) may kill both antigen-positive target cells and surrounding antigen-negative cells via the bystander effect. Summary Preclinical data strongly supports these ADCs and ongoing clinical trials will shed further light into the potential of making these drugs part of current standard practice and providing our patients with a higher level of personalized cancer care.

Purpose Anti-human epidermal growth factor receptor 2 (HER2) therapies are associated with interstitial lung disease (ILD), also referred to as pneumonitis. In this literature review, we describe the incidence of ILD among patients with HER2-positive metastatic breast cancer (MBC) receiving anti-HER2 therapies, and we describe existing recommendations for monitoring and managing drug-induced ILD among these patients. Methods We searched PubMed and Embase to identify clinical trials and postmarket observational studies that investigated anti-HER2 therapies for HER2-positive MBC, reported on ILD, and were published during January 1, 2009 to July 15, 2019. Articles were screened by two researchers; data were extracted from the full-text articles. Results The 18 articles selected for this review assessed 9,886 patients who received trastuzumab (8 articles), lapatinib (4 articles), trastuzumab emtansine (3 articles), trastuzumab deruxtecan (2 articles), or trastuzumab duocarmazine (1 article). The overall incidence of all-grade ILD was 2.4% (n = 234), with 66.7% (n = 156) occurring as grade 1–2 events, 0.5% grade 3–4 (n = 54; incidence), and 0.2% grade 5 (n = 16; incidence). The highest ILD incidence (21.4%) was among patients receiving trastuzumab combined with everolimus and paclitaxel. Ten studies indicated that ILD events were managed via dose interruption, dose reduction, or treatment discontinuation; two studies included detailed guidelines on managing drug-induced ILD. Conclusions ILD is a well-described adverse drug reaction associated with several anti-HER2 drugs. Published ILD management guidelines are available for few anti-HER2 treatment regimens; however, guidance for monitoring for anti-HER2 drug-induced ILD is lacking.

Despite relevant medical advancements, metastatic breast cancer remains an uncurable disease. HER2 signaling conditions tumor behavior and treatment strategies of HER2 expressing breast cancer. Cancer treatment guidelines uniformly identify dual blockade with pertuzumab and trastuzumab plus a taxane as best first line and trastuzumab emtansine as preferred second line choice. However, there is no prospectively designed available study focusing on the sequence and outcomes of patients treated with T-DM1 following the triplet. In the following report, data concerning a wide series of patients treated in a real-life setting are presented. Results obtained in terms of response and median progression free survival suggests a significant role for T-DM1 in disease control of metastatic HER2 expressing breast cancer.

What is known and objective Trastuzumab‐emtansine is an antibody‐drug conjugate developed to decrease off‐target toxicity. According to the product label, reactions secondary to extravasation are mild or moderate. Case summary We report on a 51‐year‐old woman who developed epidermal necrosis after extravasation of trastuzumab‐emtansine, which required surgical intervention. Six weeks later, the lesions were healed with residual hyperpigmentation. What is new and conclusion We describe the course of a case of severe toxicity following trastuzumab‐emtansine extravasation. We provide treatment recommendations and recommend amending the information on the product label on extravasation., This report describes the course of severe skin toxicity following trastuzumab‐emtansine extravastion and provides treatment recommendations.

We have demonstrated that microtubule destabilizing agents (MDAs) can sensitize tumors to oncolytic vesicular stomatitis virus (VSVΔ51) in various preclinical models of cancer. The clinically approved T-DM1 (Kadcyla®) is an antibody-drug conjugate consisting of HER2-targeting trastuzumab linked to the potent MDA and maytansine derivative DM1. We reveal that combining T-DM1 with VSVΔ51 leads to increased viral spread and tumor killing in trastuzumab-binding, VSVΔ51-resistant cancer cells. In vivo, co-treatment of VSVΔ51 and T-DM1 increased overall survival in HER2-overexpressing, but trastuzumab-refractory, JIMT1 human breast cancer xenografts compared to monotherapies. Furthermore, viral spread in cultured HER2+ human ovarian cancer patient-derived ascites samples was enhanced by the combination of VSVΔ51 and T-DM1. Our data using the clinically approved Kadcyla® in combination with VSVΔ51 demonstrates proof of concept that targeted delivery of a viral-sensitizing molecule using an antibody-drug conjugate can enhance oncolytic virus activity and provides rationale for translation of this approach., Arulanandam et al. demonstrate that HER2 positive cancer cells are sensitized to oncolytic rhabdovirus by an antibody-drug conjugate consisting of HER2- targeting trastuzumab linked to the microtubule destabiliser DM1. This study suggests the potential of such combination therapy in the treatment of HER2-positive cancers.