Trastuzumab emtansine versus treatment of physician's choice in patients with previously treated HER2-positive metastatic breast cancer (TH3RESA): final overall survival results from a randomised open-label phase 3 trial

Factors Associated With Short- and Long-Term Survival in Metastatic HER2-Positive Breast Cancer

BACKGROUND

We sought to evaluate prognostic factors in human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) and their relationship with short- and long-term overall survival (OS).

METHODS

Using the Surveillance, Epidemiology, and End Results (SEER) database, we evaluated patients with de novo HER2-positive MBC diagnosed from 2010 to 2018. Univariate analyses were performed to determine effect of each variable on OS. Significant variables were included in a multivariate Cox model for OS. Univariate and multivariate logistic regression were used to evaluate the association of each variable with short- (<2 years) and long- (≥5 years) term OS.

RESULTS

Overall, 5576 patients were included. Median follow up was 48 months (interquartile range 25-73 months), and median OS was 41 months. The proportion alive at 2, 5, and 8 years was 63.3% (95% confidence interval [CI] 62.0%-64.7%), 37.8% (95% CI, 36.2%-39.4%), and 26.8% (95% CI, 24.8%-28.9%), respectively. Factors associated with short-term OS were older age; Black race; nonductal nonlobular; brain, liver, or lung metastases; estrogen/progesterone receptor (ER/PR)-negative disease, and lower income (all P < .04). Number of metastatic organ sites was not significant. Factors associated with long-term OS were younger age, White race, fewer metastatic organ sites, ER/PR-positive disease, and higher income (all P < .02). Specific organ sites were not significant.

CONCLUSIONS

In this cohort with de novo HER2-positive MBC, OS improved significantly over the study period. We identified patient-specific and tumor-specific factors that were associated with short- and long-term survival in HER2-positive MBC.

Adverse events and impact on quality of life of antibody-drug conjugates in the treatment of metastatic breast cancer: A systematic review and meta-analysis

BACKGROUND

Antibody-drug conjugates are novel effective therapies for metastatic breast cancer. Nevertheless, their toxicity profile can significantly affect patients' quality of life over time.

METHODS

This is a systematic review and meta-analysis of randomized controlled trials of antibody-drug conjugates currently approved for the treatment of metastatic breast cancer [trastuzumab-emtansine (T-DM1), trastuzumab deruxtecan (T-DXd) and sacituzumab-govitecan (SG)] versus standard therapy to evaluate the risk of adverse events, discontinuation rate due to toxicity, impact on quality of life according to EORTC QLQ-C30 scale and subdomains. Relative risks (RR) and hazard ratios (HR) with 95% CIs were calculated using random effects models.

RESULTS

Nine trials with a total of 5753 patients were included. The most common adverse events of any grade for T-DM1 included thrombocytopenia (RR 7.14, 95% CI 4.13-12.36) and increased alanine-transaminase (ALT) (RR 2.04, 95% CI 1.43-2.91), for T-DXd were nausea (RR 2.39, 95% CI 1.90-3.00) and anemia (RR 1.55, 95% CI 1.27-1.90), while for SG were neutropenia (RR 1.30, 95% CI 1.14-1.49), diarrhea (RR 3.62, 95% CI 2.97-4.42) and nausea (RR1.90, 95% CI 1.65-2.19). Severe adverse events such as interstitial lung disease and left ventricular dysfunction were peculiar of T-DXd. Antibody-drug conjugates significantly delayed clinical deterioration of global health status by EORTC QLQ-C30 (HR .71, 95% CI .59-.86), physical, emotional and social functioning, pain and fatigue symptoms.

CONCLUSIONS

This meta-analysis offers consolidated data on adverse events associated with antibody-drug conjugates and their effects on patients' quality of life, emphasizing differences based on the specific agent. These findings underscore the critical need for effective strategies to prevent, diagnose and manage these toxicities.

Real-world data on trastuzumab emtansine (TDM1) efficacy and safety: Results of a single-centre retrospective study of HER2-positive metastatic breast cancer patients

HER2-positive metastatic breast cancer (MBC) represents a challenging subtype of breast cancer, characterized by aggressive disease and poor clinical outcomes. Trastuzumab emtansine (TDM1), an antibody-drug conjugate combining trastuzumab and emtansine, has demonstrated efficacy in clinical trials as a second-line treatment for patients progressing after prior therapies. This study aims to provide real-world evidence on the efficacy and safety of TDM1 in HER2-positive MBC patients. A retrospective analysis was conducted on 70 HER2-positive MBC patients treated with TDM1 at our centre between January 2020 and December 2022. Clinical characteristics, progression-free survival (PFS), overall survival (OS), response rates, and toxicity were evaluated using hospital records. PFS and OS were calculated using Kaplan-Meier methods, and survival curves were compared with log-rank tests. The median age of patients was 47 years, with a majority presenting with advanced disease and prior treatment lines. The median PFS was 6.1 months (95% CI, 4.5-7.6), and the median OS was 14.4 months (95% CI, 10.2-18.0). The objective response rate was 75.7%, with 12.8% achieving a complete response and 62.8% a partial response. PFS was significantly longer in hormone receptor-positive patients compared to hormone receptor-negative patients (8.1 vs. 4.1 months, p = 0.035). Toxicity was manageable, with grade 3-4 adverse events including elevated transaminases (8.5%), thrombocytopenia (5.7%), and anemia (4.2%). The efficacy of TDM1 in this real-world cohort aligns with clinical trial data, though PFS and OS were somewhat lower compared to trials, likely due to the inclusion of patients with more extensive disease and prior treatments. Notably, TDM1 demonstrated activity against CNS metastases and a manageable safety profile, with higher incidence of hepatic and hematologic toxicities. Our study supports the use of TDM1 as a viable option for treating HER2-positive MBC in routine clinical practice, confirming its effectiveness and safety profile observed in clinical trials.

Trastuzumab deruxtecan versus trastuzumab emtansine for human epidermal growth factor receptor 2 positive metastatic breast cancer: cost-effectiveness analysis from Iranian experience

BACKGROUND

This study aims to evaluate the cost-effectiveness of Trastuzumab deruxtecan (T-DXd), compared to trastuzumab emtansine (T-DM1) as second-line treatments for human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) patients in Iran.

METHODS

A partitioned survival model was developed based on time-to-event data from the DESTINY-Breast 03 trial to evaluate the cost-effectiveness of T-DXd versus T-DM1 from a societal perspective and over a lifetime horizon. Costs and utility inputs were derived from published literature and official Iranian sources. Key outcomes included total costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICER). The willingness-to-pay (WTP) threshold of $2413/QALY was applied. One-way sensitivity analyses and probabilistic sensitivity analyses (PSA) were conducted to assess uncertainty.

RESULTS

In the base-case analysis, T-DXd yielded 3.59 QALYs for $261,315, while T-DM1 yielded 1.89 QALYs at $258,039, resulting in an ICER of $1,927 per QALY. This value is below Iran's WTP threshold of $2413/QALY. One-way sensitivity analysis identified the unit price of T-DXd as the most influential parameter. PSA results indicated that T-DXd has a 52% probability of being cost-effective.

CONCLUSION

T-DXd represents a cost-effective alternative to T-DM1 as a second-line treatment for HER2-positive MBC in Iran. Its clinical advantages, combined with an ICER below the local WTP threshold, support its adoption in this patient population.

Risk of Ophthalmotoxicity Associated with Antibody-Drug Conjugates: A Systematic Review and Meta-analysis

BACKGROUND

Antibody-drug conjugates provide significant advantages in cancer therapy, but their associated ophthalmotoxicity remains insufficiently explored.

OBJECTIVE

Our objective was to determine the prevalence and risk of ophthalmotoxicity in patients receiving antibody-drug conjugates.

METHODS

We conducted a systematic search in MEDLINE, Embase, Web of Science, Cochrane, and ClinicalTrials.gov for phase II or III randomized clinical trials reporting ocular adverse events linked to antibody-drug conjugates up to 5 March, 2025. The Cochrane Bias Risk Assessment Tool was used to assess the risk of bias. The primary outcome was the risk of all-grade ocular adverse events induced by antibody-drug conjugates, measured by the risk ratio (RR) with 95% confidence intervals (CIs).

RESULTS

Thirty-one trials consisting of 18,490 patients were ultimately included. The pooled incidence of all-grade ocular adverse events following antibody-drug conjugate therapy was 10.45% (95% CI 4.51-18.42). Antibody-drug conjugates were linked to a potentially increased risk of ophthalmotoxicity (RR = 1.76, 95% CI 1.25-2.48), particularly with monomethyl auristatin E (RR = 2.73, 95% CI 1.42-5.28) and monomethyl auristatin F (RR = 3.01, 95% CI 2.58-3.52) payloads. Dry eye was the most common ocular manifestation (15.49%, 95% CI 7.66-25.38).

CONCLUSIONS

Antibody-drug conjugate therapy has been associated with an elevated risk of ophthalmotoxicity. Further research is needed to explore the influence of antibody-drug conjugate components, disease characteristics, and treatment regimens on ophthalmotoxicity risk.

CLINICAL TRIAL REGISTRATION

PROSPERO register name and registration number: Antibody-drug conjugates-related to ocular toxicity: a network meta-analysis and real-world pharmacovigilance study of the FAERS database (CRD42023458065).

HER2-Positive Breast Cancer-Current Treatment Management and New Therapeutic Methods for Brain Metastasis

Background: Breast cancer can be classified based on the immunohistochemistry (IHC) phenotypes, defined by the presence or absence of the main IHC markers. IHC phenotyping is important as it determines the prognosis and guides treatment. For example, human epidermal growth factor receptor 2 (HER2) overexpression, which triggers cell growth and division, is observed in HER2-positive breast cancer. Methods: The standard treatment is based on trastuzumab plus pertuzumab in combination with taxane chemotherapy. The possibility of developing metastases depends on those phenotypes. Approximately 25-50% of patients with HER2-positive breast cancer experience brain metastases. This aspect is especially important, as 20% of those patients die as a result. Results: Through the years, many advanced therapies have been introduced to treat brain metastases, including whole brain radiotherapy, stereotactic radiosurgery, and a tyrosine kinase inhibitor (TKI), neratinib. Nonetheless, this still remains a therapeutic challenge. Conclusions: In this review, we focus on the treatment and efficiency of therapies targeting HER2-positive breast cancer, mainly concentrating on the current and newly developed treatment options for brain metastases, such as trastuzumab deruxtecan and tucatinib.

Antibody-drug conjugates in elderly patients with breast cancer

Breast cancer remains a leading cause of cancer-related mortality worldwide, with elderly patients (aged >65 years) comprising a substantial portion of those affected. The treatment of breast cancer in this population is often complicated by frailty, comorbidities and polypharmacy. This review explores the application of antibody-drug conjugates (ADCs), such as trastuzumab emtansine (T-DM1), trastuzumab deruxtecan (T-DXd) and sacituzumab govitecan (SG), in treating breast cancer among elderly populations. The underrepresentation of older patients in clinical trials complicates efficacy and safety assessments in this group. Current evidence indicates that ADCs are both effective and tolerable in elderly patients, demonstrating improved progression-free survival (PFS) and overall survival (OS) alongside a manageable safety profile. Data from several trials like the EMILIA, TH3RESA and DestinyBreast studies demonstrate that T-DM1 and T-DXd maintained benefit in PFS and OS for HER2-positive breast cancer in older patients, despite a slight increase in adverse events. The ASCENT and TROPiCS-02 trials further confirm that SG provides significant improvements in PFS and OS in elderly patients at the cost of an increase in some toxicity. Emerging ADCs, including datopotamab deruxtecan and ARX-788, show promise but lack extensive geriatric-specific data. While the ADCs offer encouraging results in terms of efficacy and safety, with appropriate dose adjustments, further research is needed to optimize their use in elderly patients with breast cancer.

CRISPR screens with trastuzumab emtansine in HER2-positive breast cancer cell lines reveal new insights into drug resistance

BACKGROUND

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate that is an effective therapy for HER2-positive breast cancer; however, its efficacy is limited by drug resistance. While multiple mechanisms of resistance have been proposed, these are not yet well understood. Greater understanding of T-DM1 sensitivity and resistance could provide new combination strategies to overcome resistance or predictive biomarkers to guide therapy.

METHODS

We have conducted CRISPR/Cas9 functional genomics modifier screens in HER2-positive breast cancer cell lines to allow for unbiased discovery of T-DM1 sensitivity and resistance genes. Whole-genome knockout screens were carried out in MDA-MB-361 and MDA-MB-453 cells treated with T-DM1 and its payload cytotoxin DM1. Hits were validated in secondary T-DM1 screens using a focused single-guide RNA (sgRNA) library and subsequently by individual gene knockout.

RESULTS

The whole-genome CRISPR screens with T-DM1 and DM1 identified 599 genes as potential modifiers of T-DM1 sensitivity and resistance. Of these, 17 genes were significantly enriched and 3 genes depleted at P < 0.001 in either or both MDA-MB-361 and MDA-MB-453 libraries in the secondary screens. Among the top hits, were known T-DM1 sensitivity genes ERBB2 and SLC46A3, in addition to negative regulators of mTOR complex 1: TSC1 and TSC2. MDA-MB-453 clones with knockout of TSC1 or partial knockout of TSC2 were more resistant to T-DM1 than wild type cells in competition growth assays and to T-DM1 and other HER2 targeting therapies (T-DXd, lapatinib and neratinib) in growth inhibition assays, and had increased internalisation of T-DM1 at 6 h. T-DM1 and the mTOR inhibitor everolimus demonstrated synergistic activity at inhibiting cell proliferation at multiple T-DM1 concentrations across four HER2-positive breast cancer cell lines.

CONCLUSIONS

Our CRISPR screening approach with T-DM1 in HER2-positive breast cancer cell lines identified genes not previously implicated in T-DM1 sensitivity or resistance, including TSC1 and TSC2. These genes may inform new strategies to enhance T-DM1 therapy in the clinic.

Toxicities and management strategies of emerging antibody-drug conjugates in breast cancer

Antibody-drug conjugates (ADCs) offer a promising therapeutic approach for various cancers, enhancing the therapeutic window while mitigating systemic adverse effects on healthy tissues. ADCs have achieved remarkable clinical success, particularly in treating breast cancer, becoming a standard therapy across all subtypes, including hormone receptor-positive, human epidermal growth factor receptor 2-positive, and triple-negative breast cancer. Although designed to selectively target antigens via monoclonal antibodies, ADCs can exhibit toxicity in normal tissues, often due to off-target effects of their cytotoxic payloads. Understanding and managing these toxicities according to established guidelines are crucial for enhancing ADC clinical efficacy, minimizing adverse events, and ultimately improving patient outcomes. This review comprehensively examines the toxicities of ADCs employed in breast cancer treatment and explores their management strategies. Furthermore, we investigate novel ADCs beyond trastuzumab deruxtecan and sacituzumab govitecan, evaluating their potential efficacy and corresponding safety profiles.

Antibody-drug conjugates in breast cancer: current evidence and future directions

Antibody-drug conjugates (ADCs) are a rapidly evolving class of antitumor drugs and have already revolutionized the treatment strategy of many hematologic and solid cancers. So far, trastuzumab emtansine (T-DM1), trastuzumab deruxtecan (T-DXd), sacituzumab govitecan (SG) and datopotamab deruxtecan (Dato-DXd) are the four ADCs that have been approved by US food and drug administration (FDA) in treatment of breast cancer, and SKB264 has been approved by Chinese national medical products administration (NMPA). Many ADCs for treatment of breast cancer are currently being tested in late-phase clinical trials, with several encouraging results achieved recently. However, major issues arise during the use of ADCs, including emergence of acquired resistance, occurrence of treated-related toxicities, and identification of biomarkers of response and resistance. ADCs are being increasingly tested in combination with other agents, and novel next-generation ADC development is progressing rapidly. A better understanding of the design and development of ADCs will promote ADC development for cancer treatment. In this review, we aim to provide a broad overview of the design and the recent advances of ADCs in breast cancer. We also propose several notable future directions of ADCs in treatment of breast cancer.

A retrospective study to investigate the prevalence and describe the clinicopathological characteristics, treatments, and outcomes of HER2-low Breast Cancer in Taiwan

BACKGROUND

The binary classification of human epidermal growth factor receptor 2 (HER2) as HER2-positive [immunohistochemistry (IHC) 2+/in situ hybridization (ISH)+ or 3+] or HER2-negative (IHC 0, 1+, or 2+/ISH-) has been reassessed due to the efficacy of an anti-HER2 antibody-drug conjugate-Trastuzumab Deruxtecan in HER2-low (IHC 1+ or 2+/ISH-) unresectable/metastatic breast cancer (mBC) patients. However, little is known about the prevalence and outcomes of HER2-low mBC in Taiwan.

METHODS

This retrospective study rescored archived HER2 IHC slides of HER2-negative unresectable/mBC patients diagnosed from 2017 to 2020. The HER2-low prevalence (among HER2-negative), clinicopathological characteristics, treatments, and outcomes of HER2-low unresectable/mBC patients were investigated.

RESULTS

Of the rescored HER2-negative cohort, HER2-low prevalence was 61.2 % (186/304) and slightly higher in slides tested by non-Ventana 4B5 assays (vs. Ventana 4B5) and slides from metastatic sites (vs. primary tumors). The overall percentage agreement between historical and rescored IHC was high (90.1 %). For HR+/HER2-low patients, endocrine therapies were frequently used in the first two lines of treatment, while chemotherapy was more common after the second-line treatment. Chemotherapy was the predominant treatment for HR-/HER2-low patients. Time to next treatment (TTNT) and overall survival (OS) since the first-line systemic therapy were longer in the HR+/HER2-low (N = 138) compared to HR-/HER2-low (N = 48) cohorts (median TTNT: 7.6 vs. 4.8 months; median OS: 37.7 vs. 18.8 months).

CONCLUSION

This study suggested that two-thirds of HER2-negative unresectable/mBC patients in Taiwan were HER2-low. Reassessing the HER2 status of HER2-negative patients could improve treatment strategies with the evolving HER2 classification paradigm.

Signal detection and safety analysis of three tyrosine kinase inhibitors for HER-2 positive breast cancer: a retrospective study based on the FAERS database

Objective

To identify adverse event (ADE) signals of three tyrosine kinase inhibitors (TKIs) (Tucatinib, Lapatinib, and Neratinib) used for HER-2 positive breast cancer by utilizing the FAERS database, and to analyze their safety profiles to provide references for clinical risk management.

Methods

Data from the FAERS database spanning Q1 2015 to Q3 2024 were retrieved, including reports where Tucatinib, Lapatinib, or Neratinib was identified as the primary suspect drug. Disproportionality analysis (ROR, PRR) and the Comprehensive Standard method were employed to detect potential ADE signals. The distribution of ADEs across different System Organ Classifications (SOCs) was also analyzed.

Results

A total of 7,848 ADE reports were analyzed, identifying 557 significant signals. The primary ADEs were concentrated in gastrointestinal disorders, general conditions, administration site reactions, and skin and subcutaneous tissue disorders. Neratinib exhibited higher gastrointestinal toxicity, Lapatinib was associated with notable skin toxicities, and Tucatinib showed specific adverse reactions linked to combination therapies.

Conclusion

The three TKIs demonstrated distinct ADE signal profiles, with gastrointestinal, systemic, and skin toxicities being the major areas of concern. Future research should validate these findings and develop effective management strategies to enhance treatment safety and improve the quality of life for HER-2 positive breast cancer patients.

Antibody-Drug Conjugates: The Toxicities and Adverse Effects That Emergency Physicians Must Know

Antibody-drug conjugates are novel antineoplastic agents whose use is expanding, both in terms of the number of drugs and the number of patients being treated. This article reviews the known toxicities and complications of antibody-drug conjugates that are currently approved for the treatment of cancer in the United States, with a focus on their emergency presentation and management. Similar to many other cancer therapies, most antibody-drug conjugates can cause diarrhea, nausea/vomiting, rash, peripheral neuropathy, and cytopenia, which are generally treated following standard-of-care. Interstitial lung disease, which may mimic pneumonia and cause respiratory failure and death, has been seen with trastuzumab deruxtecan and mirvetuximab soravtansine; emergency treatment of this condition includes oxygenation, ventilatory support, and corticosteroids. Inotuzumab ozogamicin and gemtuzumab ozogamicin are both associated with sinusoidal obstruction syndrome, a potentially fatal liver dysfunction that presents with weight gain, fluid overload, and jaundice. Abnormal liver function tests in patients who have been recently treated with these agents should be cautiously evaluated. Cardiac adverse events with antibody-drug conjugates are rare, but trastuzumab emtansine and trastuzumab deruxtecan may cause a decrease in cardiac contractility, and heart rate corrected QT interval prolongation is a rare effect of trastuzumab deruxtecan. Ocular adverse events, especially blurred vision, and keratopathy, are common with mirvetuximab soravtansine and tisotumab vedotin. Progressive multifocal leukoencephalopathy has been reported with brentuximab vedotin and polatuzumab vedotin. Tumor lysis syndrome may occur after treatment with gemtuzumab ozogamicin, polatuzumab vedotin, and brentuximab vedotin. Patients receiving enfortumab vedotin or brentuximab vedotin may develop hyperglycemia, sometimes presenting as diabetic ketoacidosis. Tisotumab vedotin and trastuzumab emtansine are associated with bleeding; although it is minor in most cases, severe bleeding and intracranial hemorrhage have occurred. Several antibody-drug conjugates can cause an anaphylactoid infusion-related reaction, which occurs most commonly during or soon after infusion but may be delayed up to 24 hours. Further research is needed to establish the real-world incidence of rare complications and how often patients with these complications present to the emergency department.

Practical clinical management of ocular adverse events related to Antibody-Drug Conjugates in gynaecological malignancies

BACKGROUND

The advent of Antibody-Drug Conjugates (ADC) represents a significant advancement in targeted therapy for gynaecological malignancies. However, the ocular toxicities associated with ADCs, particularly Tisotumab Vedotin (TV) and Mirvetuximab Soravtansine (MIRV) necessitate effective mitigation in order to optimise patient care.

METHODS

This review synthesises findings from clinical trials to delineate the spectrum of ocular adverse events induced by ADCs. The analysis focuses on the incidence, onset, severity and reversibility of adverse events. It examines the underlying mechanisms of toxicity and provides management strategies based on study protocols.

RESULTS

Adverse events mainly impact the anterior ocular segment, resulting in conjunctivitis and keratopathy. They affect up to 56 % of patients treated with MIRV and 50 to 60 % of those receiving TV. Symptoms like blurred vision, dryness and pain hinder the patient's quality of life. Events are CTCAE grade 3 or higher in less than 10 % of cases. The median time to onset is 1.3 months. However, ocular toxicity may appear up to 10 months after treatment initiation, indicating a need for prolonged vigilance. Primary prophylaxis calls for local corticotherapy, lubricants and in some cases, vasoconstrictors. Despite the potential for severity, most cases are reversible with local treatment and transient dose reduction and/or delay. Close monitoring is crucial for early detection and subsequent management.

CONCLUSIONS

Clinicians ought to be cognizant of the potential ocular toxicity of ADCs. Proactive prophylaxis, patient education and a multidisciplinary approach involving ophthalmologists are paramount to minimising the impact of these AEs. Further research is essential to measure the real outcome of preventive strategies and balance their benefits with potential short and long-term risks.

Tucatinib and trastuzumab in HER2-mutated metastatic breast cancer: a phase 2 basket trial

Human epidermal growth factor receptor 2 (HER2, also known as ERBB2) signaling promotes cell growth and differentiation, and is overexpressed in several tumor types, including breast, gastric and colorectal cancer. HER2-targeted therapies have shown clinical activity against these tumor types, resulting in regulatory approvals. However, the efficacy of HER2 therapies in tumors with HER2 mutations has not been widely investigated. SGNTUC-019 is an open-label, phase 2 basket study evaluating tucatinib, a HER2-targeted tyrosine kinase inhibitor, in combination with trastuzumab in patients with HER2-altered solid tumors. The study included a cohort of 31 heavily pretreated female patients with HER2-mutated metastatic breast cancer who were also HER2 negative per local testing. Hormone receptor (HR)-positive patients also received fulvestrant. The overall response rate (primary endpoint) was 41.9% (90% confidence interval (CI): 26.9-58.2). Secondary endpoints of duration of response and progression-free survival were 12.6 months (90% CI: 4.7 to not estimable) and 9.5 months (90% CI: 5.4-13.8), respectively. No new safety signals were detected. Responses were observed across various HER2 mutations, including mutations in the tyrosine kinase and extracellular domains. The chemotherapy-free regimen of tucatinib and trastuzumab showed clinically meaningful antitumor activity with durable responses and favorable tolerability in heavily pretreated patients with HER2 mutations. These data support further investigation of HER2-targeted therapies in this patient population. ClinicalTrials.gov registration: NCT04579380 .

Evaluating the safety of antibody-drug conjugates in lung cancer: A systematic review and meta-analysis

BACKGROUND

Antibody-drug conjugates (ADC) have emerged as a promising treatment for lung cancer. However, their safety profile requires further analysis. This study assessed adverse events (AE) in patients with lung cancer treated with ADCs, with particular focus on differences in pathological types, therapeutic options, and drug components.

METHODS

Prospective trials from various databases up to June 11, 2024, that analyzed treatment-emergent AEs (TEAEs), treatment-related AEs (TRAEs), mortality, and drug discontinuation were identified. Incidence rates were pooled using a random effects model, and their corresponding 95% confidence intervals (CIs) were calculated.

RESULTS

The analysis included 28 studies with 3,127 participants. The pooled incidence of all-grade TEAEs and TRAEs was 98.9 % and 91.4 %, respectively, whereas that of grade ≥ 3 TEAEs and TRAEs was 65.9 % and 41.7 %, respectively. The gastrointestinal system was frequently involved, albeit predominantly in low grades. Hematological system involvement was prevalent in grade ≥ 3 AEs, with respiratory system disorders being more prevalent in severe AEs. Respiratory system disorders were the primary cause of death and drug discontinuation. Subgroup analyses revealed higher incidences of AEs in SCLC than in NSCLC, in combination therapies than in monotherapies, and in ADCs with cleavable linkers. ADCs targeting delta-like protein 3 or carrying pyrrolobenzodiazepine dimer as payloads exhibit higher incidences of grade ≥ 3 TEAEs than those targeting HER2.

CONCLUSION

Effective managing ADC toxicities is crucial in lung cancer treatment, with AE incidence and profiles varying by cancer pathology, treatment regimen, and ADC components. Close monitoring of symptoms associated with gastrointestinal, infection, and respiratory systems is essential. PROSPERO registration number: CRD42024546210.

ACE-Breast-02: a randomized phase III trial of ARX788 versus lapatinib plus capecitabine for HER2-positive advanced breast cancer

This phase III trial aimed to compare ARX788, a site-specific, construct-homogeneous antibody-drug conjugate, with lapatinib plus capecitabine in patients with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer (ABC) who had progressed on one line of trastuzumab based regimen. Eligible patients were randomized (1:1) to receive ARX788 (1.5 mg/kg, IV, Q3W) or lapatinib plus capecitabine (LC: lapatinib 1250 mg QD; capecitabine 1000 mg/m2 BID, days 1-14, Q3W) and stratified by prior chemotherapy lines (0-1 versus >1) and visceral metastasis (yes versus no). The primary outcome was progression-free survival (PFS) assessed by a blinded independent central review (BICR). A total of 441 patients were randomly assigned to receive either ARX788 (n = 221) or LC (n = 220). The median PFS was 11.3 (95% confidence interval [CI], 8.4-13.8) months with ARX788 compared with 8.2 (95% CI, 6.9-8.7) months with LC, as per BICR (hazard ratio [HR] 0.64, p = 0.0006). Frequencies of treatment-related adverse events (TRAEs) of any grade were 98.6% and 99.1% for ARX788 and LC, respectively. Grade ≥3 TRAEs were 41.4% and 40.0%, respectively, the most common adverse events were blurred vision (12.3%), dry eye (9.1%), keratopathy (5.9%), and interstitial lung disease (ILD, 5.9%) with ARX788; hand-foot syndrome (18.1%) and hypokalemia (5.1%) with LC; all the hematological and gastrointestinal events of grade ≥3 with ARX788 were less than 3%. Six treatment-related deaths occurred, with three cases possibly related to ILD. ARX788 significantly improved PFS compared with LC in patients with HER2-positive ABC with a distinct toxicity profile, supporting it as a potential treatment option.

Trastuzumab Duocarmazine in Pretreated Human Epidermal Growth Factor Receptor 2-Positive Advanced or Metastatic Breast Cancer: An Open-Label, Randomized, Phase III Trial (TULIP)

PURPOSE

Human epidermal growth factor receptor 2 (HER2)-targeted therapy is standard of care for HER2-positive (HER2+) breast cancer, but most patients develop progressive disease with persistent HER2 expression. No definitive treatment guidance currently exists beyond second line. Trastuzumab duocarmazine (T-Duo) is a third-generation, HER2-targeted antibody-drug conjugate that demonstrated efficacy and acceptable safety in phase I studies of heavily pretreated patients with HER2+/HER2-low breast cancer.

METHODS

In this open-label, randomized, phase III trial, T-Duo was compared with physician's choice (PC) in patients with unresectable locally advanced/metastatic HER2+ breast cancer with progression during/after ≥2 HER2-targeted therapies or after trastuzumab emtansine (T-DM1). The primary endpoint was progression-free survival (PFS) by blinded independent central review.

RESULTS

In total, 437 patients were randomly assigned 2:1 to T-Duo (n = 291) or PC (n = 146). The median age was 56.0 years (range, 24-86); most patients (93.6%) had metastatic disease. The median time from diagnosis of metastatic disease to trial entry was 3.5 years; the median number of prior HER2-targeted therapies in metastatic setting was three. The median PFS was 7.0 months (95% CI, 5.4 to 7.2) with T-Duo versus 4.9 months (95% CI, 4.0 to 5.5; hazard ratio [HR], 0.64 [95% CI, 0.49 to 0.84]; P = .002) with PC. PFS benefit was maintained across most predefined subgroups. The median overall survival (first analysis) was 20.4 (T-Duo) versus 16.3 months (PC; HR, 0.83 [95% CI, 0.62 to 1.09]; P = .153). Objective response rate was 27.8% (T-Duo) versus 29.5% (PC); other efficacy end points-clinical benefit rate, duration of response, and reduction in target lesion measurement-tended to favor T-Duo. Grade ≥3 treatment-emergent adverse events occurred in 52.8% (T-Duo) versus 48.2% (PC).

CONCLUSION

Treatment with T-Duo was manageable, but tolerability was affected by prevalent ocular toxicity, leading to a higher discontinuation rate in the T-Duo arm. T-Duo significantly reduced the risk of progression in patients with advanced HER2+ breast cancer who have progressed during/after ≥2 HER2-targeted therapies or after T-DM1.

Review of the clinical status of cardiotoxicity of HER-2 positive breast cancer targeted therapeutic drugs

Breast cancer is a major health challenge for women worldwide, and human epidermal growth factor receptor 2 (HER-2)-positive breast cancers have a relatively high incidence and are highly aggressive. Targeted therapeutic agents, represented by trastuzumab, have been effective in improving the survival rate of HER-2-positive breast cancer patients. However, in clinical applications, this type of targeted drugs exhibits varying degrees of cardiotoxicity, and the mechanism of their cardiotoxicity is currently unclear. In this paper, we classify them into three categories: monoclonal antibodies (mAbs), small-molecule tyrosine kinase inhibitors (TKIs), and antibody-drug conjugate (ADCs). We list the evidence of cardiotoxicity for various drugs based on current clinical trials and summarize their corresponding epidemiological profiles. We also discuss the regulation of cardiotoxicity from three perspectives: clinical biomarkers of cardiotoxicity, permissive cardiotoxicity, and the current status of cardiotoxicity regulation.

Impact of trastuzumab emtansine (T-DM1) on spleen volume in patients with HER2-positive metastatic breast cancer

BACKGROUND

Trastuzumab emtansine (T-DM1) is a novel therapy for human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer, combining the targeted action of trastuzumab with the cytotoxic effects of emtansine. Although T-DM1 has demonstrated greater efficacy and safety compared to traditional therapies, concerns about hepatotoxicity and spleen-related complications have arisen.

METHODS

We conducted a retrospective study of 64 HER2-positive metastatic breast cancer patients treated with T-DM1 at our institution. Patients underwent computed tomography or magnetic resonance imaging at baseline and during treatment cycles. Spleen volume, portal vein diameter, and laboratory values were compared between baseline and 12 months after T-DM1 treatment.

RESULTS

Median spleen volume significantly increased from 201 cm3 (IQR, 157-275) at baseline to 291 cm3 (IQR, 215-420) after 12 months of T-DM1 treatment (P < 0.001). Spleen enlargement was observed in 87.5% of patients, while no significant alteration was detected in portal vein diameter. The change in spleen volume was positively correlated with changes in serum globulin levels, liver enzymes, and bilirubin levels, but did not impact survival outcomes.

CONCLUSIONS

T-DM1 therapy in HER2-positive metastatic breast cancer leads to significant spleen enlargement and systemic biochemical changes. Future studies should focus on elucidating the long-term implications of these findings and optimizing monitoring strategies for spleen-related complications.

Therapeutic Management in Elderly Male Breast Cancer Patients: A Scoping Review

PURPOSE OF REVIEW

Male breast cancer (MBC) is a rare entity which often arises in elderly people. Aim of this review is to evaluate the principal issues related to MBC in elderly, because the therapeutic management of disease is not only related to the biological behavior of the tumor, but also to the comorbidities and frailty of older population. A scoping literature review was performed on Pubmed and Cochrane Database using the following keywords: therapeutic management/ male/ breast cancer/ elderly patients. Papers published before 2000, not edited in English or French language, or not related to the main topic, were excluded. Only articles related to therapeutic issues in MBC and including more than 10 elderly (≥ 65 years) patients were selected for the qualitative outcome analysis.

RECENT FINDINGS

36 papers regarding surgery, radiotherapy, systemic therapy, racial disparities and therapeutic management in retrospective series of MBC in elderly were examined in details. MBC has a different biological behavior and a poorer prognosis than female, especially in cases with positive nodes at diagnosis. Elderly MBC patients have often larger tumors in more advanced stages at the time of diagnosis compared with younger patients. In spite of the advanced tumors at presentation, older patients present often cancers with more favorable biological characteristics, but they receive less guideline-concordant curative treatments (as adequate lymph node staging or adjuvant radiation therapy) compared to women. Moreover, racial differences in treatment of older MBC were observed. Therapeutic management of MBC in elderly patients is a subject rarely addressed in literature. Our review highlighted differences in the treatment and in guidelines-concordance for elderly MBC patients. Adequate geriatric assessment and use of therapeutic schemes adapted to age and comorbidities can avoid under/overtreatment, contributing to a better standard of care in this frail population.

Antibody-drug conjugates in breast cancer

Antibody-drug conjugates (ADCs) have garnered significant attention as an innovative therapeutic strategy in cancer treatment. The mechanism of action for ADCs involves the targeted delivery of antibodies to specific receptors, followed by the release of cytotoxic payloads directly into tumor cells. In recent years, ADCs have made substantial progress in the treatment of breast cancer (BC), particularly demonstrating significant efficacy in the human epidermal growth factor receptor-2 (HER-2)-positive subgroup. Clinical evidence indicates that ADCs have notably improved treatment efficacy and survival outcomes for BC patients. However, challenges such as drug toxicities and the emergence of drug resistance necessitate further research and discussion. In this paper, we will summarize the advances in ADCs targeting various receptors in BC patients and explore the challenges and future directions in this field. We anticipate that the increasing availability of ADCs will lead to more effective and personalized treatment options for BC patients.

Strategies to enhance management of HER2-positive breast cancer in the elderly: an expert consensus perspective

Therapeutic decision-making for older patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer highlights the importance of a comprehensive geriatric assessment (CGA). This assessment considers the functional status, comorbidities, and relevant conditions of the patient, and allows for an estimation of life expectancy, but it does not facilitate individualized treatment plans. There are also other challenges to consider related to the cardiac toxicity of the treatments and the under-representation of older patients in clinical trials. The Oncogeriatrics Section of the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica, SEOM), the Spanish Group for Breast Cancer Research (Grupo Español de Investigación en Cáncer de Mama, GEICAM) and the Spanish Group of Study, Treatment and other Experimental Strategies in Solid Tumours (Grupo Español de Estudio, Tratamiento y otras Estrategias Experimentales en Tumores Sólidos, SOLTI) have gathered an expert committee to evaluate the scientific evidence on the management of older patients with HER2-positive breast cancer and to establish recommendations based on a comprehensive review of the existing literature. These recommendations underscore the importance of individualizing treatment plans based on the patient's physical status and tolerability to maximize efficacy while minimizing toxicity. Emphasis is placed on adapting neoadjuvant and adjuvant therapies according to geriatric assessment and specific patient needs. A careful selection of treatment schedules for advanced stages is needed to improve survival and quality of life, assuming that scientific evidence in this age group is limited.

Hematological toxicities in antibody-drug conjugates related with breast cancer: a pharmacovigilance study using FDA adverse event reporting system database

OBJECTIVE

The trastuzumab emtansine, trastuzumab deruxtecan, and sacituzumab govitecan are antibody-drug conjugates (ADCs) that have demonstrated efficacy in the treatment of breast cancer. Nonetheless, these ADCs can also induce severe toxicities in various organ systems, particularly the hematological system. Therefore, this study evaluated the hematological toxicities associated with ADCs in breast cancer based on real-world data.

METHODS

Data were extracted from the FDA Adverse Event Reporting System (FAERS) database, spanning from 2014 Q1 to 2023 Q3. Further analysis was done on the hematological toxicities related with ADCs, including their features, onset time, and fatality proportion.

RESULTS

Out of 10,976 adverse event reports, 1895 hematotoxicity reports (17.26%) were analyzed. All ADCs exhibited positive safety signals for hematological toxicities, as indicated by reporting odds ratios and the information component. Unexpected significant adverse events, including splenomegaly, immune thrombocytopenia, hemolytic anemia, and hemolytic anemia, that were discovered in the medication label transpired during our data mining. The median time-to-onset of these toxicities was 13 days (interquartile range [IQR] 7-54.75), and the fatality proportion associated with hematological toxicities and ADCs was 17.41%.

CONCLUSION

The study indicated that hematological toxicities caused by ADCs preferentially emerge early and may have catastrophic consequences. Early detection and management of these hematological toxicities associated with ADC is essential.

Recent advances of antibody-drug conjugates in treating breast cancer with different HER2 status

Despite the availability of multiple treatment options for breast cancer, challenges such as adverse events, drug resistance, and disease progression persist for patients. The identification of human epidermal growth factor receptor 2 (HER2) as an oncogenic driver in a subset of breast cancers, alongside the development of HER2-targeted therapies, has significantly improved the prognosis of HER2-amplified breast cancers. However, therapeutic options remain limited for HER2-overexpressing or HER2-negative breast cancers. In response to this gap, antibody-drug conjugates (ADCs) have emerged as a promising approach. ADCs combine the specificity of monoclonal antibodies with the cytotoxic effects of chemotherapy, which allows for the targeted delivery of a cytotoxic payload to cancer cells. ADCs have been used as adjuvant chemotherapeutic treatments and salvage therapies across various breast cancer subtypes, which have greatly improved the prognosis of breast cancer patients. Numerous ongoing clinical trials seek to optimize dosing strategies and identify patient populations that would benefit most from ADCs. This review presents an updated and comprehensive overview of emerging investigational ADCs for treating breast cancer patients with various HER2 subtypes. These ADCs are spearheading a new era in targeted cancer therapy, promising to innovate treatment paradigms for both HER2-positive and HER2-low breast cancers.

Drug induced lupus associated with Trastuzumab emtansine in a patient with metastatic breast cancer

INTRODUCTION

Ado-trastuzumab emtansine (T-DM1) is employed in the treatment of patients with HER2-positive breast cancer. The most common side effects are fatigue, diarrhoea, anaemia, transaminase elevation and drug-induced thrombocytopenia. This report describes a patient with metastatic breast cancer who developed drug-induced lupus due to T-DM1.

CASE REPORT

A 54-year-old woman was diagnosed with breast cancer in March 2018. She underwent modified radical mastectomy and axillary lymph node dissection (pT2N1aM0). Following supraclavicular lymph node metastasis in May 2018, she received 8 cycles of docetaxel, trastuzumab, and pertuzumab. In December 2020, the patient presented with axillary and intra-abdominal lymph node metastases, along with bone metastases observed on PET/CT scan. Treatment with T-DM1 and zoledronic acid was initiated. After 18 months on T-DM1, she developed drug-induced lupus. Her symptoms resolved with hydroxychloroquine treatment and discontinuation of T-DM1.

DISCUSSION

Drug-induced lupus is a clinical syndrome that shares similar features with systemic lupus erythematosus (SLE). The majority of patients present with symptoms such as arthralgia and myalgia. Hydralazine and procainamide are high-risk drugs for drug-induced lupus. Symptoms usually develop after months or years of use, but may also develop suddenly. Our patient also received TDM-1 treatment for 18 months. We present a case of TDM-1-associated drug-induced lupus in a patient with metastatic breast cancer. This is the first case of TDM-1-related drug-induced lupus reported in the literature.

Expert recommendations on treatment sequencing and challenging clinical scenarios in human epidermal growth factor receptor 2-positive (HER2-positive) metastatic breast cancer

Human epidermal growth factor receptor 2 (HER2) overexpression and/or ERBB2 gene amplification occurs in approximately 15-20% of breast cancers and is associated with poor prognosis. While the introduction of HER2-targeted therapies has significantly improved survival in patients with HER2-positive metastatic breast cancer, the incidence of brain metastases has increased due to patients living longer. Current recommendations sequence treatments by line of therapy, as well as by the status of brain metastases in patients with HER2-positive breast cancer. However, in the third-line treatment setting and beyond, there is a lack of clarity of the preferred choice of therapy. In clinical practice, clinicians may also encounter challenging scenarios where the optimal therapeutic approach has not been defined by clinical studies, so there is a need for clarity in such situations. Two consensus meetings of expert oncologists (12 from Europe and one from Canada) were convened to discuss these scenarios. We subsequently developed this article to present an overview of current treatment recommendations for HER2-positive metastatic breast cancer and give practical guidance on addressing challenging scenarios in a real-world setting. Based on our clinical experience, we provide a unanimous consensus concerning the treatment of elderly patients as well as those with brain-only metastases, leptomeningeal disease, oligometastatic disease, central nervous system oligo-progressive disease or ERBB2-mutant disease. We also discuss how to combine HER2-targeted therapy with endocrine therapy in patients with HER2-positive/hormone-receptor-positive disease, considerations for potential discontinuation of HER2-targeted therapy in patients with long-term remission and how to treat patients whose metastatic biopsy no longer confirms their HER2-positive status.

Antibody-Drug Conjugates in Breast Cancer: The Road Towards Biologically-Informed Selection and Sequencing

PURPOSE OF REVIEW

In this review, we discuss evidence supporting the use of antibody-drug conjugates (ADCs) in breast cancer treatment, describe novel ADCs and combination regimens under development, and examine our current understanding of resistance mechanisms and biomarkers to guide ADC selection and sequencing.

RECENT FINDINGS

Three ADCs have proven benefit in patients with metastatic breast cancer: trastuzumab emtansine (T-DM1), trastuzumab deruxtecan (T-DXd), and sacituzumab govitecan (SG). There are over two hundred investigational ADCs on the horizon, as pre-clinical studies work to identify novel ADC targets and structures. In this new frontier, translational efforts are underway to personalize the use of ADCs, including refining HER2 quantification and elucidating genetic, epigenetic, and post-translational mechanisms of resistance. ADCs have provided important treatment options for patients with breast cancer. As patients become eligible for more than one ADC, there is an unmet need to identify the appropriate timing and sequence of these therapies to maximize their efficacy.

Advancements in research and clinical management of interstitial lung injury associated with ADC drugs administration in breast cancer

Antibody-drug conjugates (ADCs) represent a novel class of targeted anti-tumor medications that utilize the covalent linkage between monoclonal antibodies and cytotoxic agents. This unique mechanism combines the cytotoxic potency of drugs with the targeting specificity conferred by antigen recognition. However, it is essential to recognize that many ADCs still face challenges related to off-target toxicity akin to cytotoxic payloads, as well as targeted toxicity and other potential life-threatening adverse effects, such as treatment-induced interstitial lung injury. Currently, of the four approved ADC drugs for breast cancer, several reports have documented post-treatment lung injury-related fatalities. As a result, treatment-induced interstitial lung injury due to ADC drugs has become a clinical concern. In this review article, we delve into the factors associated with ADC-induced interstitial lung injury in patients with advanced-stage breast cancer and highlight strategies expected to decrease the incidence of ADC-related interstitial lung injury in the years ahead. These efforts are directed at enhancing treatment outcomes in both advanced and early-stage cancer patients while also providing insights into the development and innovation of ADC drugs and bolstering clinicians' understanding of the diagnosis and management of ADC-associated interstitial lung injury.

Influence of antibody-drug conjugate cleavability, drug-to-antibody ratio, and free payload concentration on systemic toxicities: A systematic review and meta-analysis

While in theory antibody drug conjugates (ADCs) deliver high-dose chemotherapy directly to target cells, numerous side effects are observed in clinical practice. We sought to determine the effect of linker design (cleavable versus non-cleavable), drug-to-antibody ratio (DAR), and free payload concentration on systemic toxicity. Two systematic reviews were performed via PubMed search of clinical trials published between January 1998-July 2022. Eligible studies: (1) clinical trial for cancer therapy in adults, (2) ≥ 1 study arm included a single-agent ADC, (3) ADC used was commercially available/FDA-approved. Data was extracted and pooled using generalized linear mixed effects logistic models. 40 clinical trials involving 7,879 patients from 11 ADCs, including 9 ADCs with cleavable linkers (N = 2,985) and 2 with non-cleavable linkers (N = 4,894), were included. Significantly more composite adverse events (AEs) ≥ grade 3 occurred in patients in the cleavable linkers arm (47%) compared with the non-cleavable arm (34%). When adjusted for DAR, for grade ≥ 3 toxicities, non-cleavable linkers remained independently associated with lower toxicity for any AE (p = 0.002). Higher DAR was significantly associated with higher probability of grade ≥ 3 toxicity for any AE. There was also a significant interaction between cleavability status and DAR for any AE (p = 0.002). Finally, higher measured systemic free payload concentrations were significantly associated with higher DARs (p = 0.043). Our results support the hypothesis that ADCs with cleavable linkers result in premature payload release, leading to increased systemic free payload concentrations and associated toxicities. This may help to inform future ADC design and rational clinical application.

Predictive Factors of Antibody-Drug Conjugate Treatment in Metastatic Breast Cancer: A Narrative Review

Antibody-drug conjugates (ADCs) have revolutionized the treatment landscape for metastatic breast cancer, offering targeted delivery of cytotoxic agents with improved efficacy and tolerability compared to conventional chemotherapy. This narrative review explores key predictive factors influencing the efficacy of ADCs, focusing on HER2-targeted therapies, such as trastuzumab emtansine and trastuzumab deruxtecan, as well as sacituzumab govitecan for triple-negative breast cancer. HER2 expression, TROP-2 levels, hormone receptor status, and the tumor microenvironment emerge as critical biomarkers for patient selection and therapeutic outcomes. Additionally, we discuss resistance mechanisms, such as antigen loss, impaired drug internalization, and the role of circulating tumor DNA in predicting ADC response. Finally, future perspectives on the sequential use of ADCs and potential combination therapies are highlighted, along with emerging agents targeting alternative antigens like HER3 and LIV-1. Overall, identifying predictive biomarkers and overcoming resistance mechanisms are essential for optimizing the use of ADCs in metastatic breast cancer, thereby improving patient outcomes.

A Review of Current and Future Antibody Drug Conjugates in Breast Cancer

OPINION STATEMENT

Antibody-drug conjugates (ADCs) are a novel class of anti-cancer agents that have changed the standard of care for patients with breast cancer. Their targeted approach delivers potent anti-cancer drugs to cancer cells bearing specific surface antigens, thereby maximizing anti-cancer effects and minimizing systemic toxicity. Currently, there are three ADCs available for use in breast cancer: trastuzumab emtansine for HER2 positive breast cancer (early stage and metastatic), trastuzumab deruxtecan for HER2 positive and HER2 low breast cancer (metastatic) and sacituzumab govitecan for triple negative and hormone receptor positive (HR +), HER2 negative breast cancer(metastatic). Trials have shown that these drugs have improved both progression free survival and overall survival in the metastatic setting, and trastuzumab emtansine has improved overall survival in early-stage breast cancer as well. The future of this class of compounds is very exciting. This field is rapidly evolving with new ADCs being investigated and clinical trials looking at the use of known ADCs in earlier stage disease.

Evaluation of the Safety and Efficacy of Trastuzumab Emtansine (T-DM1) Biosimilar in Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Breast Cancer: Findings From a Single-Center Retrospective Analysis in India

Background Human epidermal growth factor receptor 2 (HER2)-positive breast cancer is a highly aggressive subtype characterized by a high recurrence rate. Trastuzumab emtansine (T-DM1), an antibody-drug conjugate targeting HER2, has shown improved outcomes; however, its effectiveness in cases with brain metastases remains unclear. The T-DM1 biosimilar has emerged as a cost-effective treatment option. Objectives The primary objective was to assess the efficacy of the T-DM1 biosimilar by evaluating progression-free survival (PFS) and overall survival (OS). The secondary objective focused on analyzing the safety profile, including the incidence and characteristics of adverse events (AEs) during T-DM1 treatment. Materials and methods In this retrospective, single-center study, 30 HER2-positive breast cancer patients were treated with T-DM1 at a dose of 3.6 mg/kg, administered intravenously every 21 days. The primary outcomes measured were PFS, OS, time to treatment failure (TTF), complete response (CR), and partial response (PR). The secondary endpoint was the documentation of AEs. Results All patients, with a median age of 57 years, received prior HER2-targeted therapy, and five (16.6%) patients had undergone brain radiotherapy. CR was achieved in 20 (66.6%) patients, while 10 (33.3%) patients attained PR. PFS, OS, and TTF were approximately 14, 24, and 13 months, respectively. Common adverse events included elevated transaminases, anemia, and thrombocytopenia, the majority of which were controllable and reversible. Conclusion This study provides important insights into the efficacy and safety of the T-DM1 biosimilar. The findings indicate that T-DM1 is effective in enhancing OS and managing advanced HER2-positive breast cancer, including selective patients with brain metastases. The results highlight the T-DM1 biosimilar as a cost-effective treatment option with an expected safety and tolerability profile.

Dermatologic toxicities of antibody-drug conjugates

Antibody-drug conjugates (ADCs) are a new and emerging category of oncologic treatments that combine the target specificity of a monoclonal antibody with a cytotoxic payload. These drugs are associated with unique cutaneous toxicities that vary across agents. Currently, there are eleven ADCs with regulatory approval for solid and liquid tumors and over 80 ADCs currently in clinical development, it is critical for dermatologists to recognize and appropriately mitigate the cutaneous toxicities associated with these therapies. This clinical review will summarize the novel mechanisms and indications of approved ADCs, discuss dermatologic toxicities demonstrated in clinical trials and postmarketing studies, and impart recognition and management guidance when encountering these reactions to help maintain patients safely and comfortably on their medications.

Updates in Treatment of HER2-positive Metastatic Breast Cancer

OPINION STATEMENT

The therapeutic landscape for HER2-positive metastatic breast cancer has exploded in the last two decades following the initial advent of trastuzumab, a monoclonal antibody. While the first line treatment has remained a combination of dual HER2 blockade with taxane chemotherapy, we now have several exciting options in the second line and beyond. The introduction of antibody-drug conjugates, in specific trastuzumab deruxtecan, has resulted in the best progression-free survival among patients with this subtype of breast cancer. Given the excellent outcomes of these drugs, clinical trials are now evaluating the role of ADCs in the front-line setting in previously untreated patients. In addition, there are also clinical trials evaluating the role of other targets in patients with HER2-positive cancers, including PI3KCA mutations, PD-L1 and CDK4/6. Given the predilection for brain metastases in this population, there is enthusiasm to identify the optimal combination of effective treatments. Tucatinib, capecitabine, and trastuzumab combination represent one such promising strategy. With the increasing longevity of these patients, important clinical questions include optimal treatment sequencing, the role of de-escalation of treatment in excellent responders, and the associated financial toxicity. Despite the aggressive nature of this subtype of breast cancer, the outcomes continue to improve for these patients with the evolving treatments.

Role of antibody drug conjugates in the treatment of patients with breast cancer brain metastases

Breast cancer remains a leading cause of brain metastases (BM), which carry a poor prognosis. The current approach to managing BMs in breast cancer patients involves a combination of local therapies (surgery, radiotherapy) and systemic treatments. Developing newer antibody-drug conjugates (ADCs) has sparked a revolution in metastatic breast cancer (MBC) care. ADCs such as ado-trastuzumab emtansine, trastuzumab deruxtecan, and sacituzumab govitecan have demonstrated significant improvement in patient outcomes and are standard of care in the treatment of MBC. Most of the ADC registration studies included patients with stable BMs but excluded individuals with active BM, making intracranial (IC) response assessment a challenge. Promising data has recently emerged, suggesting relevant IC activity for certain ADCs and ongoing studies in patients with active BM that will expand our knowledge. This review aims to summarize the effectiveness of approved ADCs as well as promising new ADCs in development for breast cancer with BM.

Adjuvant Trastuzumab Emtansine Versus Paclitaxel Plus Trastuzumab for Stage I Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer: 5-Year Results and Correlative Analyses From ATEMPT

PURPOSE

Long-term outcomes of patients with stage I human epidermal growth factor receptor 2 (HER2)-positive breast cancer receiving adjuvant trastuzumab emtansine (T-DM1) remain undefined, and prognostic predictors represent an unmet need.

METHODS

In the ATEMPT phase II trial, patients with stage I centrally confirmed HER2-positive breast cancer were randomly assigned 3:1 to adjuvant T-DM1 for 1 year or paclitaxel plus trastuzumab (TH). Coprimary objectives were to compare the incidence of clinically relevant toxicities between arms and to evaluate invasive disease-free survival (iDFS) with T-DM1. Correlative analyses included the HER2DX genomic tool, multiomic evaluations of HER2 heterogeneity, and predictors of thrombocytopenia.

RESULTS

After a median follow-up of 5.8 years, 11 iDFS events were observed in the T-DM1 arm, consistent with a 5-year iDFS of 97.0% (95% CI, 95.2 to 98.7). At 5 years, the recurrence-free interval (RFI) was 98.3% (95% CI, 97.0 to 99.7), the overall survival was 97.8% (95% CI, 96.3 to 99.3), and the breast cancer-specific survival was 99.4% (95% CI, 98.6 to 100). Comparable iDFS was observed with T-DM1 irrespective of tumor size, hormone receptor status, centrally determined HER2 immunohistochemical score, and receipt of T-DM1 for more or less than 6 months. Although ATEMPT was not powered for this end point, the 5-year iDFS in the TH arm was 91.1%. Among patients with sufficient tissue for HER2DX testing (n = 187), 5-year outcomes significantly differed according to HER2DX risk score, with better RFI (98.1% v 81.8%, hazard ratio [HR], 0.10, P = .01) and iDFS (96.3% v 81.8%, HR, 0.20, P = .047) among patients with HER2DX low-risk versus high-risk tumors, respectively.

CONCLUSION

Adjuvant T-DM1 for 1 year leads to outstanding long-term outcomes for patients with stage I HER2-positive breast cancer. A high HER2DX risk score predicted a higher risk of recurrence in ATEMPT.

Evolving Treatment Landscape for Advanced Esophageal and Gastroesophageal Junction Adenocarcinoma

PURPOSE OF REVIEW

This review highlights advances and recent changes in the treatment paradigm for advanced esophageal adenocarcinoma (EAC) and gastroesophageal junction adenocarcinoma (GEJAC).

RECENT FINDINGS

Chemotherapy remains the backbone of treatment for advanced EAC/GEJAC. New targets/agents include immunotherapy, HER-2, claudin18.2, and FGFR2b, with various mechanisms (CAR-T, bispecific mAB, ADCs) altering the treatment landscape against these targets. The approaches to these targets may act together, in sequence, and even synergistically to improve outcomes. Herein, we review the state of the field, including highlighting ongoing clinical trials and additional emerging agents and approaches.

Guidance for Canadian Breast Cancer Practice: National Consensus Recommendations for the Systemic Treatment of Patients with HER2+ Breast Cancer in Both the Early and Metastatic Setting

Human epidermal growth factor receptor 2-positive (HER2+) breast cancer is an aggressive subtype of breast cancer associated with a poor prognosis when sub-optimally treated. Recent advances include new and effective targeted therapies that have significantly improved outcomes for patients. Despite these advances, there are significant gaps across Canada, underscoring the need for evidence-based consensus guidance to inform treatment decisions. Addressing these gaps is crucial to ensuring that effective therapies are integrated into clinical practice, so as to improve the lives of patients affected by this aggressive form of breast cancer. The Research Excellence, Active Leadership (REAL) Canadian Breast Cancer Alliance is a standing nucleus committee of clinical-academic oncologists across Canada and Breast Cancer Canada, a patient organization. The mandate of this group is to provide evidence-based guidance on best practices in the management of patients with breast cancer. These consensus recommendations were developed using a modified Delphi process with up to three rounds of anonymous voting. Consensus was defined a priori as ≥75% of voters agreeing with the recommendation as written. There are 9 recommendations in the early setting; 7 recommendations in the metastatic setting; and 10 recommendations for patients with brain metastases.

Antibody-Drug Conjugates for the Treatment of Non-Small Cell Lung Cancer with Central Nervous System Metastases

Antibody-drug conjugates (ADCs) represent an emerging class of targeted anticancer agents that have demonstrated impressive efficacy in numerous cancer types. In non-small cell lung cancer (NSCLC), ADCs have become a component of the treatment armamentarium for a subset of patients with metastatic disease. Emerging data suggest that some ADCs exhibit impressive activity even in central nervous system (CNS) metastases, a disease site that is difficult to treat and associated with poor prognosis. Herein, we describe and summarize the existing evidence surrounding ADCs in NSCLC with a focus on CNS activity.

PI3K Mutation Profiles on Exons 9 (E545K and E542K) and 20 (H1047R) in Mexican Patients With HER-2 Overexpressed Breast Cancer and Its Relevance on Clinical-Pathological and Survival Biological Effects

Background: Trastuzumab resistance is associated with overexpressing the human epidermal growth factor receptor 2 (HER-2), which results from the altered phosphoinositide 3-kinase (PI3K) pathway in breast cancer patients. Objective: We quantified the frequency of PI3K enzyme single and double-point mutations in Mexican patients with HER-2 overexpressing breast cancer and its association with clinical-pathological variables. Methods: We embedded HER-2 breast samples in paraffin from 60 patients, extracted their DNA, and evaluated PI3K mutations in 49 HER-2-positive breast tumors. We focused on mutations for one exon 20 (H1047R) and two exon 9 PI3K (E545K, E542K) hotspots and characterized them as single and double-point mutations. The mean patient follow-up was 86 months. Results: Of 49 patients who tested positive for HER-2 breast cancer, 14.28% showed mutations in PI3K, 71.42% single-point, and 28.56% double-point mutations. We found single-point mutations in H1047R (42.85%) and E545K (28.57%). Only two patients exhibited double-point mutations: one in E542K/E545K and another in H1047R/E545K (14.28% each). Although we observed lower survival in patients with mutations in PI3K, we did not find a significant association between these factors (p = 0.191). However, single and double-point mutations in PI3K were significantly associated with the clinical stages of diagnosis and tumor size (p = 0.027 and p = 0.04, respectively). Conclusion: Single and double-point mutations in PI3K are related to tumor size and advanced clinical-pathological traits in Mexican patients with HER-2 overexpression, and future molecular studies are necessary to understand these findings.

Cardiac toxicity of HER-2 targeting antibody-drug conjugates: overview and clinical implications

Antibody-drug conjugates (ADCs) have recently emerged as a promising therapeutic option that combine the specificity of monoclonal antibodies and the cytotoxic effect of chemotherapy. With numerous ADCs approved and on the market, a particular concern of ADCs that target HER-2 has been their cardiac side effects, in view of the crucial role of HER-2 in cardiac development and physiology. While rarely toxic and generally safe, numerous publications have outlined the consistent association of trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd) with the development of cardiac toxicity. Despite not being clinically relevant in most cases, cardiac baseline evaluation, monitoring and early detection of cardiac adverse events remain pivotal with HER-2 targeting ADCs. This review aims to summarize and better characterize the complete cardiac toxicity profile of HER-2 ADCs, with the goal of improving clinical understanding of this adverse event, leading to better recognition, monitoring and management.

Breast Cancer Brain Metastasis: A Comprehensive Review

The mechanisms underlying breast cancer brain metastasis (BCBM) development are complex, and its clinical presentation varies depending on the number, location, and size of brain metastases. Common symptoms include headache, neurologic deficits, and seizures. Diagnosis of BCBM typically relies on neuroimaging techniques, such as magnetic resonance imaging and computed tomography scans. Local therapies, such as surgery and stereotactic radiosurgery, can be used to control tumor growth and relieve symptoms. Whole-brain radiotherapy has been a mainstay of treatment for BCBM, but its use has been associated with cognitive decline. Systemic therapy with chemotherapy and targeted agents plays an increasingly important role in the management of BCBM. Novel agents, such as human epidermal growth factor receptor 2 (HER2)-targeted therapies and tyrosine kinase inhibitors, have shown promising results in improving survival for patients with HER2-positive and triple-negative BCBM. This comprehensive review synthesizes current knowledge, clinical insights, and evolving paradigms to provide a robust understanding and roadmap for optimizing the diagnosis and management of BCBM.

A signal-seeking phase 2 study of Trastuzumab emtansine in tumours harbouring HER2 amplification or mutation

This single-arm phase II non-randomised trial (ACTRN12619001265167) evaluated trastuzumab emtansine in solid cancers with HER2 amplification or mutation detected by comprehensive genomic profiling. The primary objective was objective response (OR), while secondary objectives included the time to progression (TTP) on study to TTP on prior therapy ratio, progression-free survival (PFS) and overall survival (OS). The cohort included 16 tumours with HER2 mutations (group 1) and 16 with HER2 amplification (group 2). After 17 months median follow-up, ORs occurred in 19% of group 1 (1 salivary gland carcinoma (SGC), 2 lung cancers) and 25% of group 2 (3 SGCs, 1 uterine carcinoma). Fourteen of 29 TTP-evaluable patients achieved a TTP ratio ≥1.3, including 10 without an OR. Median PFS and OS were 4.5 (95% CI 2.1-7.0) and 18.2 months (95% CI 8.1-not reached) respectively. Trastuzumab emtansine showed modest ORs and a favourable change in disease trajectory in select HER2-altered solid cancers.

Efficacy of Lapatinib Plus Capecitabine After TDM-1 in HER2-Positive Metastatic Breast Cancer Patients

Different targeted therapy options exist for treating HER2-positive metastatic breast cancer patients. This study evaluated the efficacy and tolerability of the lapatinib plus capecitabine combination after TDM-1 in HER2-positive metastatic breast cancer patients. We retrospectively evaluated the HER2-positive metastatic breast cancer patients' data. The patients who progressed after trastuzumab-based chemotherapy and TDM-1 were included in the study. We used the Kaplan-Meier for survival analysis. Eighteen patients were involved in the study. The average age was 48 (range 31-65). De novo metastatic patient's number was 5 (27.8%). The most common metastatic sites were liver (50%), lung (44.4%), and brain (44.4%), respectively. All patients were previously treated with trastuzumab + chemotherapy and TDM-1. Also, seven (38.9%) patients received hormonotherapy and twelve (66.7%) patients received palliative radiotherapy. The complete response ratio was 5.6%, partial response 11.8%, and stable response 29.4%. Median progression-free survival was found as 5.5 (95% CI, 3.2-7.7) months. The hematological and non-hematological toxicity ratio was 41.2% and 52.9%, respectively. Grade 3-4 toxicity (diarrhea, anemia, and mucositis) was observed in four (22.2%) patients. The median OS duration was 8.2 months (95% CI, 4.3-12.0). Treatment options are limited in heavily pretreated HER2-positive breast cancer patients. Despite a small number of patients, this study showed that the lapatinib plus capecitabine combination was effective and well-tolerated in heavily pretreated HER2-positive breast cancer patients after TDM-1.

Antibody-drug conjugates for breast cancer: a bibliometric study and clinical trial analysis

BACKGROUND

Breast cancer (BC) remains the most commonly malignancy among women worldwide. Although early-stage BC typically presents with curative possibilities, advanced-stage disease, especially with metastasis, is significantly limited in terms of effective therapeutic interventions, thereby establishing it as the second leading cause of cancer-related deaths in women. Antibody-Drug Conjugates (ADCs) establish a groundbreaking class of anti-neoplastic agents characterized by high specificity and targeting precision. These agents have been significant in reshaping the therapeutic approach to breast cancer, especially those subtypes with overexpression of the Human Epidermal Growth Factor Receptor 2 (HER2). Comprising monoclonal antibodies, cytotoxic payloads, and conjugative linkers, ADCs function by specifically targeting antigens on cancer cells, thereby facilitating the intracellular delivery of the toxic payload. The present investigation endeavors to synthesize existing primary research outcomes through rigorous bibliometric and data analytical approaches, thereby elucidating the current research landscape, delineating research foci, and identifying potential avenues for future innovation.

METHODS

For bibliometric analysis, a comprehensive data set comprising 2181 entries related to ADCs in breast cancer was retrieved from the Web of Science Core Collection (WoSCC) spanning the years 1999 to 2023. This data was further filtered from the Science Citation Index Expanded (SCI-Expanded). Analysis software tools such as CiteSpace and VOSviewer were employed for multifaceted analyses such as trends of publications, contributions of countries, and burst analytics. In the dimension of clinical trials, we interrogated databases including ClinicalTrials.gov ( https://www.

CLINICALTRIALS

gov ) and the WHO International Clinical Trials Registry Platform (ICTRP) ( https://trialsearch.who.int ). A total of 239 clinical trials were initially sourced, among which, 175 were from ClinicalTrials.gov and 64 from ICTRP. After repetitive and correlation-based screening, 119 trials specifically addressing ADC therapeutic strategies in breast cancer were included. Analytical algorithms were executed using Microsoft-based software to evaluate treatment paradigms, emergent research themes, and progress.

RESULTS

Our investigations signify a growing trend of research on ADCs, with consistent advancements in scientific achievements. The analysis revealed that variables such as economic stratification of nations, healthcare investment paradigms, and disease incidence rates serve as significant determinants in shaping research output. Geographically, the United States emerged as the predominant contributor to the research corpus (36.56%), closely followed by China (21.33%). The underpinning of research accomplishments was found to be significantly bolstered by advancements in molecular biology, immunology, and genetic research. Moreover, the advent of nuclear magnetic resonance diagnostic modalities has contributed saliently to the diagnostic and therapeutic management of breast cancer.

CONCLUSION

Our study provides a comprehensive overview of the ADC research landscape through rigorous bibliometric and clinical trial evaluations. At present, the ADC arena has witnessed the successful development and FDA approval of 14 distinct agents, substantially improving the clinical outcomes for a broad spectrum of oncological patients. Future research imperatives may include the exploration of ADCs targeting mutated oncoproteins, dual-specificity ADCs, combination payload strategies, peptide-drug conjugates (PDCs), and non-internalizing ADC modalities. With sustained academic and clinical focus, the ADC domain is poised for transformative advancements in targeted therapeutics across a variety of malignancies.

Antibody-drug conjugates in cancer therapy: mechanisms and clinical studies

Antibody-drug conjugates (ADCs) consist of monoclonal antibodies that target tumor cells and cytotoxic drugs linked through linkers. By leveraging antibodies' targeting properties, ADCs deliver cytotoxic drugs into tumor cells via endocytosis after identifying the tumor antigen. This precise method aims to kill tumor cells selectively while minimizing harm to normal cells, offering safe and effective therapeutic benefits. Recent years have seen significant progress in antitumor treatment with ADC development, providing patients with new and potent treatment options. With over 300 ADCs explored for various tumor indications and some already approved for clinical use, challenges such as resistance due to factors like antigen expression, ADC processing, and payload have emerged. This review aims to outline the history of ADC development, their structure, mechanism of action, recent composition advancements, target selection, completed and ongoing clinical trials, resistance mechanisms, and intervention strategies. Additionally, it will delve into the potential of ADCs with novel markers, linkers, payloads, and innovative action mechanisms to enhance cancer treatment options. The evolution of ADCs has also led to the emergence of combination therapy as a new therapeutic approach to improve drug efficacy.

Depicting Biomarkers for HER2-Inhibitor Resistance: Implication for Therapy in HER2-Positive Breast Cancer

HER2 (human epidermal growth factor receptor 2) is highly expressed in a variety of cancers, including breast, lung, gastric, and pancreatic cancers. Its amplification is linked to poor clinical outcomes. At the genetic level, HER2 is encoded by the ERBB2 gene (v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2), which is frequently mutated or amplified in cancers, thus spurring extensive research into HER2 modulation and inhibition as viable anti-cancer strategies. An impressive body of FDA-approved drugs, including anti-HER2 monoclonal antibodies (mAbs), antibody-drug conjugates (ADCs), and HER2-tyrosine kinase inhibitors (TKIs), have demonstrated success in enhancing overall survival (OS) and disease progression-free survival (PFS). Yet, drug resistance remains a persistent challenge and raises the risks of metastatic potential and tumor relapse. Research into alternative therapeutic options for HER2+ breast cancer therefore proves critical for adapting to this ever-evolving landscape. This review highlights current HER2-targeted therapies, discusses predictive biomarkers for drug resistance, and introduces promising emergent therapies-especially combination therapies-that are aimed at overcoming drug resistance in the context of HER2+ breast cancer.

Gastrointestinal Toxicity of Antibody Drug Conjugates (ADCs) in Metastatic Breast Cancer: A Pooled Analysis

Trastuzumab emtansine (T-DM1), sacituzumab govitecan (SG), and trastuzumab deruxtecan (T-DXd) are three ADCs approved for the treatment of metastatic breast cancer (MBC). Since gastrointestinal toxicities have been commonly observed with these drugs in clinical trials, a pooled analysis evaluating gastrointestinal adverse events (AEs) in patients with MBC treated with ADCs in clinical trials was performed. PubMed, Embase, and the Cochrane Library were searched from inception until May 2023 for phase II and III clinical trials reporting frequency and severity of gastrointestinal AEs during treatment with ADCs. Data were retrieved for nausea, vomiting, diarrhea, constipation, and abdominal pain: overall and grade 3-4 toxicity rates according to NCI-CTCAE were collected and expressed as proportions. A pre-specified subgroup analysis according to the agent was also carried out. Fourteen studies, comprising 5608 patients, were included in the analysis. Gastrointestinal AEs were frequently registered with SG and T-DXd. A significantly higher frequency of nausea (65.6% with SG, 75% with T-DXd), vomiting (43.7% with SG, 45% with T-DXd), and diarrhea (59.7% with SG, 29% with T-DXd) was noticed with these ADCs compared to TDM-1. Furthermore, diarrhea was more frequently associated with SG (grade 3 in 7.5% of patients), while constipation and abdominal pain were less common. Gastrointestinal AEs, notably nausea and diarrhea, were frequently reported by MBC patients treated with SG and T-DXd in clinical trials. Since these ADCs are administered continuously until disease progression or occurrence of unbearable AEs, gastrointestinal toxicity may have a negative impact on patient quality of life. Therefore, appropriate management of gastrointestinal AEs is mandatory to ensure treatment efficacy and adherence.

[Treatment-related adverse events associated with antibody drug conjugate in breast cancer]

Therapeutic options for breast cancer have recently been enriched by new antibody-drug conjugates (ADC), which are now being utilized across all known molecular subtypes. ADCs represent a groundbreaking class of therapies that combine a cytotoxic agent with a monoclonal antibody via a combination molecule (linker). The primary objective is to selectively deliver chemotherapy to cells expressing the target antigen, thereby enhancing the therapeutic index. Trastuzumab-emtansine marked the pioneering use of this approach for HER2-overexpressed breast cancer. More recently, trastuzumab-deruxtecan and sacituzumab-govitecan have demonstrated efficacy in progression-free survival and overall survival in HER2-overexpressed and HER2-low breast cancer for the former, and HER2-non-overexpressed (including HER-low) for the latter. Numerous other ADCs are currently under development in breast cancer. While ADCs were initially designed to widen the therapeutic index and mitigate toxicities, managing ADC-related adverse events in the clinical setting remains a challenge. This review article aims to provide an overview of the toxicity profiles of these drugs already in current clinical practice or under development, drawing from results observed in various studies.