OA03.03 Datopotamab Deruxtecan (Dato-DXd; DS-1062), a TROP2 ADC, in Patients With Advanced NSCLC: Updated Results of TROPION-PanTumor01 Phase 1 Study

TROP2 Is Associated with Primary Resistance to Immune Checkpoint Inhibition in Patients with Advanced Non-Small Cell Lung Cancer

PURPOSE

Mechanisms of primary resistance to inhibitors of the programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) signaling axis in non-small cell lung cancer (NSCLC) are still poorly understood. While some studies suggest the involvement of trophoblast cell surface antigen 2 (TROP2) in modulating tumor cell resistance to therapeutic drugs, its specific role in the context of PD-1/PD-L1 axis blockade is not definitively established.

EXPERIMENTAL DESIGN

We performed high-throughput analysis of transcriptomic data from 891 NSCLC tumors from patients treated with either the PD-L1 inhibitor atezolizumab or chemotherapy in two large randomized clinical trials. To confirm our results at the protein level, we complemented this transcriptional approach by performing a multiplex immunofluorescence analysis of tumor tissue samples as well as a proteomic profiling of plasma.

RESULTS

We observed a significant association of TROP2 overexpression with worse progression-free survival and overall survival on PD-L1 blockade, independent of other prognostic factors. Importantly, we found increased TROP2 expression to be predictive of survival in patients treated with atezolizumab but not chemotherapy. TROP2 overexpression was associated with decreased T-cell infiltration. We confirmed these results at the proteomic level both on tumor tissue and in plasma.

CONCLUSIONS

Our results suggest an important contribution of TROP2 expression to the primary resistance to PD-L1 blockade in NSCLC. TROP2-biomarker-based strategy may be relevant in selecting patients with NSCLC who are more likely to benefit from a combination of immunotherapy and an anti-TROP2 agent.

A narrative review of antibody-drug conjugates in EGFR-mutated non-small cell lung cancer

In the past 15 years, non-small cell lung cancer (NSCLC) treatment has changed with the discovery of mutations and the development of new targeted therapies and immune checkpoint inhibitors. Epidermal growth factor receptor (EGFR) was the first mutation in NSCLC to have a drug that was FDA-approved in 2013. Osimertinib, a third-generation tyrosine kinase inhibitor, is approved as first-line therapy for advanced NSCLC and in the adjuvant setting for Stage IB-IIIA resected NSCLC. However, resistance to osimertinib is inevitably an issue, and thus patterns of resistance to EGFR-mutated NSCLC have been studied, including MET amplification, EGFR C797X-acquired mutation, human epidermal growth factor 2 (HER2) amplification, and transformation to small cell and squamous cell lung cancer. Current management for EGFR-mutated NSCLC upon progression of EGFR TKI is limited at this time to chemotherapy and radiation therapy, sometimes in combination with the continuation of osimertinib. Antibody-drug conjugates (ADCs) are made up of a monoclonal antibody linked to a cytotoxic drug and are an increasingly popular class of drug being studied in NSCLC. Trastuzumab deruxtecan has received accelerated FDA approval in HER2-mutated NSCLC. ADCs offer a possible solution to finding a new treatment that could bypass the intracellular resistance mechanism. In this review article, we summarize the mechanism of ADCs and investigational ADCs for EGFR-mutated NSCLC, which include targets to MET amplification, HER3, Trop2, and EGFR, along with other ADC targets being investigated in NSCLC, and discuss future directions that may arise with ADCs in EGFR-mutated NSCLC.

First-in-Human, Phase I Dose-Escalation and Dose-Expansion Study of Trophoblast Cell-Surface Antigen 2-Directed Antibody-Drug Conjugate Datopotamab Deruxtecan in Non-Small-Cell Lung Cancer: TROPION-PanTumor01

PURPOSE

This first-in-human, dose-escalation and dose-expansion study evaluated the safety, tolerability, and antitumor activity of datopotamab deruxtecan (Dato-DXd), a novel trophoblast cell-surface antigen 2 (TROP2)-directed antibody-drug conjugate in solid tumors, including advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Adults with locally advanced/metastatic NSCLC received 0.27-10 mg/kg Dato-DXd once every 3 weeks during escalation or 4, 6, or 8 mg/kg Dato-DXd once every 3 weeks during expansion. Primary end points were safety and tolerability. Secondary end points included objective response rate (ORR), survival, and pharmacokinetics.

RESULTS

Two hundred ten patients received Dato-DXd, including 180 in the 4-8 mg/kg dose-expansion cohorts. This population had a median of three prior lines of therapy. The maximum tolerated dose was 8 mg/kg once every 3 weeks; the recommended dose for further development was 6 mg/kg once every 3 weeks. In patients receiving 6 mg/kg (n = 50), median duration on study, including follow-up, and median exposure were 13.3 and 3.5 months, respectively. The most frequent any-grade treatment-emergent adverse events (TEAEs) were nausea (64%), stomatitis (60%), and alopecia (42%). Grade ≥3 TEAEs and treatment-related AEs occurred in 54% and 26% of patients, respectively. Interstitial lung disease adjudicated as drug-related (two grade 2 and one grade 4) occurred in three of 50 patients (6%). The ORR was 26% (95% CI, 14.6 to 40.3), and median duration of response was 10.5 months; median progression-free survival and overall survival were 6.9 months (95% CI, 2.7 to 8.8 months) and 11.4 months (95% CI, 7.1 to 20.6 months), respectively. Responses occurred regardless of TROP2 expression.

CONCLUSION

Promising antitumor activity and a manageable safety profile were seen with Dato-DXd in heavily pretreated patients with advanced NSCLC. Further investigation as first-line combination therapy in advanced NSCLC and as monotherapy in the second-line setting and beyond is ongoing.

[Diagnosis and management of interstitial lung disease induced by antibody-drug conjugates in breast cancer: A French expert opinion paper]

Interstitial lung disease (ILD) has been reported with many cancer drugs including some recent antibody-drug conjugates (ADCs). The mechanisms of ILD induced by many chemotherapy drugs, other drug classes and ADCs used in cancer, including breast cancer, are not clearly elucidated. In the absence of specific clinical or radiological signs, the diagnosis of drug-induced ILD is often a diagnosis of exclusion. When present, the most frequent symptoms are respiratory signs (cough, dyspnea, chest pain) and general signs (fatigue, fever). Any suspicion of ILD should be evaluated by imaging and, if in doubt, the CT scan should be evaluated by a pulmonologist and a radiologist. A network of multidisciplinary experts for proactive early management of ILD is important, including oncologist, radiologist, pulmonologist, infectious disease specialist and nurses. Patient education is essential to report new or exacerbated lung symptoms and prevent high-grade ILD. Study drug is discontinued temporarily or permanently according to ILD severity and type of ADC. For asymptomatic cases (Grade 1), the efficacy of corticosteroids is not clearly established; for higher grades, the benefit/risk balance of long-term corticosteroid therapy should be considered for the dose and treatment duration. Hospitalization and oxygen supplementation are required for severe cases (Grades 3-4). For patient follow-up, the expertise of a pulmonologist is necessary with repeated chest scans, spirometry and DLCO. Preventing ADC-induced ILDs and evolution to high grade rests on a network of multidisciplinary experts for assessment of individual risk factors, early management, close follow-up and patient education.

Novel systemic therapies in the management of tyrosine kinase inhibitor-pretreated patients with epidermal growth factor receptor-mutant non-small-cell lung cancer

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are the standard first-line option for non-small-cell lung cancer (NSCLC) harboring active EGFR mutations. The overall survival of patients with advanced NSCLC has improved dramatically with the development of comprehensive genetic profiles and targeted therapies. However, resistance inevitably occurs, leading to disease progression after approximately 10-18 months of EGFR-TKI treatment. Platinum-based chemotherapy is the standard treatment for patients who have experienced disease progression while undergoing EGFR-TKI treatment, but its efficacy is limited. The management of extensively pretreated patients with EGFR-mutant NSCLC is becoming increasingly concerning. New agents have shown encouraging efficacy in clinical trials for this patient population, including fourth-generation EGFR-TKIs, EGFR-TKIs combined with counterpart targeted drugs, and novel agents such as antibody-drug conjugates. We review current efforts to manage extensively pretreated patients with EGFR-mutant NSCLC.

Toxicity profile of antibody-drug conjugates in breast cancer: practical considerations

Antibody-drug conjugates (ADCs) represent a novel and evolving class of antineoplastic agents, constituted by monoclonal antibody linked to biologically active drugs, delivering cytotoxic compounds at the tumor site, reducing the likelihood of systemic exposure and toxicity. They are generally well tolerated, nevertheless some predictable adverse reactions need careful monitoring and timely approach. These include neutropenia, nausea and vomiting, alopecia, diarrhea, left ventricular dysfunction, ILD/pneumonitis. The mechanisms leading to drug-associated toxicities are summarized, and prophylaxis protocols and appropriate management strategies are proposed, based on current literature. This review aims to collect the most updated evidence on toxicities potentially occurring during breast cancer treatment with approved or under clinical investigation (advanced stage) ADCs. A focus is dedicated to monitoring protocols and clinical management, aimed at preventing and/or promptly address relevant problems, in order to avoid premature discontinuation or improper dose reduction.

What to do after immune-checkpoint inhibitors failure in advanced non-small cell lung cancer: an expert opinion and review

INTRODUCTION

Immune-checkpoint inhibitors (IO) have significantly improved outcomes of patients with non-oncogene-addicted non-small cell lung cancer (NSCLC), becoming the first-line agents for advanced disease. However, resistance remains a significant clinical challenge, limiting their effectiveness.

AREAS COVERED

Hereby, we addressed standard and innovative therapeutic approaches for NSCLC patients experiencing progression after IO treatment, discussing the emerging resistance mechanisms and the ongoing efforts to overcome them. In order to provide a complete overview of the matter, we performed a comprehensive literature search across prominent databases, including PubMed, EMBASE (Excerpta Medica dataBASE), and the Cochrane Library, and a research of the main ongoing studies on clinicaltrials.gov.

EXPERT OPINION

The dynamics of progression to IO, especially in terms of time to treatment failure and burden of progressive disease, should guide the best subsequent management, together with patient clinical conditions. Long-responders to IO might benefit from continuation of IO beyond-progression, in combination with other treatments. Patients who experience early progression should be treated with salvage CT in case of preserved clinical conditions. Finally, patients who respond to IO for a considerable timeframe and who later present oligo-progression could be treated with a multimodal approach in order to maximize the benefit of immunotherapy.

Antibody-drug conjugates (ADCs) targeting TROP-2 in lung cancer

INTRODUCTION

The advent of antibody-drug conjugates (ADCs) represents a renewed strategy in the era of precision oncology. Several epithelial tumors harbor overexpression of the trophoblast cell-surface antigen 2 (TROP-2), which represents a predictor of poor prognosis and a promising target for anticancer therapy.

AREAS COVERED

In this review, we aim to collect the available preclinical and clinical data regarding anti-TROP-2 ADCs in lung cancer obtained through extensive literature research and screening of the available abstract/posters presented at recent meetings.

EXPERT OPINION

Anti-TROP-2 ADCs represent an innovative upcoming weapon against both non-small cell lung cancer and small cell lung cancer subtypes, pending the results of several ongoing trials. The proper combination and placement of this agent throughout the lung cancer treatment pathway, the identification of potentially predictive biomarkers of benefit, as well as the optimal management and impact of peculiar toxicity (i.e. interstitial lung disease) are the next questions to be answered.

Antibody-Drug Conjugates in Lung Cancer: Recent Advances and Implementing Strategies

Antibody-drug conjugates (ADCs) are one of the fastest-growing oncology therapeutics, merging the cytotoxic effect of conjugated payload with the high specific ability and selectivity of monoclonal antibody targeted on a specific cancer cell membrane antigen. The main targets for ADC development are antigens commonly expressed by lung cancer cells, but not in normal tissues. They include human epidermal growth factor receptor 2, human epidermal growth factor receptor 3, trophoblast cell surface antigen 2, c-MET, carcinoembryonic antigen-related cell adhesion molecule 5, and B7-H3, each with one or more specific ADCs that showed encouraging results in the lung cancer field, more in non-small-cell lung cancer than in small-cell lung cancer histology. To date, multiple ADCs are under evaluation, alone or in combination with different molecules (eg, chemotherapy agents or immune checkpoint inhibitors), and the optimal strategy for selecting patients who may benefit from the treatment is evolving, including an improvement of biomarker understanding, involving markers of resistance or response to the payload, besides the antibody target. In this review, we discuss the available evidence and future perspectives on ADCs for lung cancer treatment, including a comprehensive discussion on structure-based drug design, mechanism of action, and resistance concepts. Data were summarized by specific target antigen, biology, efficacy, and safety, differing among ADCs according to the ADC payload and their pharmacokinetics and pharmacodynamics properties.

Antibody-Drug Conjugates for Lung Cancer: Payloads and Progress

Antibody Drug Conjugates (ADCs) are a novel class of therapeutic that structurally comprise an antibody directed at a tumor epitope connected via a linker to a cytotoxic payload that have shown significant antitumor activity across a range of malignancies including lung cancer. In this article we review the pharmacology of ADCs, describe results of trials with ADCs directed at targets in lung cancer including Trophoblast cell-surface antigen 2(TROP2), HER3, MET, Carcinoembryonic antigen-related cell adhesion molecular 5(CECAM-5) and HER2. Trastuzumab Deruxtecan (also known as DS-8201a or T-DXd) an ADC directed at HER2 recently became the first ADC to receive FDA approval in lung cancer, on the basis of its activity in tumors with HER2 mutations, demonstrated in the Destiny-Lung01 and Lung02 trials.

Antibody-drug conjugates in lung cancer: dawn of a new era?

Antibody-drug conjugates (ADCs) are one of fastest growing classes of oncology drugs in modern drug development. By harnessing the powers of both cytotoxic chemotherapy and targeted therapy, ADCs are unique in offering the potential to deliver highly potent cytotoxic agents to cancer cells which express a pre-defined cell surface target. In lung cancer, the treatment paradigm has shifted dramatically in recent years, and now ADCs are now joining the list as potential options for lung cancer patients. Since 2020, the first ADC for NSCLC patients has been FDA-approved (trastuzumab deruxtecan) and two ADCs have been granted FDA Breakthrough Therapy Designation, currently under evaluation (patritumab deruxtecan, telisotuzumab vedotin). Furthermore, several early-phase trials are assessing various novel ADCs, either as monotherapy or in combinations with advanced lung cancer, and more selective and potent ADCs are expected to become therapeutic options in clinic soon. In this review, we discuss the structure and mechanism of action of ADCs, including insights from pre-clinical work; we summarize the ADCs' recent progress in lung cancer, describe toxicity profiles of ADCs, and explore strategies designed to enhance ADC potency and overcome resistance. In addition, we discuss novel ADC strategies of interest in lung cancer, including non-cytotoxic payloads, such as immunomodulatory and anti-apoptotic agents.

Pooled analysis of drug-related interstitial lung disease and/or pneumonitis in nine trastuzumab deruxtecan monotherapy studies

Introduction

This pooled analysis of nine phase I and II trastuzumab deruxtecan (T-DXd) monotherapy studies described drug-related interstitial lung disease (ILD)/pneumonitis in patients treated with T-DXd.

Methods

Patients who received T-DXd across nine studies were included. Investigator-assessed ILD/pneumonitis events were retrospectively reviewed by an independent adjudication committee; events adjudicated as drug-related ILD/pneumonitis are summarized.

Results

The analysis included 1150 patients (breast cancer, 44.3%; gastric cancer, 25.6%; lung cancer, 17.7%; colorectal cancer, 9.3%; other cancer, 3.0%). Median treatment duration was 5.8 (range, 0.7-56.3) months, with a median of 4 (range, 1-27) prior lines of therapy. The overall incidence of adjudicated drug-related ILD/pneumonitis was 15.4% (grade 5, 2.2%). Most patients with ILD/pneumonitis experienced low-grade events (grade 1 or 2, 77.4%); 87.0% had their first event within 12 months [median, 5.4 (range, <0.1-46.8) months] of their first dose of T-DXd. Based on data review, adjudicated ILD/pneumonitis onset occurred earlier than identified by investigators for 53.2% of events [median difference in onset date, 43 (range, 1-499) days]. Stepwise Cox regression identified several baseline factors potentially associated with increased risk of adjudicated drug-related ILD/pneumonitis: age <65 years, enrollment in Japan, T-DXd dose >6.4 mg/kg, oxygen saturation <95%, moderate/severe renal impairment, presence of lung comorbidities, and time since initial diagnosis >4 years.

Conclusions

In this pooled analysis of heavily treated patients, the incidence of ILD/pneumonitis was 15.4%, with most being low grade and occurring in the first 12 months of treatment. The benefit–risk of T-DXd treatment is positive; however, some patients may be at increased risk of developing ILD/pneumonitis, and further investigation is needed to confirm ILD/pneumonitis risk factors. Close monitoring and proactive management of ILD/pneumonitis are warranted for all.

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Interstitial lung disease (ILD)/pneumonitis is a significant adverse event related to trastuzumab deruxtecan (T-DXd).

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This pooled analysis of nine T-DXd monotherapy studies evaluated ILD/pneumonitis risk in 1150 heavily pretreated patients.

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Overall incidence of adjudicated T-DXd-related ILD/pneumonitis was 15.4% (grade 1 or 2, 77.4%; grade 5, 2.2%).

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Within 12 months of their first T-DXd dose, 87.0% of patients had their first event [median, 5.4 (range, <0.1-46.8) months].

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Proactive monitoring and prompt diagnosis and management are important to improving ILD/pneumonitis event outcomes.

[Current Progress and Future Developments of Antibody Drug Conjugates in Lung Cancer]

Antibody drug conjugates (ADCs) are a novel class of anti-cancer drugs, which combined the specificity of monoclonal antibodies with the cytotoxic palyload via the linkers. Many ADCs have not only verified impressive activity in a variety of cancers, including breast cancer and hematological system tumors, but also in lung cancer. The aim of this study was to provide informations for practice by summarizing the mechanism of action, clinical application and problems and challenges of ADCs.
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Multidisciplinary clinical guidance on trastuzumab deruxtecan (T-DXd)-related interstitial lung disease/pneumonitis-Focus on proactive monitoring, diagnosis, and management

Trastuzumab deruxtecan (T-DXd; DS-8201) is an antibody-drug conjugate targeting human epidermal growth factor receptor 2. Interstitial lung disease (ILD)/pneumonitis is an adverse event associated with T-DXd; in most cases, it is low grade (grade ≤ 2) and can be treated effectively but may develop to be fatal in some instances. It is important to increase patient and provider understanding of T-DXd-related ILD/pneumonitis to improve patient outcomes. Drug-related ILD/pneumonitis is a diagnosis of exclusion; other possible causes of lung injury/imaging findings must be ruled out for an accurate diagnosis. Symptoms can be nonspecific, and identifying early symptoms is challenging; therefore, diagnosis is often delayed. We reviewed characteristics of patients who developed T-DXd-related ILD/pneumonitis and its patterns, produced multidisciplinary guidelines on diagnosis and management, and described areas for future investigation. Ongoing studies are collecting data on T-DXd-related ILD/pneumonitis to further our understanding of its clinical patterns and mechanisms. SEARCH STRATEGY AND SELECTION CRITERIA: References were identified based on the guidelines used by the authors in treating interstitial lung disease and pneumonitis. Searches of the authors' own files were also completed. A search of PubMed with the search terms (trastuzumab deruxtecan) AND (interstitial lung disease) AND (guidelines) was conducted on November 1, 2021, with no restrictions based on publication date, and the two articles yielded by the search were included.

Antibody drug conjugate: the "biological missile" for targeted cancer therapy

Antibody–drug conjugate (ADC) is typically composed of a monoclonal antibody (mAbs) covalently attached to a cytotoxic drug via a chemical linker. It combines both the advantages of highly specific targeting ability and highly potent killing effect to achieve accurate and efficient elimination of cancer cells, which has become one of the hotspots for the research and development of anticancer drugs. Since the first ADC, Mylotarg^® (gemtuzumab ozogamicin), was approved in 2000 by the US Food and Drug Administration (FDA), there have been 14 ADCs received market approval so far worldwide. Moreover, over 100 ADC candidates have been investigated in clinical stages at present. This kind of new anti-cancer drugs, known as “biological missiles”, is leading a new era of targeted cancer therapy. Herein, we conducted a review of the history and general mechanism of action of ADCs, and then briefly discussed the molecular aspects of key components of ADCs and the mechanisms by which these key factors influence the activities of ADCs. Moreover, we also reviewed the approved ADCs and other promising candidates in phase-3 clinical trials and discuss the current challenges and future perspectives for the development of next generations, which provide insights for the research and development of novel cancer therapeutics using ADCs.

Antibody-drug conjugates: Smart chemotherapy delivery across tumor histologies

As distinct cancer biomarkers have been discovered in recent years, a need to reclassify tumors by more than their histology has been proposed, and therapies are now tailored to treat cancers based on specific molecular aberrations and immunologic markers. In fact, multiple histology-agnostic therapies are currently adopted in clinical practice for treating patients regardless of their tumor site of origin. In parallel with this new model for drug development, in the past few years, several novel antibody-drug conjugates (ADCs) have been approved to treat solid tumors, benefiting from engineering improvements in the conjugation process and the introduction of novel linkers and payloads. With the recognition that numerous surface targets are expressed across various cancer histologies, alongside the remarkable activity of modern ADCs, this drug class has been increasingly evaluated as suitable for a histology-agnostic expansion of indication. For illustration, the anti-HER2 ADC trastuzumab deruxtecan has demonstrated compelling activity in HER2-overexpressing breast, gastric, colorectal, and lung cancer. Examples of additional novel and potentially histology-agnostic ADC targets include trophoblast cell-surface antigen 2 (Trop-2) and nectin-4, among others. In the current review article, the authors summarize the current approvals of ADCs by the US Food and Drug Administration focusing on solid tumors and discuss the challenges and opportunities posed by the multihistological expansion of ADCs.

Antibody-drug conjugates: A promising novel therapeutic approach in lung cancer

Antibody-drug conjugates (ADCs) are rapidly establishing their place and have shown promising preliminary data in lung cancer with impressive response rates and survival outcomes in previously treated patients.There are several ADCs currently in clinical trials for NSCLC and small cell lung cancer (SCLC). These ADCs often have different targets which include HER2, HER3, TROP2, CEACAM5, and MET in NSCLC and DLL3 in SCLC.Here we review the safety, and efficacy of newer ADCs in lung cancer including ado-trastuzumab emtansine, trastuzumab deruxetecan, patritomab deruxetecan, datopotamab deruxetecan, sacituzumab govitecan, SAR408701, Telisotuzumab vedotin, rovalpituzumab tesirine, lorvotuzumab mertansine, and sacituzumab govitecan.  Several novel methods are underway to improve the safety and efficacy of ADCs which include increasing the drug to antibody ratio (DAR), the potency of the payload, using more innovative payloads and replacing the antibody.

Antibody drug conjugates in non-small cell lung cancer: An emerging therapeutic approach

The current standard-of-care for the treatment of advanced non-small cell lung cancer (NSCLC) incorporates targeted therapies, immune-checkpoint inhibitors (ICI) and systemic chemotherapy. Antibody-drug conjugates (ADC) are a class of anti-cancer therapy capable of transporting cytotoxic drugs directly to tumour cells, thus harnessing the strengths of both cytotoxic chemotherapy and targeted therapy. In this review we provide a comprehensive review the design, mode of action, and mechanisms of resistance to ADCs in NSCLC. We also summarize the clinical development of several promising ADCs in early phase clinical trials for the treatment NSCLC. including ADCs against well-established targets (e.g.HER2 in breast cancer, Nectin4 in urothelial cancer), novel antigenic targets (e.g. HER3, TROP2, PTK7, CEACAM5), as well as promising combinations with agents known to be active in NSCLC such as tyrosine kinase inhibitors and ICI therapy, as a strategy to overcome mechanisms of resistance to ADC therapy.

Interstitial Lung Disease Induced by Anti-ERBB2 Antibody-Drug Conjugates: A Review

Importance

In the past decade, ERBB2 (formerly HER2)-directed antibody-drug conjugates (ADCs) have substantially changed treatment of both advanced and early-stage ERBB2-positive breast cancer. Novel conjugates are now showing activity in trials of other ERBB2-associated tumors, leading to the recent US Food and Drug Administration approval of trastuzumab deruxtecan for ERBB2-positive gastric cancer, as well as beneficial results in colorectal, lung, and bladder cancer. It is thus possible that anti-ERBB2 ADCs may become a treatment option for multiple types of tumors because many have at least some expression of ERBB2. Despite an improved overall therapeutic index, clinical observations have recently raised a concern regarding potential lung toxicity of anti-ERBB2 ADCs. Deaths related to interstitial lung disease (ILD) have been reported with variable incidence in trials testing anti-ERBB2 conjugates, warranting appropriate training of clinicians for the identification and management of this toxic effect.

Observations

Although no specific guidelines are available for the diagnosis and management of ADC-related ILD, some recommendations can be derived based on general principles adopted for drug-induced and immunotherapy-related ILD. Overall, in symptomatic ILD, the ADC should be discontinued. Reintroduction of the conjugate can be considered only in asymptomatic cases after complete resolution. Corticosteroids represent the cornerstone of ILD treatment, and dosing should be adapted according to the severity of the event. Additional treatments can be considered based on the clinical scenario.

Conclusions and Relevance

This review summarizes the current knowledge on the pathogenesis and epidemiologic characteristics of anti-ERBB2 ADC-related lung toxicity, proposing strategies for its diagnosis and treatment. Earlier diagnosis and more adequate treatment of ADC-induced ILD may improve the therapeutic index of this important class of anticancer agents, allowing for a safe expansion of anti-ERBB2 ADCs across tumor types.

Sacituzumab govitecan and trastuzumab deruxtecan: two new antibody-drug conjugates in the breast cancer treatment landscape

BACKGROUND

Two new antibody-drug conjugates (ADCs) containing a topoisomerase I inhibitor payload have recently emerged in the breast cancer (BC) treatment landscape. Sacituzumab govitecan-hziy (SG) is a first-in-class anti-trophoblast cell-surface antigen 2 ADC approved for pretreated metastatic triple-negative breast cancer (mTNBC) and trastuzumab deruxtecan (T-DXd) gained approval for human epidermal growth factor receptor-2 (HER2)-positive advanced BC (aBC). We aim to provide a contemporary review and the current clinical trial landscape of SG and T-DXd in BC.

MATERIALS AND METHODS

We conducted a literature search from Medline database through PubMed, major conference proceedings [abstracts from European Society for Medical Oncology (Breast) Congress, American Society of Clinical Oncology annual meeting, San Antonio Breast Cancer Symposium] and ClinicalTrials.gov with search terms 'sacituzumab govitecan', 'IMMU-132', 'trastuzumab deruxtecan' and 'DS-8201a' up to 21 March 2021.

RESULTS

We assessed 293 records for eligibility, of which 153 were included in this review after screening and exclusion. For SG, efficacy and safety data are available from a phase III trial in pretreated mTNBC and from a phase I/II basket study in mTNBC and hormone receptor-positive/HER2-negative aBC. Thirteen trials with pending primary analysis are ongoing with SG as single agent or in combination, of which 11 are enrolling (2/11 in the early setting). For T-DXd, efficacy/safety data are available as single agent in pretreated HER2-positive (phase Ib and phase II) and in HER2-low aBC (phase Ib), and in combination with nivolumab in HER2-low/positive aBC (phase Ib). Of 23 ongoing trials with T-DXd, 12 are open for enrollment and 3 phase III trials have completed recruitment. The distinct safety profiles of both drugs and their management are discussed.

CONCLUSION

Given their robust single-agent activity, SG and T-DXd are expected to substantially impact treatment standards, both in and far beyond the currently approved indications. Several trials are investigating new treatment settings for both drugs, including a transition to earlier lines and combinations with other anticancer treatments such as immune checkpoint inhibitors.

Antibody-Drug Conjugates for the Treatment of Breast Cancer

Metastatic breast cancer (BC) is currently an incurable disease. Besides endocrine therapy and targeted agents, chemotherapy is often used in the treatment of this disease. However, lack of tumor specificity and toxicity associated with dose exposure limit the manageability of cytotoxic agents. Antibody-drug conjugates (ADCs) are a relatively new class of anticancer drugs. By merging the selectivity of monoclonal antibodies with the cytotoxic properties of chemotherapy, they improve the therapeutic index of antineoplastic agents. Three core components characterize ADCs: the antibody, directed to a target antigen; the payload, typically a cytotoxic agent; a linker, connecting the antibody to the payload. The most studied target antigen is HER2 with some agents, such as trastuzumab deruxtecan, showing activity not only in HER2-positive, but also in HER2-low BC patients, possibly due to a bystander effect. This property to provide a cytotoxic impact also against off-target cancer cells may overcome the intratumoral heterogeneity of some target antigens. Other cancer-associated antigens represent a strategy for the development of ADCs against triple-negative BC, as shown by the recent approval of sacituzumab govitecan. In this review, we discuss the current landscape of ADC development for the treatment of BC, as well as the possible limitations of this treatment.