Datopotamab-deruxtecan plus durvalumab in early-stage breast cancer: the sequential multiple assignment randomized I-SPY2.2 phase 2 trial

Novel treatment approaches utilizing antibody-drug conjugates in breast cancer

Antibody-drug conjugates (ADCs) are rapidly changing the way we treat patients with breast cancer. Despite this progress, many unanswered questions remain regarding the sequencing of different ADCs with similar payloads, optimal combinations, drug design strategies to limit off-target toxicities, biomarkers to define antigen positivity, and the use of ADCs in the neoadjuvant and adjuvant settings. In this review, we summarize novel ADC approaches in breast cancer treatment, including potential improvements in ADC payloads, linkers, targets, and drug delivery. We also evaluate novel strategies to combine ADCs with other agents, such as targeted drugs and immune checkpoint inhibitors. To improve patient selection, the development of quantitative biomarkers is reviewed, including HER2 mRNA, immunofluorescence-based assays, mass spectrometry, liquid biopsies, digital pathology, and molecular imaging-based approaches. Lastly, we evaluate the potential to incorporate ADCs into the early-stage setting, including evaluating currently published and ongoing clinical trials. This review highlights the potential for ADCs to shift the treatment paradigm in both the advanced and early-stage settings. We further demonstrate the complexity and challenges of improving ADCs to enhance targeting of tumor vulnerabilities while limiting toxicity through rationale drug development strategies to enhance the therapeutic window, linker technology, and payload variability to continue to improve outcomes for patients with breast cancer.

TROPION-Breast05: a randomized phase III study of Dato-DXd with or without durvalumab versus chemotherapy plus pembrolizumab in patients with PD-L1-high locally recurrent inoperable or metastatic triple-negative breast cancer

Background

Standard of care (SoC) for patients with advanced triple-negative breast cancer (TNBC) whose tumors express PD-L1 (combined positive score ⩾ 10) is chemotherapy plus anti-PD-(L)1 inhibitors; however, prognosis and survival for most patients is poor. Datopotamab deruxtecan (Dato-DXd), a novel antibody-drug conjugate comprising a humanized anti-TROP2 IgG1 monoclonal antibody conjugated to a potent topoisomerase I inhibitor payload via a plasma-stable, cleavable, tetrapeptide-based linker, has shown preliminary activity as mono or combination therapy in advanced/metastatic TNBC.

Objectives

TROPION-Breast05 is an ongoing randomized, open-label, multicenter phase III study. The primary objective is to demonstrate the superiority of Dato-DXd in combination with durvalumab (an anti-PD-L1 antibody) versus SoC treatment in patients with PD-L1-high locally recurrent inoperable or metastatic TNBC.

Methods and design

Patients (⩾18 years) will be randomized 1:1 to receive Dato-DXd (6 mg/kg intravenously (IV) every 3 weeks (Q3W)) plus durvalumab (1120 mg IV Q3W) or investigator's choice of chemotherapy (ICC; paclitaxel, nab-paclitaxel, or gemcitabine plus carboplatin) plus pembrolizumab (200 mg IV Q3W). In selected countries, patients will also be randomized (1:1:1) to a third arm of Dato-DXd monotherapy. The primary study endpoint is progression-free survival (PFS) per blinded independent central review (Dato-DXd plus durvalumab arm vs ICC plus pembrolizumab arm). Overall survival is a key secondary endpoint; other secondary endpoints include PFS (investigator-assessed), objective response rate, duration of response, clinical benefit rate at Week 24 (all assessed in the Dato-DXd plus durvalumab arm vs ICC plus pembrolizumab arm), patient-reported outcomes, and safety.

Ethics

The study is approved by independent ethics committees or institutional review boards at each study site. All patients will provide written informed consent.

Discussion

TROPION-Breast05 will assess the potential role of Dato-DXd with or without durvalumab in patients with PD-L1-high advanced or metastatic TNBC. The findings of this trial could lead to a new treatment option for these patients.

Trial registration

ClinicalTrials.gov identifier: NCT06103864 (Date of registration: 27 October 2023).

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.

Impact of postprogression therapies on overall survival: Recommendations from the 2023 kidney cancer association think tank meeting

Modern advances in systemic and localized therapies for patients with renal cell carcinoma (RCC) have significantly improved patients' outcomes. If disease progression occurs after initial treatment, clinicians often have multiple options for a first salvage therapy. Because salvage and initial treatments both may affect overall survival time, and they may interact in unanticipated ways, there is a growing need to determine sequences of initial therapy and first salvage therapy that maximize overall survival while maintaining quality of life. The complexity of this problem grows if a second salvage therapy must be chosen for patients with treatment-resistant disease or a second progression occurs following first salvage. On November 9, 2023, a think tank was convened during the International Kidney Cancer Symposium (IKCS) North America to discuss challenges in accounting for postprogression therapies when estimating overall survival (OS) time based on randomized controlled trial (RCT) data. The present manuscript summarizes the topics discussed, with the aim to encourage adoption of statistical methods that account for salvage therapy effects to obtain scientifically valid OS estimation. We highlight limitations of traditional methods for estimating OS that account for initial treatments while ignoring salvage therapy effects and discuss advantages of applying more sophisticated statistical methods for estimation and trial design. These include identifying multistage treatment strategies, correcting for confounding due to salvage therapy effects, and conducting Sequentially Multiple Assignment Randomized Trials (SMARTs) to obtain unbiased comparisons between multistage strategies. We emphasize the critical role of patient input in trial design, and the potential for information technology (IT) advances to support complex trial designs and real-time data analyses. By addressing these challenges, future RCTs can better inform clinical decision-making and improve patient outcomes in RCC.

TROPION-Breast04: a randomized phase III study of neoadjuvant datopotamab deruxtecan (Dato-DXd) plus durvalumab followed by adjuvant durvalumab versus standard of care in patients with treatment-naïve early-stage triple negative or HR-low/HER2- breast cancer

Background

Despite treatment advances for patients with early-stage triple-negative breast cancer (TNBC) and hormone receptor (HR)-low/human epidermal growth factor receptor 2-negative (HER2-) breast cancer, treatments that improve clinical outcomes while mitigating toxicity are needed. Datopotamab deruxtecan (Dato-DXd), a TROP2-directed antibody-drug conjugate consisting of a humanized IgG1 monoclonal antibody attached via a plasma-stable cleavable linker to a topoisomerase-I inhibitor payload, has shown efficacy alone or in combination with durvalumab, a selective, high-affinity anti-programmed cell death ligand 1 antibody, in early-phase clinical studies.

Objectives

The primary objective of TROPION-Breast04 is to evaluate the efficacy and safety of neoadjuvant Dato-DXd plus durvalumab followed by adjuvant durvalumab with or without chemotherapy versus standard of care in patients with previously untreated early-stage TNBC or HR-low/HER2- breast cancer.

Design

This is an ongoing, international, phase III, open-label, randomized controlled study.

Methods and analysis

Approximately 1728 patients (aged ⩾18 years) will be randomized 1:1 to eight cycles of neoadjuvant Dato-DXd (6 mg/kg intravenously (IV) every 3 weeks (Q3W)) plus durvalumab (1120 mg IV Q3W) followed by nine cycles of adjuvant durvalumab (1120 mg IV Q3W) with or without chemotherapy versus eight cycles of pembrolizumab (200 mg IV Q3W) plus chemotherapy followed by nine cycles of adjuvant pembrolizumab (200 mg IV Q3W) with or without chemotherapy. Dual primary endpoints are pathological complete response by blinded central review and event-free survival by investigator assessment. Secondary endpoints include overall survival (key), distant disease-free survival, patient-reported outcomes, and safety.

Ethics

The study is approved by independent ethics committees and/or institutional review boards at each study site. All patients will provide written informed consent.

Discussion

This study will evaluate the potential use of neoadjuvant Dato-DXd plus durvalumab followed by adjuvant durvalumab with or without chemotherapy versus standard of care in patients with previously untreated early-stage TNBC or HR-low/HER2- breast cancer. The findings of this trial could lead to promising treatment options for these patients.

Trial registration

ClinicalTrials.gov identifier: NCT06112379.

Estrogen Signaling in Early-Stage Breast Cancer: Impact on Neoadjuvant Chemotherapy and Immunotherapy

Neoadjuvant chemoimmunotherapy (NACIT) has been shown to improve pathologic complete response (pCR) rates and survival outcomes in stage II-III triple-negative breast cancer (TNBC). Promising pCR rate improvements have also been documented for selected patients with estrogen receptor-positive (ER+) human epidermal growth factor receptor 2-negative (HER2-) breast cancer (BC). However, one size does not fit all and predicting which patients will benefit from NACIT remains challenging. Accurate predictions would be useful to minimize immune-related toxicity, which can be severe, irreversible, and potentially impact fertility and quality of life, and to identify patients in need of alternative treatments. This review aims to capitalize on the existing translational and clinical evidence on predictors of treatment response in patients with early-stage BC treated with neoadjuvant chemotherapy (NACT) and NACIT. It summarizes evidence suggesting that NACT/NACIT effectiveness may correlate with pre-treatment tumor characteristics, including mutational profiles, ER expression and signaling, immune cell presence and spatial organization, specific gene signatures, and the levels of proliferating versus quiescent cancer cells. However, the predominantly qualitative and descriptive nature of many studies highlights the challenges in integrating various potential response determinants into a validated, comprehensive, and multimodal predictive model. The potential of novel multi-modal approaches, such as those based on artificial intelligence, to overcome current challenges remains unclear, as these tools are not free from bias and shortcut learning. Despite these limitations, the rapid evolution of these technologies, coupled with further efforts in basic and translational research, holds promise for improving treatment outcome predictions in early HER2- BC.

A roadmap to reduce the incidence and mortality of breast cancer by rethinking our approach to women's health

Despite progress, breast cancer remains the most feared disease among women. In the USA alone, the incidence is now almost 300,000 new cancers per year, a rate that has nearly doubled in the last 30 years. Most women survive, but over 40,000 women a year still die of their disease [99]. It is the most diagnosed cancer among women and the second leading cause of cancer death. Important disparities exist in breast cancer outcomes among African American women, where women die of breast cancer at higher rates, are diagnosed younger, and at a more advanced stage. We are proposing a radical shift in our thinking about breast cancer prevention with an aspiration to dramatically lower breast cancer incidence. Most breast cancers are driven by steroid hormones. Throughout the life course, women are offered an array of hormonal treatments for menstrual cycle control, family planning, in vitro fertilization, postpartum weaning, and menopausal symptom management. There are mixed data on the extent to which each of these may contribute to increased or decreased risk for breast cancer. These endocrine manipulations could represent a great opportunity to potentially reduce breast cancer incidence and improve quality of life for survivors. To date, they have not been designed to explicitly reduce breast cancer risk. A new holistic approach will require scientists, drug developers, breast oncologists, obstetricians, gynecologists, endocrinologists, radiologists, and family medicine/internists to work together toward the common goal of reducing breast cancer risk while addressing other critical issues in women's health.

Datopotamab-deruxtecan in early-stage breast cancer: the sequential multiple assignment randomized I-SPY2.2 phase 2 trial

Among the goals of patient-centric care are the advancement of effective personalized treatment, while minimizing toxicity. The phase 2 I-SPY2.2 trial uses a neoadjuvant sequential therapy approach in breast cancer to further these goals, testing promising new agents while optimizing individual outcomes. Here we tested datopotamab-deruxtecan (Dato-DXd) in the I-SPY2.2 trial for patients with high-risk stage 2/3 breast cancer. I-SPY2.2 uses a sequential multiple assignment randomization trial design that includes three sequential blocks of biologically targeted neoadjuvant treatment: the experimental agent(s) (block A), a taxane-based regimen tailored to the tumor subtype (block B) and doxorubicin-cyclophosphamide (block C). Patients are randomized into arms consisting of different investigational block A treatments. Algorithms based on magnetic resonance imaging and core biopsy guide treatment redirection after each block, including the option of early surgical resection in patients predicted to have a high likelihood of pathological complete response, the primary endpoint. There are two primary efficacy analyses: after block A and across all blocks for the six prespecified breast cancer subtypes (defined by clinical hormone receptor/human epidermal growth factor receptor 2 (HER2) status and/or the response-predictive subtypes). We report results of 103 patients treated with Dato-DXd. While Dato-DXd did not meet the prespecified threshold for success (graduation) after block A in any subtype, the treatment strategy across all blocks graduated in the hormone receptor-negative HER2-Immune-DNA repair deficiency- subtype with an estimated pathological complete response rate of 41%. No new toxicities were observed, with stomatitis and ocular events occurring at low grades. Dato-DXd was particularly active in the hormone receptor-negative/HER2-Immune-DNA repair deficiency- signature, warranting further investigation, and was safe in other subtypes in patients who followed the treatment strategy. ClinicalTrials.gov registration: NCT01042379 .