Synthesis and evaluation of antibody-drug conjugates with high drug-to-antibody ratio using dimaleimide-DM1 as a linker- payload.

The notable characteristics of recently emerged Antibody-Drug Conjugates (ADCs) encompass the targeting of Human Epidermal growth factor Receptor 2 (HER2) through monoclonal antibodies (mAbs) and a high ratio of drug to antibody (DAR). The achievements of Kadcyla® (T-DM1) and Enhertu® (T-Dxd) have demonstrated that HER2-targeting antibodies, such as trastuzumab, have shown to be competitive in terms of efficacy and price for development. Furthermore, with the arrival of T-Dxd and Trodelvy®, high-DAR (7-8) ADCs, which differ from the moderate DAR (3-4) ADCs that were formerly regarded as conventional, are being acknowledged for their worth. Following this trend of drug development, we endeavored to develop a high-DAR ADC using a straightforward approach involving the utilization of DM1, a highly potent substance, in combination with the widely recognized trastuzumab. To achieve a high DAR, DM1 was conjugated to reduced cysteine through the simple design and synthesis of various dimaleimide linkers with differing lengths. Using LC and MS analysis, we have demonstrated that our synthesis methodology is uncomplicated and efficacious, yielding trastuzumab-based ADCs that exhibit a remarkable degree of uniformity. These ADCs have been experimentally substantiated to exert an inhibitory effect on cancer cells in vitro, thus affirming their value as noteworthy additions to the realm of ADCs.

Systematic literature review of real-world evidence for treatments in HR+/HER2- second-line LABC/mBC after first-line treatment with CDK4/6i.

BACKGROUND: Cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) combined with endocrine therapy (ET) are currently recommended by the National Comprehensive Cancer Network (NCCN) guidelines and the European Society for Medical Oncology (ESMO) guidelines as the first-line (1 L) treatment for patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative, locally advanced/metastatic breast cancer (HR+/HER2- LABC/mBC). Although there are many treatment options, there is no clear standard of care for patients following 1 L CDK4/6i. Understanding the real-world effectiveness of subsequent therapies may help to identify an unmet need in this patient population. This systematic literature review qualitatively synthesized effectiveness and safety outcomes for treatments received in the real-world setting after 1 L CDK4/6i therapy in patients with HR+/ HER2- LABC/mBC. METHODS: MEDLINE®, Embase, and Cochrane were searched using the Ovid® platform for real-world evidence studies published between 2015 and 2022. Grey literature was searched to identify relevant conference abstracts published from 2019 to 2022. The review was conducted in accordance with PRISMA guidelines (PROSPERO registration: CRD42023383914). Data were qualitatively synthesized and weighted average median real-world progression-free survival (rwPFS) was calculated for NCCN/ESMO-recommended post-1 L CDK4/6i treatment regimens. RESULTS: Twenty records (9 full-text articles and 11 conference abstracts) encompassing 18 unique studies met the eligibility criteria and reported outcomes for second-line (2 L) treatments after 1 L CDK4/6i; no studies reported disaggregated outcomes in the third-line setting or beyond. Sixteen studies included NCCN/ESMO guideline-recommended treatments with the majority evaluating endocrine-based therapy; five studies on single-agent ET, six studies on mammalian target of rapamycin inhibitors (mTORi) ± ET, and three studies with a mix of ET and/or mTORi. Chemotherapy outcomes were reported in 11 studies. The most assessed outcome was median rwPFS; the weighted average median rwPFS was calculated as 3.9 months (3.3-6.0 months) for single-agent ET, 3.6 months (2.5-4.9 months) for mTORi ± ET, 3.7 months for a mix of ET and/or mTORi (3.0-4.0 months), and 6.1 months (3.7-9.7 months) for chemotherapy. Very few studies reported other effectiveness outcomes and only two studies reported safety outcomes. Most studies had heterogeneity in patient- and disease-related characteristics. CONCLUSIONS: The real-world effectiveness of current 2 L treatments post-1 L CDK4/6i are suboptimal, highlighting an unmet need for this patient population.

Discovery of Potent and Selective Covalent Inhibitors of HER2WT and HER2YVMA.

HER2 overexpression and amplification have been identified as oncogenic drivers, and the development of therapies to treat tumors harboring these markers has received considerable attention. Activation of HER2 signaling and subsequent cell growth can also be induced by HER2 mutations, including the common YVMA insertion in exon 20 within the kinase domain. Enhertu is currently the only approved treatment for HER2 mutant tumors in NSCLC. TKIs tested in this space have suffered from off-target activity, primarily due to EGFRWT inhibition or attenuated activity against HER2 mutants. The goal of this work was to identify a TKI that would provide robust inhibition of oncogenic HER2WT and HER2 mutants while sparing EGFRWT activity. Herein, we describe the development of a potent, covalent inhibitor of HER2WT and the YVMA insertion mutant while providing oral bioavailability and avoiding the inhibition of EGFRWT.

State of the art and upcoming trends in HER2-directed therapies in gastrointestinal malignancies.

PURPOSE OF REVIEW: This review critically evaluates the evolution and current status of human epidermal growth factor receptor 2 (HER2)-directed therapies in upper gastrointestinal (GI) malignancies, a timely and relevant inquiry given the dynamic shifts in therapeutic strategies over the past decade. Initial enthusiasm following the Trastuzumab for Gastric Cancer (ToGA) study's demonstration of trastuzumab's efficacy, however, encountered hurdles due to subsequent trials showing limited progress, underscoring the necessity for a reevaluation of therapeutic approaches and the exploration of novel agents. RECENT FINDINGS: The review highlights significant breakthroughs in the form of immune checkpoint inhibitors and innovative therapeutic technologies, which have redefined treatment paradigms and shown promising efficacy in HER2-positive cases. Emerging treatments such as trastuzumab deruxtecan (T-DXd), zanidatamab and evorpacept further illustrate the ongoing efforts to leverage unique mechanisms of action for improved HER2-positive antitumor activity. SUMMARY: The advancements in HER2-directed therapies underscore a pivotal era in the management of upper GI malignancies. These developments not only reflect the profound impact of integrating novel therapeutic combinations but also highlight the critical role of ongoing research in overcoming resistance mechanisms and tailoring treatment to individual disease profiles.

Development of a reliable cell-based reporter gene assay to measure the bioactivity of anti-HER2 therapeutic antibodies.

Human epidermal growth factor receptor 2 (HER2) is a key player in the pathogenesis and progression of breast cancer and is currently a primary target for breast cancer immunotherapy. Bioactivity determination is necessary to guarantee the safety and efficacy of therapeutic antibodies targeting HER2. Nevertheless, currently available bioassays for measuring the bioactivity of anti-HER2 mAbs are either not representative or have high variability. Here, we established a reliable reporter gene assay (RGA) based on T47D-SRE-Luc cell line that expresses endogenous HER2 and luciferase controlled by serum response element (SRE) to measure the bioactivity of anti-HER2 antibodies. Neuregulin-1 (NRG-1) can lead to the heterodimerization of HER2 on the cell membrane and induce the expression of downstream SRE-controlled luciferase, while pertuzumab can dose-dependently reverse the reaction, resulting in a good dose-response curve reflecting the activity of the antibody. After optimizing the relevant assay parameters, the established RGA was fully validated based on ICH-Q2 (R1), which demonstrated that the method had excellent specificity, accuracy, precision, linearity, and stability. In summary, this robust and innovative bioactivity determination assay can be applied in the development and screening, release control, biosimilar assessment and stability studies of anti-HER2 mAbs.

Implementation of antibody-drug conjugates in HER2-positive solid cancers: Recent advances and future directions.

In recent decades, there has been a surge in the approval of monoclonal antibodies for treating a wide range of hematological and solid malignancies. These antibodies exhibit exceptional precision in targeting the surface antigens of tumors, heralding a groundbreaking approach to cancer therapy. Nevertheless, monoclonal antibodies alone do not show sufficient lethality against cancerous cells compared to chemotherapy. Consequently, a new class of anti-tumor medications, known as antibody-drug conjugates (ADCs), has been developed to bridge the divide between monoclonal antibodies and cytotoxic drugs, enhancing their therapeutic potential. ADCs are chemically synthesized by binding tumor-targeting monoclonal antibodies with cytotoxic payloads through linkers that are susceptible to cleavage by intracellular proteases. They combined the accurate targeting of monoclonal antibodies with the potent efficacy of cytotoxic chemotherapy drugs while circumventing systemic toxicity and boasting superior lethality over standalone targeted drugs. The human epidermal growth factor receptor (HER) family, which encompasses HER1 (also known as EGFR), HER2, HER3, and HER4, plays a key role in regulating cellular proliferation, survival, differentiation, and migration. HER2 overexpression in various tumors is one of the most frequently targeted antigens for ADC therapy in HER2-positive cancers. HER2-directed ADCs have emerged as highly promising treatment modalities for patients with HER2-positive cancers. This review focuses on three approved anti-HER2 ADCs (T-DM1, DS-8201a, and RC48) and reviews ongoing clinical trials and failed trials based on anti-HER2 ADCs. Finally, we address the notable challenges linked to ADC development and underscore potential future avenues for tackling these hurdles.

Trastuzumab deruxtecan in breast cancer.

Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate (ADC) consisting of a humanised, anti-human epidermal growth factor receptor 2 (HER2) monoclonal antibody covalently linked to a topoisomerase I inhibitor cytotoxic payload (DXd). The high drug-to-antibody ratio (8:1) ensures a high DXd concentration is delivered to target tumour cells, following internalisation of T-DXd and subsequent cleavage of its tetrapeptide-based linker. DXd's membrane-permeable nature enables it to cross cell membranes and potentially exert antitumour activity on surrounding tumour cells regardless of HER2 expression. T-DXd's unique mechanism of action is reflected in its efficacy in clinical trials in patients with HER2-positive advanced breast cancer (in heavily pretreated populations and in those previously treated with a taxane and trastuzumab), as well as HER2-low metastatic breast cancer. Thus, ADCs such as T-DXd have the potential to change the treatment paradigm of targeting HER2 in metastatic breast cancer, including eventually within the adjuvant/neoadjuvant setting.

Antibody-dye Conjugates Targeting EGFR and HER2 for the Photoimmunotherapy of Bladder Cancer.

BACKGROUND/AIM: Although there are curative treatment options for non-muscle-invasive bladder cancer, the recurrence of this tumor is high. Therefore, novel targeted therapies are needed for the complete removal of bladder cancer cells in stages of localized disease, in order to avoid local recurrence, to spare bladder cancer patients from stressful and expensive treatment procedures and to increase their quality of life and life expectancy. This study tested a new approach for the photoimmunotherapy (PIT) of bladder cancer. MATERIALS AND METHODS: We generated a cysteine modified recombinant version of the antibody cetuximab targeting the epidermal growth factor receptor (EGFR) on the surface of bladder cancer cells. Then, we coupled the novel photoactivatable phthalocyanine dye WB692-CB1 via a maleimide linker to the free cysteines of the antibody. PIT was performed by incubating bladder cancer cells with the antibody dye conjugate followed by irradiation with visible red light. RESULTS: The conjugate was able to induce specific cytotoxicity in EGFR-positive bladder cancer cells in a light dose-dependent manner. Enhanced cytotoxicity in RT112 bladder cancer cells was evoked by addition of a second antibody dye conjugate targeting HER2 or by repeated cycles of PIT. CONCLUSION: Our new antibody dye conjugate targeting EGFR-expressing bladder cancer cells is a promising candidate for the future PIT of bladder cancer patients.

The HSP90 inhibitor HVH-2930 exhibits potent efficacy against trastuzumab-resistant HER2-positive breast cancer.

Rationale: Resistance to targeted therapies like trastuzumab remains a critical challenge for HER2-positive breast cancer patients. Despite the progress of several N-terminal HSP90 inhibitors in clinical trials, none have achieved approval for clinical use, primarily due to issues such as induction of the heat shock response (HSR), off-target effects, and unfavorable toxicity profiles. We sought to examine the effects of HVH-2930, a novel C-terminal HSP90 inhibitor, in overcoming trastuzumab resistance. Methods: The effect of HVH-2930 on trastuzumab-sensitive and -resistant cell lines in vitro was evaluated in terms of cell viability, expression of HSP90 client proteins, and impact on cancer stem cells. An in vivo model with trastuzumab-resistant JIMT-1 cells was used to examine the efficacy and toxicity of HVH-2930. Results: HVH-2930 was rationally designed to fit into the ATP-binding pocket interface cavity of the hHSP90 homodimer in the C-terminal domain of HSP90, stabilizing its open conformation and hindering ATP binding. HVH-2930 induces apoptosis without inducing the HSR but by specifically suppressing the HER2 signaling pathway. This occurs with the downregulation of HER2/p95HER2 and disruption of HER2 family member heterodimerization. Attenuation of cancer stem cell (CSC)-like properties was associated with the downregulation of stemness factors such as ALDH1, CD44, Nanog and Oct4. Furthermore, HVH-2930 administration inhibited angiogenesis and tumor growth in trastuzumab-resistant xenograft mice. A synergistic effect was observed when combining HVH-2930 and paclitaxel in JIMT-1 xenografts. Conclusion: Our findings highlight the potent efficacy of HVH-2930 in overcoming trastuzumab resistance in HER2-positive breast cancer. Further investigation is warranted to fully establish its therapeutic potential.

Absolute lymphocyte count and neutrophil-to-lymphocyte ratio as predictors of CDK 4/6 inhibitor efficacy in advanced breast cancer.

Cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) are the standard agents for treating patients with estrogen receptor-positive and human epidermal growth factor receptor 2-negative advanced breast cancer (ER + HER2 - ABC). However, markers predicting the outcomes of CDK4/6i treatment have yet to be identified. This study was a single-center retrospective cohort study. We retrospectively evaluated 101 patients with ER + HER2 - ABC receiving CDK4/6i in combination with endocrine therapy at Fukuyama City Hospital between November 2017 and July 2021. We investigated the clinical outcomes and the safety of CDK4/6i treatment, and the absolute lymphocyte count (ALC) and neutrophil-to-lymphocyte ratio (NLR) as predictive markers for CDK4/6i. We defined the cut-off values as 1000/µL for ALC and 3 for NLR, and divided into "low" and "high" groups, respectively. We evaluated 43 and 58 patients who received abemaciclib and palbociclib, respectively. Patients with high ALC and low NLR had significantly longer overall survival than those with low ALC and high NLR (high vs. low; ALC: HR 0.29; 95% CI 0.12-0.70; NLR: HR 2.94; 95% CI 1.21-7.13). There was no significant difference in efficacy between abemaciclib and palbociclib and both had good safety profiles. We demonstrated that ALC and NLR might predict the outcomes of CDK4/6i treatment in patients with ER + HER2 - ABC.

Preclinical Evaluation of HER2-Targeting DARPin G3: Impact of Albumin-Binding Domain (ABD) Fusion.

Designed ankyrin repeat protein (DARPin) G3 is an engineered scaffold protein. This small (14.5 kDa) targeting protein binds with high affinity to human epidermal growth factor receptor 2 (HER2). HER2 is overexpressed in several cancers. The use of the DARPin G3 for radionuclide therapy is complicated by its high renal reabsorption after clearance via the glomeruli. We tested the hypothesis that a fusion of the DARPin G3 with an albumin-binding domain (ABD) would prevent rapid renal excretion and high renal reabsorption resulting in better tumour targeting. Two fusion proteins were produced, one with the ABD at the C-terminus (G3-ABD) and another at the N-terminus (ABD-G3). Both variants were labelled with 177Lu. The binding properties of the novel constructs were evaluated in vitro and their biodistribution was compared in mice with implanted human HER2-expressing tumours. Fusion with the ABD increased the retention time of both constructs in blood compared with the non-ABD-fused control. The effect of fusion with the ABD depended strongly on the order of the domains in the constructs, resulting in appreciably better targeting properties of [177Lu]Lu-G3-ABD. Our data suggest that the order of domains is critical for the design of targeting constructs based on scaffold proteins.

Discovery of novel HER2 targeting peptide-camptothecin conjugates with effective suppression for selective cancer treatment.

Due to the strong selectivity and permeability of tumor tissue, anti-cancer peptide-drug conjugates (PDCs) can accumulate high concentration of toxic payloads at the target, effectively killing tumor cells. This approach holds great promise for tumor-targeted treatment. In our previous study, we identified the optimal peptide P1 (NPNWGRSWYNQRFK) targeting HER2 from pertuzumab, a monoclonal antibody that blocks the HER2 signaling pathway. Here, a series of PDCs were constructed through connecting P1 and CPT with different linkers. Among these, Z8 emerged as the optimal compound, demonstrating good antitumor activity and targeting ability in biological activity tests. Z8 exhibited IC50 values of 1.04 ± 0.24 µM and 1.91 ± 0.71 µM against HER2-positive SK-BR-3 and NCI-N87 cells, respectively. Moreover, superior antitumor activity and higher biosafety of Z8 were observed compared to the positive control CPT in vivo, suggesting a novel idea for the construction of PDCs.

[Administration of anti-HER2 and satisfaction of patients treated for breast cancer]. / Administration des anti-HER2 et satisfaction des patients avec un cancer du sein.

INTRODUCTION: Quality of life (QoL) and patient satisfaction are major concerns in oncology. METHODS: The aim of this prospective observational study was to evaluate these parameters according to the mode of administration of anti-HER2 (subcutaneous [SC] versus intravenous [IV]), the place of administration (Home Hospitalization or HOD versus hospital) for patients supervised by an advanced practice nurse (APN). RESULTS: Between January 2022 and June 2023, 32 patients were included. They were statistically more satisfied with subcutaneous management (P=0.0004), a result explained by the speed of administration (43.5%), comfort during administration (26%) even though some expressed pain on injection and felt less anxiety (26%). Management by the APN seems more appropriate when anti-HER2 drugs were administered in HOD. In HOD, patients perceived an overall improvement in their quality of life, appetite and cognitive abilities, with a reduction in fatigue, pain and depression (P<0.05). However, the rate of outsourcing to HOD remained too low (30.4%), as 56.3% of patients would have liked to be cared for in HOD if they had had the opportunity. CONCLUSION: SC administration of anti-HER2 under the supervision of an APN has advantages for the patient, resulting in greatest satisfaction and improved patient QOL, preferably in HOD.

Targeted dual degradation of HER2 and EGFR obliterates oncogenic signaling, overcomes therapy resistance, and inhibits metastatic lesions in HER2-positive breast cancer models.

AIMS: Human epidermal growth factor receptor 2 (HER2) is an oncogenic receptor tyrosine kinase amplified in approximately 20% of breast cancer (BC). HER2-targeted therapies are the linchpin of treating HER2-positive BC. However, drug resistance is common, and the main resistance mechanism is unknown. We tested the hypothesis that drug resistance results mainly from inadequate or lack of inhibition of HER2 and its family member epidermal growth factor receptor (EGFR). METHODS: We used clinically relevant cell and tumor models to assess the impact of targeted degradation of HER2 and EGFR on trastuzumab resistance. Trastuzumab is the most common clinically used HER2 inhibitor. Targeted degradation of HER2 and EGFR was achieved using recombinant human protein PEPDG278D, which binds to the extracellular domains of the receptors. siRNA knockdown was used to assess the relative importance of EGFR and HER2 in trastuzumab resistance. RESULTS: Both HER2 and EGFR are overexpressed in all trastuzumab-resistant HER2-positive BC cell and tumor models and that all trastuzumab-resistant models are highly vulnerable to targeted degradation of HER2 and EGFR. Degradation of HER2 and EGFR induced by PEPDG278D causes extensive inhibition of oncogenic signaling in trastuzumab-resistant HER2-positive BC cells. This is accompanied by strong growth inhibition of cultured cells, orthotopic patient-derived xenografts, and metastatic lesions in the brain and lung of trastuzumab-resistant HER2-positive BC. siRNA knockdown indicates that eliminating both HER2 and EGFR is necessary to maximize therapeutic outcome. CONCLUSIONS: This study unravels the therapeutic vulnerability of trastuzumab-resistant HER2-positive BC and shows that an agent that targets the degradation of both HER2 and EGFR is highly effective in overcoming drug resistance in this disease. The findings provide new insights and innovations for advancing treatment of drug-resistant HER2-positive breast cancer that remains an unmet problem.

Targeted Agents in Esophagogastric Cancer Beyond Human Epidermal Growth Factor Receptor-2.

Gastroesophageal cancers are highly diverse tumors in terms of their anatomic and molecular characteristics, making drug development challenging. Recent advancements in understanding the molecular profiles of these cancers have led to the identification of several new biomarkers. Ongoing clinical trials are investigating new targeted agents with promising results. CLDN18.2 has emerged as a biomarker with established activity of associated targeted therapies. Other targeted agents, such as bemarituzumab and DKN-01, are under active investigation. As new agents are incorporated into the treatment continuum, the questions of biomarker overlap, tumor heterogeneity, and toxicity management will need to be addressed.

Advances in Human Epidermal Growth Factor Receptor 2-Targeted Therapy in Upper Gastrointestinal Cancers.

The Trastuzumab for Gastric Cancer (ToGA) trial marked a pivotal moment in the adoption of trastuzumab for treating advanced human epidermal growth factor receptor 2 (HER2)-positive esophagogastric (EG) cancer. The KEYNOTE-811 trial brought to light the synergistic effect of immune modulation and HER2 targeting. Additionally, the emergence of trastuzumab deruxtecan (T-DXd) highlighted the potential of new pharmaceutical technologies to extend response, particularly for patients who have advanced beyond initial HER2-targeted therapies. This review aims to navigate through both the successes and challenges encountered historically, as well as promising current trials on innovative and transformative therapeutic strategies, including promising first-in-class and novel first-in-human agents.

HER2-Positive Metastatic Colorectal Cancer.

OPINION STATEMENT: Targeted treatment strategies are available for human epidermal growth factor receptor 2 (HER2)-positive (amplified and/or overexpressed) metastatic colorectal cancer (mCRC), and HER2 testing is indicated in patients with mCRC. At present, standard of care first-line treatment for those with HER2-positive mCRC remains chemotherapy in combination with epidermal growth factor receptor (EGFR) inhibitors or bevacizumab, depending on RAS/BRAF mutational status and tumor sidedness. HER2-targeted agents should be considered for those with RAS/BRAF wild-type disease in subsequent-line treatment and in first-line treatment for patients not appropriate for intensive therapy. While the choice of anti-HER2 therapy is empiric given lack of head-to-head comparisons, the combination of trastuzumab plus tucatinib has received FDA accelerated approval for use in this setting and is generally the authors' preference. Trastuzumab plus lapatinib, trastuzumab plus pertuzumab, and trastuzumab deruxtecan (T-DXd) also have evidence of efficacy in this setting. As T-DXd has demonstrated activity following treatment with other HER2-targeted regimens and carries an increased risk of high-grade toxicities, the authors favor reserving it for use after progression on prior anti-HER2 therapy. HER2-targeted therapies that inhibit signal transduction appear to have limited activity in those with RAS mutations, including trastuzumab-containing regimens. However, the antibody drug conjugate T-DXd has some data showing efficacy in this setting, and the authors would consider T-DXd in subsequent-line therapy for HER2-positive, RAS-mutated mCRC. Several areas of uncertainty remain regarding how to best utilize HER2-targeted therapies in mCRC. These include the optimal sequence of anti-HER2 therapies with chemotherapy and anti-EGFR therapies, the optimal combination partners for anti-HER2 therapies, and the incorporation of predictive biomarkers to guide use of anti-HER2 therapies. Results of ongoing studies may thus alter the treatment paradigm above in the coming years.

The phase I/II eNRGy trial: Zenocutuzumab in patients with cancers harboring NRG1 gene fusions.

Neuregulin 1 (NRG1) fusions are oncogenic drivers that have been detected in non-small-cell lung cancer (NSCLC), pancreatic ductal adenocarcinoma (PDAC) and other solid tumors. NRG1 fusions are rare, occurring in less than 1% of solid tumors. Patients with NRG1 fusion positive (NRG1+) cancer have limited therapeutic options. Zenocutuzumab is a novel, bispecific IgG1 antibody that targets both HER2 and HER3 proteins and inhibits NRG1 binding through a 'Dock & Block®' mechanism of action. Here, we describe the rationale and design of the phase II component of the eNRGy trial, part of the overall, open-label phase I/II, multicenter trial exploring the safety, tolerability, pharmacokinetics, pharmacodynamics, immunogenicity and antitumor activity of zenocutuzumab in patients with NRG1+ NSCLC, PDAC or other solid tumors.

eNRGy: a clinical trial of zenocutuzumab for cancer caused by NRG1 gene fusionsNRG1 gene fusions are rare mutations that cause cancer cells to grow. These fusions are found in many different types of cancer. Tumors with NRG1 gene fusions do not respond well to standard treatment options. Zenocutuzumab, or Zeno, is a treatment that is being tested to see if it can stop cancer that is growing because of NRG1 gene fusions. Here, we describe the reasoning for and design of an ongoing clinical trial (eNRGy) designed to study the efficacy (how well it works) and safety of Zeno in patients with cancer that has NRG1 gene fusions. The eNRGy trial is recruiting patients with cancer that has NRG1 gene fusions, including non-small-cell lung cancer, pancreatic cancer and others. Patients who join this trial will receive Zeno once every 2 weeks until their cancer grows. The main goal (primary end point) of this trial is to determine the percentage of patients whose tumors decrease in size by 30% or more. The eNRGy trial is currently enrolling patients. For more information, refer to ClinicalTrials.gov (Identifier: NCT02912949), visit https://nrg1.com/, or call 1-833-NRG-1234.

Quantitative systems pharmacology modeling of HER2-positive metastatic breast cancer for translational efficacy evaluation and combination assessment across therapeutic modalities.

HER2-positive (HER2+) metastatic breast cancer (mBC) is highly aggressive and a major threat to human health. Despite the significant improvement in patients' prognosis given the drug development efforts during the past several decades, many clinical questions still remain to be addressed such as efficacy when combining different therapeutic modalities, best treatment sequences, interindividual variability as well as resistance and potential coping strategies. To better answer these questions, we developed a mechanistic quantitative systems pharmacology model of the pathophysiology of HER2+ mBC that was extensively calibrated and validated against multiscale data to quantitatively predict and characterize the signal transduction and preclinical tumor growth kinetics under different therapeutic interventions. Focusing on the second-line treatment for HER2+ mBC, e.g., antibody-drug conjugates (ADC), small molecule inhibitors/TKI and chemotherapy, the model accurately predicted the efficacy of various drug combinations and dosing regimens at the in vitro and in vivo levels. Sensitivity analyses and subsequent heterogeneous phenotype simulations revealed important insights into the design of new drug combinations to effectively overcome various resistance scenarios in HER2+ mBC treatments. In addition, the model predicted a better efficacy of the new TKI plus ADC combination which can potentially reduce drug dosage and toxicity, while it also shed light on the optimal treatment ordering of ADC versus TKI plus capecitabine regimens, and these findings were validated by new in vivo experiments. Our model is the first that mechanistically integrates multiple key drug modalities in HER2+ mBC research and it can serve as a high-throughput computational platform to guide future model-informed drug development and clinical translation.