Cyclobenzaprine hydrochloride (Flexeril) is a muscle relaxant primarily used to relieve muscle pain and spasms. However, its potential anti-cancer role remains largely unexplored. This study aims to investigate the inhibitory effect of Flexeril on esophageal squamous cell carcinoma (ESCC) and to uncover the molecular mechanisms through which it affects the proliferation and metastasis of ESCC.

A compound library approved by the FDA was employed to screen drugs with inhibitory effects on ESCC. Cell viability was assessed using the Cell Counting Kit-8 (CCK-8) assay, and Plate colony formation was analyzed to evaluate the proliferative ability of ESCC cell lines (KYSE150 and Eca109) after treatment with Flexeril. Migratory ability was examined through Transwell and Scratch assays. Proteomics was performed to identify proteins regulated by Flexeril in KYSE150 and Eca109 cells. RT-PCR and Western blot were used to detect changes in related genes at the mRNA and protein levels after treatment with Flexeril. Drug affinity responsive target stability (DARTS) assay and cellular thermal shift assay (CETSA) were employed to identify the binding of Flexeril and JAK1 protein. Additionally, the comet assay was conducted to assess the DNA damage response in ESCC cells following WDHD1 knockdown or Flexeril exposure. Finally, tumor‑bearing nude mice model were constructed to evaluate the in vivo anticancer effects of Flexeril on ESCC.

Flexeril significantly inhibited the proliferation and migration of ESCC cells in a time- and dose-dependent manner. Proteomics analysis identified WDHD1 as a downstream target of Flexeril exposure, and knockdown of WDHD1 mimicked the effects of Flexeril on proliferation and migration of ESCC. Conversely, overexpression of WDHD1 attenuated the inhibitory effects of Flexeril on ESCC. Mechanistically, the JAK1-STAT3 signaling pathway, but not the JAK2-STAT3 or PI3K-Akt-mTOR pathways, was involved in regulating WDHD1 expression in ESCC cells following Flexeril treatment. Overexpression of STAT3 or WDHD1 mitigated the inhibitory effects of Flexeril on ESCC proliferation and migration. Moreover, both Flexeril exposure and WDHD1 knockdown induced a DNA damage response (DDR) in ESCC cells. In addition, Flexeril significantly inhibited the growth of ESCC tumors in nude mice, downregulating the JAK1-STAT3-WDHD1 signaling pathway, with no significant damage observed in vital organs such as the heart, liver, spleen, lungs, or kidneys, as shown by histological examination.

Flexeril exhibits anti-cancer effects in ESCC by inhibiting the JAK1-STAT3-WDHD1 axis and inducing DDR. These findings suggest that Flexeril may serve as a potential novel therapeutic agent for the treatment of ESCC.

A growing number of antibody‒drug conjugates (ADCs) have been approved for breast cancer treatment. However, the proper sequential strategies of ADCs remain uncertain. Our study aimed to explore the ideal ADC sequential treatment strategies in human epidermal growth factor receptor 2 (HER2)-expressing metastatic breast cancer (MBC).

Our multi-centre retrospective study enrolled MBC patients who received at least 2 lines of different types of ADCs between Jan 1, 2018, and Jul 1, 2024. The efficacy of both ADC1 and ADC2 was evaluated.

A total of 111 patients (83 HER2-positive and 28 HER2-low) were included. In HER2-positive populations, Patients who received ADC2 with a different payload from ADC1 exhibited significantly longer progression-free survival 2 (PFS2) (6.8 vs. 2.7 months, p < 0.001) and overall PFS (progression-free Interval 1 (PFI1) + PFS2) (15.0 vs. 8.5 months, p = 0.043) compared to those treated with ADC2 containing a similar payload with ADC1. Patients received ADC2 immediately after ADC1 progression showed longer PFS2 ADC2 delayed sequential patients (median PFS2: 6.0 vs. 3.0 months, p = 0.004). In HER2-low patients, the efficacy of ADC2 tended to be lower than ADC1 (median PFI1 vs. PFS2: 3.1 vs. 2.4 months, p = 0.078). No significant differences of efficacy were observed, no matter what ADC sequential treatment strategy used.

Sequential treatment with ADCs showed clinical benefit especially for HER2-positive patients treated with ADC2 which have different types of payloads from ADC1. In HER2-low patients, the benefit of ADC sequential therapy seemed to be limited.

Local radiotherapy or surgery is the standard of care for treating brain metastases among patients with breast cancer. However, affected by tumor subtype, more than 50% of human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer and brain metastases will still develop local recurrence or new brain lesions within 1 year after radiotherapy. As systemic therapies demonstrate higher and clinically relevant levels of intracranial activity and longer survival, there is limited evidence to guide how to weigh the options of radiotherapy versus systemic therapy (and deferral of radiation) in patients with progressive brain metastases, particularly those that are symptomatic. This study presents a case of progressive symptomatic HER2-positive brain metastases in a patient previously treated with whole brain radiotherapy and various targeted therapies. Due to limited access to novel HER2-targeted drugs, a new antibody-drug conjugate drug, disitamab vedotin (RC48) monotherapy, was chosen for postprogression treatment. The patient experienced rapid relief of neurological symptoms, partial regression of the brain tumor, and sustained disease remission for over 12 months without any treatment-related toxicity, also avoided reirradiation exposure and potential neurocognitive decline. The treatment of brain metastasis has been a topic of ongoing discussion. Our experience may offer valuable insights into managing HER2-positive progressive symptomatic brain metastases.

Platinum‑resistant ovarian cancer (PROC) is a significant clinical challenge due to the limited number of treatment options and poor outcomes. Moreover, cytotoxic drugs have an unsatisfactory therapeutic efficacy, high toxicity and side effects. An antibody‑drug conjugate (ADC) is a novel cancer therapeutic strategy that combines an antibody, a linker and a payload. ADCs precisely target the tumor cells by binding to the antigen on the surface of tumor cells, thus accurately delivering the cytotoxic drugs and minimizing systemic toxicity. The approval of mirvetuximab soravtansine by the US Food and Drug Administration for treating folate receptor alpha‑positive, platinum‑resistant epithelial ovarian cancer has promoted studies on the use of ADCs in ovarian cancer. A phase III clinical trial showed that mirvetuximab soravtansine achieved an objective remission rate of 42.3% in platinum‑resistant, FRα‑positive ovarian cancer, compared with 15.9% using chemotherapy, demonstrating its immense potential for ADC development. The present review summarizes the research progress on the use of ADCs in PROC as a monotherapy and combination therapy and considers the future development direction of ADCs in PROC.

The heterobifunctional proteolysis targeting chimeras (PROTACs) are a class of emerging therapeutic modalities that enable selective degradation of target proteins in cells. As antibody payloads, they offer several advantages compared to conventional chemical toxins, such as catalytic nature, potent and long-lasting activity, and precise selectivity to avoid systemic toxicity. However, the relatively large size and high hydrophobicity of these chimeric payloads may result in challenging the stability of antibodies, which complicates the in vivo performance. In this work, we use the highly hydrophobic GNE-987 as model PROTAC to evaluate a THIOMAB approach for mitigating the conjugate's hydrophobicity while maintaining the therapeutic potency. We describe an in silico method to select the less hydrophobic site in an antibody and employ the stable tetrapeptide-aminomethoxy linker to conjugate the PROTAC payloads. The resulting degrader-antibody conjugate (J591 DAC) displays antigen-dependent BRD4 degradation and potent cytotoxic activity in PSMA-positive cancer cells. Finally, this DAC, bearing two highly hydrophobic PROTACs, also exhibits a long blood retention and strong antitumor efficacy in mouse models, likely owing to the homogeneous and stable conjugation from the THIOMAB approach. This work provides an example of the design and construction of antibody conjugates with highly hydrophobic payloads.

Brain metastasis remains a significant therapeutic challenge in HER2-positive breast cancer, contributing to poor prognosis and limited treatment options. This review aims to summarize recent advancements in targeted therapies for brain metastasis in HER2-positive breast cancer, with a focus on the efficacy, mechanisms, and clinical implications of antibody-drug conjugates (ADCs) and tyrosine kinase inhibitors (TKIs).

We conducted a comprehensive review of clinical trials, real-world studies, and preclinical research.

This review summarizes the latest clinical and preclinical evidence on targeted therapies for brain metastasis in HER2-positive breast cancer. Key therapies, including trastuzumab deruxtecan (T-DXd) and tucatinib, are discussed, with a focus on their mechanisms, efficacy, and ability to overcome the blood-brain barrier (BBB). Clinical trials such as HER2CLIMB and DESTINY-Breast03, as well as real-world studies, are highlighted to demonstrate the superior intracranial response rates and survival benefits of these therapies.

ADCs and TKIs represent a paradigm shift in the management of brain metastases, offering new hope for patients with HER2-positive breast cancer. Future research should focus on optimizing combination therapies, exploring novel biomarkers, and addressing resistance mechanisms to further improve outcomes. This review underscores the importance of continued innovation in targeted therapies for brain metastasis.

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.

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.

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.

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.

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.

Trastuzumab deruxtecan (T-DXd), a human epidermal growth factor receptor 2 (HER2)-targeted antibody-drug conjugate, demonstrated remarkable efficacy in previously treated patients with HER2-low metastatic breast cancer (mBC), marking a new therapeutic option for this patient population. Prior studies with HER2 PET using 89Zr-radiolabeled antibodies were limited by high rates of imaging false positives for HER2-positive malignancy. In this retrospective study, we investigate whether these false positives (HER2-negative on pathology) could be explained by HER2-low lesions. Methods: A retrospective study was conducted of mBC patients who previously enrolled in 2 prospective HER2 PET imaging trials: NCT02286843 using 89Zr-trastuzumab and 89Zr-pertuzumab and NCT04692831 using 89Zr-ss-pertuzumab. Patients were included if paired HER2 PET scan and biopsy were performed within a 2-mo period. Of 56 total patients, 23 patients met the inclusion criteria. Pathology results for biopsied lesions were collected, without repeat interpretation, and lesions were classified as HER2-positive, HER2-low, or HER2-0. SUVmax of biopsied lesions were compared between pathologic classifications to determine whether lesion uptake intensity could differentiate between HER2-positive and HER2-low lesions. Results: All prior false-positive lesions on HER2 PET scans from NCT02286843 were reclassified as HER2-low (instead of HER2-negative). In the 89Zr-trastuzumab cohort, 3 lesions were HER2-positive (33%) and 6 were HER2-low (67%); in the 89Zr-pertuzumab cohort, 2 were HER2-positive (29%) and 5 were HER2-low (71%). In the 89Zr-ss-pertuzumab cohort (NCT04692831), 7 patients underwent recent biopsies of 8 total lesions demonstrating 1 HER2-positive (12%), 5 HER2-low (62%), and 2 HER2-0 lesions (25%). HER2 PET SUVmax of biopsied lesions were compared between HER2-positive and HER2-low lesions for the combination of all 3 radiotracer cohorts. HER2-low lesions had a significantly higher SUVmax (median, 12.7; interquartile range, 8.05) than did HER2-positive lesions (median, 6.4; interquartile range, 1.98; P = 0.01). Conclusion: HER2 PET imaging with 89Zr-radiolabeled antibodies detects HER2-low lesions in addition to HER2-positive lesions in patients with mBC, suggesting its ability to visualize the entire spectrum of HER2 expression. All prior false positives on 89Zr-trastuzumab and 89Zr-pertuzumab PET scans were reclassified as HER2-low. Lesion SUVmax is not reliable in differentiating HER2-positive from HER2-low lesions; however, it may be useful in distinguishing lesions expressing HER2 from HER2-0 lesions.

Primary and secondary brain tumors have always been a challenge due to their high morbidity and poor prognosis. The incidence of brain metastasis is also increasing with the advent of effective new treatments. Traditional systemic treatments have historically had limited success, partly due to poor central nervous system (CNS) penetration. However, the advent in recent decades of new therapies that have shown high encephalic response rates are challenging this paradigm. ADCs represent a new class of compounds revolutionizing cancer treatment with high systemic response rates and lower toxicities. The continuing evolution of ADCs has shown that certain structural features such as payload, linker, and drug-to-antibody ratio (DAR) are essential in determining their efficacy at the encephalic level, and some ADCs have started to exhibit promising efficacy in treating primary and secondary brain tumors. Unfortunately, most patients with untreated encephalic metastases are excluded from clinical trials, with data primarily from retrospective studies or post hoc analyses. This review describes the early signs of ADC efficacy in brain tumors, the role of complementary treatments like radiation therapy, and critical points to improve ADC efficacy in brain malignancies.

Antibody-drug conjugates (ADCs) are a promising cancer therapy for targeted delivery of drugs to tumor cells. However, resistance to ADCs remains a challenge, necessitating the exploration of combination therapies. A strong biological theory suggests that ADCs interact with cancer cells and immune cells by triggering mechanisms such as immunogenic cell death, dendritic cell activation, and memory T-cell activation, resulting in long-term anti-tumor immunity and ultimately potential synergistic effects with immunotherapy. Based on extensive and reliable preclinical data, several clinical trials are currently combining ADCs with immune checkpoint inhibitors (ICIs) for the treatment of various cancers, including breast, gastric, and non-small-cell lung cancers, to evaluate the safety and anti-tumor activity of the combination therapy. Preliminary evidence from early clinical trials has reported more effective efficacy data. This paper reviews the combination of ADCs and immunotherapy, highlights the key mechanisms by which the two act synergistically, and summarizes the available clinical evidence against different ADCs targets. The paper also explores the re-challenges used for combination therapies and optimized design options for ADCs drugs.

Precision medicine has revolutionized clinical paradigm of lung cancer (LC) patients optimizing therapeutical options on the basis of molecular fingerprinting of tumor cells. The advent of the genomic era contributed to the widespread diffusion of sequencing technologies laying the basis for the approval of an increasing number of clinically relevant predictive biomarkers in clinical settings. In the rapidly evolving scenario of predictive biomarkers, mandatory testing genes demonstrated a statistically significant clinical benefit in LC patients elected to molecular tests, but emerging biomarkers are under investigation to raise the bar in the clinical management of LC patients. To date, promising IHC-based predictive biomarkers emerged as potentially integrative tools in the panel of clinically approved biomarkers. On this basis, genomic, transcriptomic and proteomic data are gaining ground toward "3D" biology" supporting the need of a multidimensional analysis of tumor cells to clinically stratify LC patients. Here we sought to overview the most promising biomarkers investigated in clinical trials to be integrated into diagnostic panel of predictive biomarkers tools for NSCLC patients.

FOLFIRI, a combination of folinic acid, 5-fluorouracil, and irinotecan, is one of the recommended first-line chemotherapeutic treatments for metastatic colorectal cancer. Unfortunately, acquired FOLFIRI resistance represents a common obstacle in the treatment of metastatic colorectal cancer patients. Thus, we aimed to identify mechanisms, gene alterations, and gene expression signatures contributing to acquired FOLFIRI resistance by mimicking this problem in a cell culture model and subsequent translation in clinical data sets. Three FOLFIRI-resistant colorectal cancer (CRC) cell lines were established by continuous FOLFIRI treatment. Comparative mutation screening (161 genes) and transcriptomics (pathway and differential expression analyses) were performed in parental and resistant cells. Data reconciliation was performed in GSE62322, a clinical FOLFIRI responder data set (intrinsic resistance). Relapse-free survival (RFS) associations of identified differentially expressed genes and potential gene signatures were investigated in 8 clinical CRC data sets. No mutual genetic alterations were found in FOLFIRI-resistant derivatives. Resistant cell lines displayed activation of mitogen-activated protein kinase, immune response, and epithelial-mesenchymal transition pathways. Twelve differentially expressed genes, significantly differentially expressed in at least 2 of the 3 resistant cell lines, were identified. Comparison with GSE62322 and subsequent survival analyses revealed a 5-gene FOLFIRI signature comprised of CAV2, TNC, TACSTD2, SERPINE2, and PERP that was associated with RFS in multiple data sets including the cancer genome atlas CRC (hazard ratio [HR] =2.634, P = 4.53 × 10-6), in pooled samples of all data sets (all stages [N = 1981]: HR = 1.852, P = 6.44 × 10-13; stage IV [N = 260]: HR = 2.462, P = 5.22 × 10-9). A multivariate Cox regression analysis identified the 5-gene signature as an independent prognostic factor in the cancer genome atlas data set (HR = 1.89, P = .0202). Our analyses revealed a 5-gene FOLFIRI resistance signature associated with RFS that may help predict FOLFIRI resistance and thus avoid unnecessary ineffective treatment. Signature members might also represent targets to fight FOLFIRI resistance.

The incidence of mortality and morbidity from endometrial cancer (EC) is increasing annually, and there is a paucity of effective targeted therapies for the condition. Antibody-drug conjugates (ADCs) represent a promising approach to tumor-targeted therapy. In this study, we aim to identify a novel molecular target for the preclinical development of EC-targeted ADCs.

Through quantitative and unbiased bioinformatics analyses intercellular adhesion molecule-1 (ICAM1) was identified as a potential cell membrane target. Two ADCs, ICAM1-MMAE and ICAM1-DXd, were subsequently developed by conjugating ICAM1 monoclonal antibodies with microtubule inhibitors and DNA topoisomerase inhibitors, respectively. The preclinical efficacy and biosafety of these ICAM1 ADCs were validated in both in vitro and in vivo models. Furthermore, transcriptomic analysis was conducted to elucidate the therapeutic effects of the ICAM1 ADCs.

Quantitative flow screening and bioinformatics analyses revealed significant overexpression of ICAM1 in EC. ICAM1-MMAE and ICAM1-DXd were developed using clinically effective linkers and payloads. In preclinical models, ICAM1 ADCs showed superior antitumor efficacy compared to standard chemotherapy, achieving sustained tumor regression with an excellent safety profile in both subcutaneous and orthotopic xenograft models. Transcriptomic analysis further revealed that ICAM1-DXd potently activated tumor immunity.

ICAM1 was identified as a promising cell membrane protein target for ADC development in EC. As-synthesized ICAM1 ADCs demonstrated potent antitumor activity, favorable biosafety profiles in vitro and in vivo, and the ability to activate tumor immunity. These findings support the potential of ICAM1 ADCs as a therapeutic strategy and warrant further investigation in clinical studies.

Cancer heterogeneity, characterized by diverse populations of tumorigenic cells, involves the occurrence of differential phenotypes with variable expressions of receptor tyrosine kinases. Aberrant expressions of mesenchymal-epithelial transition (MET) and recepteur d'origine nantais (RON) receptors contribute to the phenotypic heterogeneity of cancer cells, which poses a major therapeutic challenge. This study aims to develop a dual-targeting antibody-drug conjugate (ADC) that can act against both MET and RON for treating cancers with high phenotypic heterogeneity. Through immunohistochemical staining, we show that MET and RON expressions are highly heterogeneous with differential combinations in more than 40% of pancreatic and triple-negative breast cancer cases. This expressional heterogeneity provides the rationale to target both receptors for cancer therapy. A humanized bispecific monoclonal antibody specific to both MET and RON (PCMbs-MR) is generated through IgG recombination using monoclonal antibody sequences specific to MET and RON, respectively. Monomethyl auristatin E is conjugated to PCMbs-MR to generate a dual-targeting ADC (PCMdt-MMAE), with a drug-to-antibody ratio of 4:1. Various cancer cell lines were used to determine PCMdt-MMAE-mediated biological activities. The efficacy of PCMdt-MMAE in vivo is evaluated using multiple xenograft tumor models. PCMdt-MMAE shows a favorable pharmacokinetic profile, with a maximum tolerated dose of ~30 mg/kg in mice. Toxicological studies using Sprague-Dawley rats reveal that PCMdt-MMAE is relatively safe with slight-to-moderate, temporary, and reversible adverse events. Functionally, PCMdt-MMAE induces a robust internalization of both MET and RON and causes a large-scale cell death in cancer cell lines exhibiting MET and RON heterogeneous co-expressions. Both in vitro and in vivo studies demonstrate that the dual-targeting approach in the form of an ADC is highly effective with a long-lasting effect against tumors exhibiting MET/RON heterogeneous phenotypes. Hence, we can suggest that a dual-targeting ADC specific to both MET and RON can be employed as a novel therapeutic strategy for tumors with expressional phenotypic heterogeneity.

Compared with other metastatic sites, breast cancer brain metastases (BCBMs) are associated with the shortest survival time. In addition, human epidermal growth factor receptor 2 (HER2) is observed to be amplified in 20-25% of breast cancer cases where it is a poor prognostic factor for brain metastases. Various anti-HER2 targeted therapies have brought both new opportunities and challenges to patients with HER2-positive BCBM over the past decade. However, prolonging survival time and improving quality of life of patients have become controversial issues in the field of clinical research on BCBMs. On the basis of the latest literature, the present review documents the anti-HER2 targeted drugs applied in patients with HER2-positive BCBM. Further studies on the efficacy and safety of novel HER2-targeted drugs and combined or sequential therapy in clinical treatment are expected to provide more effective strategies for the treatment of patients with HER2-positive BCBM.

Uterine serous carcinoma (USC) is a rare subset of endometrial cancer with a poor prognosis and high recurrence rate. Datopotamab deruxtecan (Dato-DXd) is a novel antibody-drug conjugate (ADC). The objective of this study was to evaluate the preclinical activity of Dato-DXd in USC in vitro against primary USC cell lines with various trophoblast cell-surface antigen 2 (TROP2) expression and in vivo in TROP2-overexpressing cell line-derived mice xenografts. USC primary tumor cell lines were treated with Dato-DXd and a control ADC (CTL ADC) to evaluate cell viability following exposure. Antibody-dependent cell-mediated cytotoxicity against TROP2-overexpressing and -nonexpressing cell lines was evaluated using a 4-hour chromium release assay. USC xenografts in mice were treated with Dato-DXd, CTL ADC, datopotamab, and vehicle to assess the in vivo effects via retro-orbital Dato-DXd administration. We found USC cell lines with TROP2 overexpression to be significantly more sensitive to killing induced by Dato-DXd compared with CTL ADC in vitro (e.g., IC50: 0.11 µmol/L vs. 30.07 µmol/L, P = 0.0074 and 0.11 µmol/L vs. 48.95 µmol/L, P = 0.0127, respectively). Dato-DXd induced antibody-dependent cell-mediated cytotoxicity in the presence of peripheral blood lymphocytes from healthy donors. TROP2-nonexpressing cell lines demonstrated minimal killing by Dato-DXd; however, when admixed with TROP2-overexpressing cells, a significant bystander effect was appreciated. In vivo, mice xenografts overexpressing TROP2 treated with Dato-DXd demonstrated tumor growth suppression and longer overall survival compared with CTL ADC-treated xenografts. These data demonstrate Dato-DXd to be highly active against TROP2-overexpressing USC in vitro and in vivo. Our preclinical activity results warrant future clinical trials for patients with advanced or recurrent USC.

Targeted treatment of USC using the biomarker TROP2 represents a significant opportunity for further treatment options for patients already resistant to other lines of treatment. In this study, we present data showing preclinical evidence of effectiveness of this biomarker-targeted therapy in USC.

Targeted tumor delivery may be required to potentiate the clinical benefit of innate immune modulators. The objective of the study was to apply an antibody-drug conjugate (ADC) approach to STING agonism and develop a clinical candidate.

XMT-2056, a HER2-directed STING agonist ADC, was designed, synthesized, and tested in pharmacology and toxicology studies. The ADC was compared with a clinical benchmark intravenously administered a STING agonist.

XMT-2056 achieved tumor-targeted delivery of the STING agonist upon systemic administration in mice and induced innate antitumor immune responses; single dose administration of XMT-2056 induced tumor regression in a variety of tumor models with high and low HER2 expressions. Notably, XMT-2056 demonstrated superior efficacy and reduced systemic inflammation compared with a free STING agonist. XMT-2056 exhibited concomitant immune-mediated killing of HER2-negative cells specifically in the presence of HER2-positive cancer cells, supporting the potential for activity against tumors with heterogeneous HER2 expression. The antibody does not compete for binding with trastuzumab or pertuzumab, and a benefit was observed when combining XMT-2056 with each of these therapies as well as with trastuzumab deruxtecan ADC. The combination of XMT-2056 with anti-PD-1 conferred benefit on antitumor activity and induced immunologic memory. XMT-2056 was well tolerated in nonclinical toxicology studies.

These data provide a robust preclinical characterization of XMT-2056 and provide rationale and strategy for its clinical evaluation.

Body composition is an important predictor in cancer patients, with skeletal muscle loss and high adiposity associated with poorer prognosis. This study evaluated how body composition affects treatment efficacy in 48 women with metastatic breast cancer receiving trastuzumab deruxtecan. Using computed tomography, skeletal muscle, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were assessed within 60 days before initiating treatment. High SAT and VAT areas were significantly associated with a higher likelihood of dose reductions (Odds Ratio [OR] = 5.34, p = .032 and OR = 5.52, p = 0.032, respectively). Higher SAT areas correlated with a lower objective response rate (OR = 0.22, p = 0.047). Medium SAT and low/medium VAT densities increased the risk of dose reductions. A body mass index over 25 kg/m2 was linked to higher dose reductions (OR = 4.97, p = 0.016). These findings emphasize the need for personalized treatment strategies based on body composition.

Trastuzumab deruxtecan (T-DXd) has been approved for a third- or later-line treatment of HER2-positive advanced gastric cancer (AGC) in Japan. However, clinical data on the use of T-DXd in real-world practice remain insufficient. Although early tumor shrinkage (ETS) serves as an early on-treatment indicator of high treatment sensitivity, the use of ETS in predicting T-DXd efficacy remains unclear.

This study aimed to evaluate the clinical efficacy and safety of T-DXd and investigate the clinical utility of ETS as a predictor of long-term efficacy and survival.

Single-center retrospective cohort study.

This study consecutively enrolled patients with HER2-positive AGC who received T-DXd as a third- or later-line treatment between March 2018 and December 2023. Data on patient characteristics, adverse events (AEs), and clinical outcomes were obtained from electronic medical records. Clinical efficacy was assessed using progression-free survival (PFS) and overall survival (OS). In patients with measurable lesions, the overall response rate (ORR), ETS, and depth of response (DpR) were evaluated. Prognostic outcomes were assessed using the log-rank test and the Cox proportional hazards model.

A total of 65 patients received T-DXd, with a median age of 66 years (range, 31-82 years); 77% had HER2 immunohistochemistry score of 3+, 71% received T-DXd as a third-line treatment, and 32% required initial dose reduction. At a median follow-up of 33.6 months, the median PFS and OS were 4.5 months and 7.7 months, respectively. Among the 47 patients with measurable lesions, the ORR was 36%. A median DpR of 15.8% was observed, with higher DpR correlating with longer OS. ETS was achieved in 38% of the patients and was an independent predictor of favorable PFS (hazard ratio (HR), 0.21; 95% confidence interval (CI), 0.09-0.49; p < 0.01) and OS (HR, 0.23; 95% CI, 0.10-0.52; p < 0.01). Longer second-line treatment duration was independently associated with improved OS. Overall, grade ⩾ 3 AEs occurred in 37% of the patients. Initial dose reduction reduced AE-induced discontinuation of treatment without compromising efficacy.

T-DXd demonstrated notable efficacy and a manageable safety profile in patients with HER2-positive AGC. Rapid and deep tumor shrinkage may have a significant impact on survival.

Antibody-dependent cellular cytotoxicity (ADCC) is a critical mechanism by which therapeutic antibodies leverage the immune system to target and eliminate cancer cells. The key agents of ADCC are natural killer (NK) cells, specifically targeting antibody-covered cancer cells through the CD16 receptor. While other immune cells and Fc receptors can contribute and enhance ADCC, NK cells and the CD16 receptor are crucial for the efficacy of cancer therapies such as trastuzumab, cetuximab and rituximab. Co-culture assays are essential for understanding the mechanisms of these therapies, overcoming resistance and optimizing novel therapeutic antibodies. This review highlights the importance of measuring ADCC to assess the efficacy of therapeutic antibodies. Here we also present the various in vitro models and assay methodologies available for studying ADCC, comparing the strengths and limitations of approaches like using PBMCs to better reflect real-life conditions or NK cell lines for standardization. It also covers different readouts for ADCC, either focusing on effector cells activation, including reporter and degranulation assays or in the target cell killing, including different molecule release assays, flow cytometry and immunofluorescence techniques. Selecting the best model for studying ADCC is crucial for the translational significance of therapeutic antibody research.

As novel human epidermal growth factor receptor-2 (HER2) and drug conjugates have proven to be effective treatments for both HER2-positive breast cancer (BC) and HER2-low BC, the need to develop more accurate methods to quantify HER2 status has increased. We compared the correlation between the HER2 mRNA score (HS), obtained using the Oncotype DX (ODX) test, and HER2 immunohistochemistry (IHC) to verify the accuracy of HER2 quantification and its correlation with clinicopathologic characteristics. We retrospectively collected ODX test data from 1524 estrogen-receptor positive, HER2-negative patients with BC. No significant differences in clinicopathologic characteristics, including ODX Recurrence Score (RS), were observed between HER2-0 and HER2-low BC. The median HS value of the HER2-low subgroup was significantly higher than that of the HER2-0 subgroup ( P <0.001) and increased significantly between the 4 subgroups classified by HER2 IHC ( P <0.001). The receiver operating characteristic curve showed acceptable utility in distinguishing HER2-0 from HER2-low (area under the curve=0.76) and HER2-null and HER2-ultralow subgroups (area under the curve=0.81), but the overlap between subgroups was also prominent. After defining 8.9 as a suboptimal cutoff mRNA score, multivariate analysis revealed that low Ki-67 (<20%) and RS (≤25) were statistically associated with higher HS (>8.9), whereas progesterone receptor negativity, high Ki-67, high nuclear grade, lower HS, and older age (>50 y) were statistically associated with high RS. Our study revealed that HS is significantly associated with HER2 IHC results and clinicopathologic parameters other than HER2 IHC.

There are three categories of drugs that treat human epidermal growth factor receptor type 2 (HER-2) positive breast cancer: monoclonal antibodies (mAbs), antibody-drug conjugates (ADCs), and tyrosine kinase inhibitors (TKIs). The purpose of this study is to analyze and compare the adverse reactions of three classes of anti-HER-2 drugs to various body systems in patients based on the FDA Adverse Event Reporting System (FAERS).

All data reports were extracted from the FAERS between 2004 and 2024. Data mining of adverse events associated with anti-HER-2 drugs was carried out using disproportionality analysis. A multivariate logistic regression analysis was conducted to explore the risk factors associated with AEs leading to hospitalization.

A total of 47,799 patients were screened for the three classes of drugs, among which ADC drugs caused the largest proportion of deaths. MAb has the strongest ADR signals associated with "cardiac disorders". Moreover, trastuzumab was associated with a greater risk of cardiotoxicity. Logistic regression analysis revealed that the treatment with mAbs should be wary of serious adverse reactions in "infections and infestations" and "metabolism and nutrition disorders". Moreover, "endocrine disorders" were the factor associated with the highest risk of prolonged hospitalization due to trastuzumab deruxtecan (T-DXd). The safety of tucatinib among TKI drugs is greater than that of other drugs.

In general, from the perspective of the effects of the three classes of drugs on the various body systems of patients, we should focus on mAb-associated "cardiac disorders", ADC-associated "hepatobiliary disorders", "respiratory, thoracic and mediastinal disorders", and TKI-associated "gastrointestinal disorders.

Gastric cancer, marked by its high incidence and poor prognosis, demands the urgent development of novel and effective treatment strategies, especially for patients ineligible for surgery or those who have had limited success with chemotherapy, radiotherapy and targeted therapies. Recently, antibody-drug conjugates (ADCs) have become a key area of investigation due to their high specificity and potent antitumor effects. These therapies combine monoclonal antibodies, designed to bind to tumor-specific antigens, with cytotoxic agents that selectively target and destroy malignant cells. ADCs have generated significant interest in clinical trials as a promising approach to improve both treatment efficacy and patient outcomes in gastric cancer. However, their clinical application is not without challenges and limitations that must be addressed. This review discusses the recent progress in the use of ADCs for gastric cancer treatment.

Breast cancer was previously categorized as human epidermal growth factor receptor 2 (HER2)-positive (immunohistochemistry [IHC] 3+, IHC 2+ / in situ hybridization [ISH]-positive) or HER2-negative (IHC 0, IHC 1+, IHC 2+/ISH-). Recent studies of trastuzumab deruxtecan, a HER2-directed antibody-drug conjugate, have explored the spectrum of HER2 expression in tumors categorized as HER2-negative, including HER2-low (IHC 1+, IHC 2+/ISH-) and HER2-ultralow (IHC 0 with membrane staining). Clinical relevance of HER2-low and HER2-ultralow is reinforced by encouraging efficacy findings in these populations.

To assess HER2-low and HER2-ultralow scoring performance by pathologists, and compare real-world HER2-low scoring with centralized scoring by trained pathologists.

Formalin-fixed, paraffin-embedded breast cancer samples stained by the VENTANA anti-HER2/neu (4B5) Rabbit Monoclonal Primary Antibody (Roche) assay were selected to ensure adequate representation across all HER2 IHC scores (N = 500). Samples were rescored in a central laboratory by three pathologists trained in HER2-low scoring, and a majority consensus generated. Agreement between consensus and historical real-world HER2 scores was assessed by Fleiss' kappa across HER2 scores (IHC 0, 1+, 2+, 3+).

Substantial agreement was observed among central pathologists across HER2 scores (κ = 0.69), for the HER2-low cutoff (IHC 0 vs. IHC 1+, 2+, 3+; κ = 0.79), and the HER2-ultralow cutoff (IHC 0 absent membrane staining vs. IHC 0 with membrane staining, 1+, 2+, 3+; κ = 0.68). Substantial agreement was observed between real-world pathologists and central consensus for the HER2-low cutoff (κ = 0.72).

Pathologists can reproducibly score HER2-low and HER2-ultralow when supported by training. Findings may aid decision-making for patients with breast cancer who are potentially eligible for HER2-directed therapy.

Antibody-drug conjugates (ADCs) have emerged as a rapidly expanding class of therapeutics driven by their superior specificity and clinical efficacy. 14 out of 16 commercially approved ADCs are formulated as lyophilized forms because ADC is generally considered to be less stable than unmodified antibody. The formulation development for ADCs, particularly liquid formulation, presents unique challenges due to their intricate structural complexity, physicochemical properties, and degradation pathways. This review provides the first comprehensive analysis of formulation strategies employed in commercial ADCs. Furthermore, this review discusses the key areas of focus for ADCs throughout the formulation development workflow, spanning from the initial formulation development to the final stage of drug product manufacturing. In addition, we identify and analyze the distinctive technical challenges in ADC formulation development compared to unconjugated antibody, while proposing potential solutions to these challenges. Finally, we offer strategic perspectives on future directions in ADC formulation development to advance this promising therapeutic modality.

Nausea and vomiting are common, distressing side effects associated with chemotherapeutic regimens, resulting in reduced quality of life and treatment adherence. Appropriate antiemetic prophylaxis strategies may reduce/prevent chemotherapy-induced nausea and vomiting (CINV). Historically, investigators assessed antiemetics up to 120 hours after chemotherapy. However, CINV can extend beyond this time. Thus, the effect of antiemetics during the long-delayed period (>120 hours) requires investigation. Emerging treatment options, including certain antibody-drug conjugates (ADCs), are associated with high rates of acute and late-onset nausea and vomiting that can last for extended duration. With the increasing number of ADCs approved and in development, there is urgency to control nausea and vomiting in patients receiving these new therapies. In this narrative review, we present the emetogenic potential of ADCs and CINV in the long-delayed period along with antiemetic prophylaxis strategies used to date. We also discuss the promising role of the fixed-combination antiemetic NEPA ([fos]netupitant plus palonosetron) in controlling long-delayed nausea and vomiting, addressing characteristics that may contribute to its longer efficacy duration compared to other antiemetics. Finally, we highlight encouraging results with NEPA in patients receiving the ADCs trastuzumab deruxtecan or sacituzumab govitecan, which suggest NEPA may be an effective antiemetic prophylaxis in these settings.

Biliary tract cancers (BTCs) constitute a heterogeneous group of malignancies with rising incidence and limited therapeutic options in advanced stages, leading to increased overall mortality. Extensive genomic profiling has identified key oncogenic drivers in BTCs that represent promising therapeutic targets and could change the treatment paradigm. Evidence suggests improved survival outcomes for patients with actionable molecular alterations who received matched targeted therapies. Human epidermal growth factor receptor 2 (HER2) is a receptor tyrosine kinase and proto-oncogene that has been extensively studied as a prognostic biomarker and a therapeutic target in multiple solid organ malignancies. Recent clinical trials on the combination of trastuzumab with tucatinib, FOLFOX, or pertuzumab for previously treated, HER2-positive, advanced BTCs have shown improved outcomes compared to current second-line therapies. Early evidence from observational studies on trastuzumab-containing regimens as first-line suggests promising efficacy. Furthermore, the recent tumor-agnostic approval of trastuzumab deruxtecan for HER2-positive solid tumors has formally introduced HER2-directed agents in the BTC therapeutic arsenal. This review aims to summarize the rapidly evolving landscape of HER2-directed agents for BTCs, highlighting current evidence of survival benefit. Beginning with a concise presentation of the structural and functional aspects of HER2, we detail the frequency and prognostic significance of HER2 alterations in BTCs and discuss all available preclinical and clinical data on anti-HER2 agents tested for BTCs.

Trastuzumab Deruxtecan (T DXD), a new antibody drug conjugate is a new treatment option for 2nd line metastatic breast cancer (MBC) for HER2 + or HER2 low tumors. Palliative or ablative radiotherapy (RT) may be required in patients who are being treated with T-DXd. However there is a lack of evidence regarding the safety profile of combining T-DXd with RT. TENDANCE study aimed to evaluate safety and efficacy of combined T-DXd and RT.

This retrospective multicenter study included 54 patients treated concurrently with T-DXd and RT for HER2+ and HER2 low MBC between February 2021 and December 2023. All data were collected from a web-questionnaire, centralized after medical records and validation of the protocol by the local ethical committee. Primary endpoint was the safety of combined therapy.

Median age was 60 years. Patients who received T-DXD were further categorized into HER2+ (40.7 %), HER2 low/hormonal receptors HR+ (40.8 %) or HER2 low/HR- (18.5 %). In the HER2+ patients, T-DXd was administered as 2nd (18.2 %) or 3rd (31.8 %) or 4th (50 %) line therapy. RT was delivered using palliative (72.2 %) or ablative doses (27.8 %). Indications consisted mostly of palliative bone irradiation (46.3 %) and stereotactic radiosurgery (SRS) (25.9 %). With the median follow-up of 9 months, 22.2 % of patients had a complete response and 77.8 % had either a partial response or stable disease. Grade 1 or 2 asthenia was observed in 51.8 % of patients, while only 16.6 % experienced other grade 1 or 2 adverse effects. There was no T-DXd therapy discontinuation related to RT.

To our knowledge, TENDANCE is the largest study evaluating concurrent T-DXd and RT. This preliminary report suggests the feasibility of the combination of RT and T-DXd with manageable toxicity rate. Longer follow-up and further prospective studies are required to confirm these results.

Cancer is the second-highest cause of death worldwide. Accordingly, finding new cancer treatments is of great interest to researchers. The current platforms to fight cancer such as chemotherapy, radiotherapy, and surgery are limited in efficacy, especially in the metastatic setting. In this war against cancer, the immune system is a powerful ally, but tumor cells often outsmart it through alternative pathways. Cluster of differentiation 47 (CD47), a protein that normally prevents healthy cells from being attacked by immune cells, is often overexpressed on cancer cells. This makes CD47 a prime target for immunotherapy. Blocking of CD47 has the potential to unleash the immune system's cell populations-such as myeloid cells, macrophages, and T cells-to allow the immune system to discover and destroy cancer cells more successfully. In this review, we aimed to provide the latest information and findings about the roles of CD47 in the regulation of various cellular pathways and, thus, the importance of CD47 as a potential target in cancer therapy.

HER2-targeting therapies are well-described in breast, gastric, and lung cancers, however accumulating data supports a role for HER2-targeted therapies in gynecologic cancers. Despite varied methodologies for HER2 testing, evidence supports that a substantial proportion of endometrial, ovarian, cervical, and vulvar cancers overexpress HER2. This underscores the rationale for HER2-targeted therapies in these malignancies, including the use of HER2-directed tyrosine kinase inhibitors, antibody-drug conjugates, and immune-stimulating antibody conjugates. Understanding mechanisms of resistance to HER2-targeted therapies will inform possible combinatorial strategies.

Trastuzumab rezetecan (also known as SHR-A1811) is a novel antibody-drug conjugate consisting of a humanised HER2-directed monoclonal antibody, cleavable tetrapeptide-based linker, and DNA topoisomerase I inhibitor. In the phase 1 portion of this phase 1/2 study, trastuzumab rezetecan showed preliminary anti-tumour activity and a favourable safety profile in patients with HER2-mutant non-small-cell lung cancer (NSCLC). We present phase 2 results from the study, which aimed to further evaluate the activity and safety of trastuzumab rezetecan at the recommended dose.

In this multicentre, single-arm, phase 2 trial, conducted in 35 hospitals in China, we recruited patients aged 18-75 years, with locally advanced or metastatic NSCLC with an activating HER2 mutation and an Eastern Cooperative Oncology Group performance status score of 0-1, who had disease progression after or were intolerant to platinum-based chemotherapy and anti-PD-1 treatment or anti-PD-L1 treatment. Trastuzumab rezetecan was administered at 4·8 mg/kg intravenously once every 3 weeks. The primary endpoint was objective response rate assessed by an independent review committee in patients who received at least one cycle of study treatment. All patients who received at least one cycle of study treatment were included in safety analyses. This study is registered with ClinicalTrials.gov, NCT04818333, and is ongoing but not recruiting.

Between April 14, 2023, and Dec 14, 2023, 94 patients were enrolled and treated. 42 (45%) patients were male, 52 (55%) female, 92 (98%) were Han Chinese, and two (2%) were other ethnicity Chinese. At data cutoff (June 14, 2024), the median duration of follow-up was 8·7 months (IQR 7·0-10·4). 69 (73%; 95% CI 63·3-82·0) of 94 patients had a confirmed objective response, as assessed by independent review committee. The most common grade 3-4 treatment-related adverse events were decreased neutrophil count (38 [40%] patients), decreased white blood cell count (25 [27%]), anaemia (22 [23%]), decreased platelet count (10 [11%]), and decreased lymphocyte count (seven [7%]). Treatment-related serious adverse events occurred in 22 (23%) patients, which were decreased platelet count (six [6%]), decreased neutrophil count (six [6%]), interstitial lung disease (five [5%]), decreased white blood cell count (four [4%]), anaemia (four [4%]), vomiting (three [3%]), pneumonia (three [3%]), hyponatraemia (two [2%]), and pyrexia (one [1%]), small intestinal obstruction (one [1%]), nausea (one [1%]), and chronic obstructive pulmonary disease (one [1%]). There were no treatment-related deaths.

Trastuzumab rezetecan showed clinically meaningful activity and manageable safety in patients with previously treated HER2-mutant NSCLC. Further trials are justified.

Jiangsu Hengrui Pharmaceuticals, National Multi-disciplinary Treatment Project for Major Diseases, Collaborative Innovation Center for Clinical and Translational Science by the Ministry of Education & Shanghai.

For the Chinese translation of the abstract see Supplementary Materials section.

Antibody-drug conjugates (ADCs) with camptothecin derivatives as payloads have been a hot topic of interest and research since the launch of DS-8201a. As an important component of ADCs, the adequate stability of the linker during circulation and its rapid release at the target site are crucial for the efficient efficacy of ADCs. Although traditional quaternary ammonium ADCs based on dipeptide linkers were highly stable and could be released by specific enzymes, their poor in vitro anti-tumor activity had limited their further exploration. We applied a methylsulfonylethylamine-modified MAC self-elimination system to a valine-alanine linker and constructed a quaternary ammonium ADC (HER2-11) that combines both stability and cleavability. The optimization of the linker effectively improved the in vitro cellular activity of conventional quaternary ammonium ADCs, but the complex intracellular cleavage mechanism of HER2-11 resulted in a weaker anti-tumor activity compared to HER2-GGFG-DXd, which provides great reference value for the continued research of this type of linker in the future.

Antibody drug conjugates (ADCs) are a novel class of therapeutics that structurally are composed by an antibody directed to a tumor epitope connected via a linker to a cytotoxic payload, and that have shown significant antitumor activity across a range of malignancies including lung cancer. In this article we review the pharmacology and design of ADCs, as well as we describe the results of different studies evaluating ADCs in lung cancer directed to several targets including HER2, HER3, TROP2, MET, CEACAM5 and DLL3.

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.