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Aims: This study aims to develop a generalized pharmacokinetic (PK) model for monomethyl auristatin E (MMAE)‐based antibody–drug conjugates (ADCs) that can simultaneously capture the PK of multiple ADC analytes commonly measured in the clinic. Methods: A comprehensive literature review was conducted to collect PK data on MMAE‐based ADCs from clinical trials. From each study, PK profiles of total antibody, the ADC, conjugated MMAE, and unconjugated MMAE, were extracted. These data were pooled and dose‐normalized to evaluate the generalizability of PK across various ADCs and dose levels. Upon confirming PK generalizability, a generalized PK model for MMAE‐based ADCs was developed using the entire dataset. Furthermore, exposure metrics (Cmax and AUC) reported across the range of doses were combined to establish linear relationships between dose and exposure metrics for MMAE‐based ADCs. Results: A total of 109 PK profiles from 18 distinct MMAE‐based ADCs were gathered. The dose‐normalized PK profiles supported the generalizability of PK for MMAE‐based ADCs. A generalized PK model was developed, which enabled capturing the PK data for 4 ADC analytes across all collected MMAE‐based ADCs. A linear relationship between dose and PK exposure metrics was established, enabling the prediction of typical exposure values across different doses for MMAE‐based ADCs. Conclusions: This study comprehensively analysed clinical PK data from different valine–citrulline (vc)‐MMAE‐based ADCs. The generalized PK model developed here serves as an important tool for a priori prediction of the PK for multiple ADC analytes in clinical settings and lays the foundation for establishing generalized exposure–response and exposure–toxicity correlations for MMAE‐based ADCs. [ABSTRACT FROM AUTHOR]

Aims Methods Results Conclusion To evaluate relationships between plasma concentrations of belantamab mafodotin, total monoclonal antibody, and its payload and changes in electrocardiogram (ECG) parameters in patients with relapsed or refractory multiple myeloma from the DREAMM‐1 and DREAMM‐2 studies.Hysteresis plots and linear regression analyses of pharmacokinetic (PK) analyte (belantamab mafodotin, total monoclonal antibody, and cytotoxic cysteine‐maleimidocaproyl monomethyl auristatin F payload) concentrations vs. time‐matched ECG parameters (absolute/change from baseline in QT interval corrected for RR interval [QTc/ΔQTc] and QT interval corrected for heart rate by Fridericia's formula [QTcF/ΔQTcF]) were performed. Concentrations of PK analyte required for a 10‐ms increase in QTc in DREAMM‐2 were calculated via simulation, as was the probability of ΔQTc/ΔQTcF exceeding 10 ms for the expected Cmax of PK analyte concentrations associated with the doses (2.5 and 3.4 mg/kg) administered in DREAMM‐2.Time‐matched PK and ECG data from 290 patients (DREAMM‐1, n = 73; DREAMM‐2, n = 217) were analysed. Hysteresis plots did not clearly indicate any concentration‐related prolongation in QTc or QTcF; regression analyses indicated a very small rate of increase in ΔQTc and ΔQTcF with increasing concentrations of PK analytes. Calculated concentrations of PK analyte required for a 10‐ms prolongation in QTc were higher than the maximum analyte concentrations observed following treatment with belantamab mafodotin in DREAMM‐2; the probability that each dose would prolong ΔQTc and ΔQTcF by >10 ms was 0 and <0.25%, respectively.This study of belantamab mafodotin and its payload did not provide evidence of QT prolongation in patients with relapsed or refractory multiple myeloma at clinically relevant doses. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion To evaluate the potential utility of antibody‐drug conjugates targeting trophoblast cell surface antigen‐2 (TROP‐2) in patients with primary penile squamous cell carcinoma (PSCC), patients with recurrence (REC cohort), and patient‐matched distant metastases (MET cohort), and to assess the potential use of TROP‐2 as a predictive non‐invasive biomarker in PSCC.A cohort comprising a PRIM (n = 37), REC (n = 5) and MET subcohort (n = 7), with MET including lymph node and lung metastases, was analysed using quantitative real‐time PCR, ELISA and immunohistochemical staining with evaluation of H‐score.TROP‐2 mRNA and serum protein levels were significantly increased in primary and recurrent PSCC compared to cancer‐free controls (both P < 0.001). Immunohistochemical analysis revealed that most of the PRIM cohort (n = 34/37, median H‐score 260, interquartile range [IQR] 210–300), as well as all patients in the REC (median [IQR] H‐score 200 [165–290]) and MET cohorts (median [IQR] H‐score 280 [260–300]) exhibited moderate to strong membranous TROP‐2 expression. Additionally, The H‐score (membranous TROP‐2 expression) was positively correlated with TROP‐2 mRNA (ρ = 0.69, P < 0.0001, R2 = 0.70) and protein levels (ρ = 0.86, P < 0.0001, R2 = 0.59), indicating its potential as a non‐invasive biomarker in PSCC.In summary, our results support further studies on TROP‐2 as a diagnostic and therapeutic target in primary, recurrent and metastatic PSCC. [ABSTRACT FROM AUTHOR]

Purpose: Improved survival rates have been observed in castration‐resistant prostate cancer (CRPC) due to advancements in treatment options. However, individuals with brain metastases still have limited therapeutic options and an unfavorable prognosis. Therefore, there is an urgent need to explore new therapeutic avenues, such as antibody‐drug conjugates (ADCs), which have demonstrated significant clinical activity against active brain metastases in solid tumors. Our objective was to determine the expression levels of the ADC targets Trop‐2 and NECTIN‐4 in cerebral metastasized CRPC (mCRPC). Methods: Immunohistochemical staining of Trop‐2 and NECTIN‐4 with evaluation of H‐score was performed in CRPC brain metastases (n = 31). Additionally, we examined Trop‐2 protein expression in prostate cancer cell lines and studied their responsiveness to the anti‐Trop‐2 ADC Sacituzumab govitecan (SG) in vitro. Results: Our analysis revealed that most patients exhibited moderate to strong Trop‐2 expression [n = 27/31 with H‐score ≥100, median H‐score 220 (IQR 180–280)], while NECTIN‐4 was absent in all cerebral metastases. Mechanistically, we demonstrated that the efficacy of SG depends on Trop‐2 expression levels in vitro. Overexpression of Trop‐2 in Trop‐2‐negative PC‐3 cells led to sensitization to SG, whereas CRISPR‐Cas9‐mediated knockdown of Trop‐2 in Trop‐2‐expressing DU‐145 cells conferred resistance to SG. Conclusion: The substantial expression of Trop‐2 in cerebral metastases, along with our preclinical in vitro results, supports the efficacy of SG in treating cerebral mCRPC. Thus, our results extend the understanding of the potential of ADCs in prostate cancer treatment and provide an additional treatment strategy for the challenging subset of patients with cerebral metastases. [ABSTRACT FROM AUTHOR]

Polatuzumab vedotin is a CD79b‐directed antibody–drug conjugate that targets B cells and delivers the cytotoxic payload monomethyl auristatin E (MMAE). The phase III POLARIX study (NCT03274492) evaluated polatuzumab vedotin in combination with rituximab, cyclophosphamide, doxorubicin, and prednisone (R‐CHP) as first‐line treatment of diffuse large B‐cell lymphoma (DLBCL). To examine dosing decisions for this regimen, population pharmacokinetic (popPK) analysis, using a previously developed popPK model, and exposure–response (ER) analysis, were performed. The popPK analysis showed no clinically meaningful relationship between cycle 6 (C6) antibody‐conjugated (acMMAE)/unconjugated MMAE area under the concentration–time curve (AUC) or maximum concentration, and weight, sex, ethnicity, region, mild or moderate renal impairment, mild hepatic impairment, or other patient and disease characteristics. In the ER analysis, C6 acMMAE AUC was significantly associated with longer progression‐free and event‐free survival (both p = 0.01). An increase of <50% in acMMAE/unconjugated MMAE exposure did not lead to a clinically meaningful increase in adverse events of special interest. ER data and the benefit–risk profile support the use of polatuzumab vedotin 1.8 mg/kg once every 3 weeks with R‐CHP for six cycles in patients with previously untreated DLBCL. [ABSTRACT FROM AUTHOR]

Objective: In December 2021, enfortumab vedotin (EV), an antibody‐drug conjugate directed against nectin‐4, was approved in Japan as a new treatment after platinum‐containing chemotherapy and PD‐1/PD‐L1 inhibitors. This study evaluated, using real‐world data, the efficacy and safety of EV therapy in patients with metastatic urothelial carcinoma (mUC). Materials and methods: Fifty‐five patients with mUC who discontinued pembrolizumab therapy due to disease progression between June 2018 and April 2023 at Yokohama City University Hospital were evaluated retrospectively. Of the 55 patients, 25 received EV therapy (EV group) and 30 did not (non‐EV group). All patients who underwent EV therapy were diagnosed with disease progression after the approval of EV in Japan. Results: The median (range) follow‐up period after pembrolizumab discontinuation was 6.3 (0.7–31.1) months. There were eight (32.0%) deaths due to cancer in the EV group and 27 (90.0%) in the non‐EV group. The overall survival (OS) after pembrolizumab discontinuation was not reached in the EV group versus 2.6 months in the non‐EV group (p < 0.001). A multivariate analysis revealed that EV therapy (EV vs. non‐EV group; hazard ratio 0.26; 95% confidence interval 0.16–0.41; p < 0.001) was an independent prognostic factor for OS. Conclusion: EV prolonged OS in mUC following pembrolizumab therapy in real‐world data. [ABSTRACT FROM AUTHOR]

First‐line treatment of multiple myeloma, a prevalent blood cancer lacking a cure, using anti‐CD38 daratumumab antibody and lenalidomide is often inadequate due to relapse and severe side effects. To enhance drug safety and efficacy, an antibody‐drug conjugate, TE‐1146, comprising six lenalidomide drug molecules site‐specifically conjugated to a reconfigured daratumumab to deliver cytotoxic lenalidomide to tumor cells is developed. TE‐1146 is prepared using the HighDAR platform, which employs i) a maleimide‐containing "multi‐arm linker" to conjugate multiple drug molecules creating a drug bundle, and ii) a designed peptide with a Zn2+‐binding cysteine at the C‐termini of a reconfigured daratumumab for site‐specific drug bundle conjugation. It is shown that TE‐1146 remains intact and effectively enters CD38‐expressing tumor cells, releasing lenalidomide, leading to enhanced cell‐killing effects compared to lenalidomide/daratumumab alone or their combination. This reveals the remarkable potency of lenalidomide once internalized by myeloma cells. TE‐1146 precisely delivers lenalidomide to target CD38‐overexpressing tumor cells. In contrast, lenalidomide without daratumumab cannot easily enter cells, whereas daratumumab without lenalidomide relies on Fc‐dependent effector functions to kill tumor cells. [ABSTRACT FROM AUTHOR]

Although natural products are essential sources of small‐molecule antitumor drugs, some can exert substantial toxicities, limiting their clinical utility. Anthraquinone‐fused enediyne natural products are remarkably potent antitumor drug candidates, and uncialamycin and tiancimycin (TNM) A are under development as antibody‐drug conjugates. Herein, a novel drug delivery system is introduced for TNM A using anti‐human epidermal growth factor receptor 2 (HER2) immunoliposomes (ILs). Trastuzumab‐coated TNM A‐loaded ILs (HER2‐TNM A‐ILs) is engineered with an average particle size of 182.8 ± 2.1 nm and a zeta potential of 1.75 ± 0.12 mV. Compared with liposomes lacking trastuzumab, HER2‐TNM A‐ILs exhibited selective toxicity against HER2‐positive KPL‐4 and SKBR3 cells. Coumarin‐6, a fluorescent TNM A surrogate, is encapsulated within anti‐HER2 ILs; the resultant ILs have enhanced cellular uptake in KPL‐4 and SKBR3 cells when compared with control liposomes. Furthermore, ILs loaded with more Cy5.5 accumulated in KPL‐4 mouse tumors. A single HER2‐TNM A‐IL dose (0.02 mg kg−1) suppressed the growth of HER2‐positive KPL‐4 mouse tumors without apparent toxicity. This study not only provides a straightforward method for the effective delivery of TNM A against HER2‐positive breast tumors but also underscores the potential of IL‐based drug delivery systems when employing highly potent cytotoxins as payloads. [ABSTRACT FROM AUTHOR]

Summary: Systemic light chain (AL) amyloidosis is a relapsing plasma cell disorder. Therapy is limited, particularly for triple‐class refractory disease. We report the use of belantamab mafodotin, a BCMA‐directed drug–antibody conjugate, for relapsed AL amyloidosis, including patients traditionally excluded from clinical trials. Thirty‐one patients were reviewed, with a median of three prior lines of therapy. The median follow‐up was 12 months (95% CI 4–19), and a median of five doses were delivered. The best haematological overall response rate was 71%, and the complete/very good partial response was 58%. Sixty‐eight percent had keratopathy and improved in all. Belantamab mafodotin has high efficacy and good tolerability in patients with relapsed AL amyloidosis. [ABSTRACT FROM AUTHOR]

Objective: The aim of the present study was to evaluate the expression of intracellular and vesicular LGALS3BP in oral squamous cell carcinoma (OSCC) patients and available cell lines to explore its potential as a target for antibody‐drug conjugate (ADC) therapy. Methods: Free and vesicular LGALS3BP expression levels were evaluated in cancer tissues from a cohort of OSCC patients as well as in a panel of OSCC cell lines through immunohistochemistry, qRT‐PCR, Western Blot analysis, and ELISA. Results: LGALS3BP resulted in being highly expressed in the cytoplasm of tumour cells in OSCC patient tissues. A strong correlation was found between high LGALS3BP expression levels and aggressive histological features of OSCC. Biochemistry analysis performed on OSCC cell lines showed that LGALS3BP is expressed in all the tested cell lines and highly enriched in cancer‐derived extracellular vesicles. Moreover, LGALS3BP high‐expressing HOC621 and CAL27 OSCC cell lines showed high sensitivity to the ADC‐payload DM4, with an IC50 around 0.3 nM. Conclusions: The present study highlights that LGALS3BP is highly expressed in OSCC suggesting a role as a potential diagnostic biomarker and therapeutic target for ADC‐based therapy. [ABSTRACT FROM AUTHOR]

Rationale: A common strategy for antibody-drug conjugate (ADC) quantitation from in vivo study samples involves measurement of total antibody, conjugated ADC, and free payload concentrations using multiple reaction monitoring (MRM) mass spectrometry. This not only provides a limited picture of biotransformation but can also involve lengthy method development. Quantitation of ADCs directly at the intact protein level in native conditions using high-resolution mass spectrometers presents the advantage of measuring exposure readout as well as monitoring the change in average drug-to-antibody ratio (DAR) and in vivo stability of new linker payloads with minimal method development. Furthermore, site-specific cysteineconjugated ADCs often rely on non-covalent association to retain their quaternary structure, which highlights the unique capabilities of native mass spectrometry (nMS) for intact ADC quantitation. Methods: We developed an intact quantitation workflow involving three stages: automated affinity purification, nMS analysis, and data processing in batch fashion. The sample preparation method was modified to include only volatile ion-pairing reagents in the buffer systems. A capillary size-exclusion chromatography (SEC) column was coupled to a quadrupole time-of-flight high-resolution mass spectrometer for highthroughput nMS analysis. Samples from two mouse pharmacokinetic (PK) studies were analyzed using both intact quantitation workflow and the conventional MRM-based approach. Results: A linear dynamic range of 5-100 µg/mL was achieved using 20 µL of serum sample volume. The results of mouse in vivo PK measurement using the intact quantitation workflow and the MRM-based approach were compared, revealing excellent method agreement. Conclusions: We demonstrated the feasibility of utilizing nMS for the quantitation of ADCs at the intact protein level in preclinical PK studies. Our results indicate that this intact quantitation workflow can serve as an alternative generic method for highthroughput analysis, enabling an in-depth understanding of ADC stability and safety in vivo. [ABSTRACT FROM AUTHOR]

Existing antibody–drug conjugate (ADC) linkers, whether cleavable or non‐cleavable, are designed to release highly toxic payloads or payload derivatives upon internalisation of the ADCs into cells. However, clinical studies have shown that only <1 % of the dosed ADCs accumulate in tumour cells. The remaining >99 % of ADCs are nonspecifically distributed in healthy tissue cells, thus inevitably leading to off‐target toxicity. Herein, we describe an intelligent tumour‐specific linker strategy to address these limitations. A tumour‐specific linker is constructed by introducing a hypoxia‐activated azobenzene group as a toxicity controller. We show that this azobenzene‐based linker is non‐cleavable in healthy tissues (O2 >10 %), and the corresponding payload derivative, cysteine‐appended azobenzene‐linker–monomethyl auristatin E (MMAE), can serve as a safe prodrug to mask the toxicity of MMAE (switched off). Upon exposure to the hypoxic tumour microenvironment (O2<1 %), this linker is cleaved to release MMAE and fully restores the high cytotoxicity of the ADC (switched on). Notably, the azobenzene linker‐containing ADC exhibits satisfactory antitumour efficacy in vivo and a larger therapeutic window compared with ADCs containing traditional cleavable or non‐cleavable linkers. Thus, our azobenzene‐based linker sheds new light on the development of next‐generation ADC linkers. [ABSTRACT FROM AUTHOR]

Existing antibody–drug conjugate (ADC) linkers, whether cleavable or non‐cleavable, are designed to release highly toxic payloads or payload derivatives upon internalisation of the ADCs into cells. However, clinical studies have shown that only <1 % of the dosed ADCs accumulate in tumour cells. The remaining >99 % of ADCs are nonspecifically distributed in healthy tissue cells, thus inevitably leading to off‐target toxicity. Herein, we describe an intelligent tumour‐specific linker strategy to address these limitations. A tumour‐specific linker is constructed by introducing a hypoxia‐activated azobenzene group as a toxicity controller. We show that this azobenzene‐based linker is non‐cleavable in healthy tissues (O2 >10 %), and the corresponding payload derivative, cysteine‐appended azobenzene‐linker–monomethyl auristatin E (MMAE), can serve as a safe prodrug to mask the toxicity of MMAE (switched off). Upon exposure to the hypoxic tumour microenvironment (O2<1 %), this linker is cleaved to release MMAE and fully restores the high cytotoxicity of the ADC (switched on). Notably, the azobenzene linker‐containing ADC exhibits satisfactory antitumour efficacy in vivo and a larger therapeutic window compared with ADCs containing traditional cleavable or non‐cleavable linkers. Thus, our azobenzene‐based linker sheds new light on the development of next‐generation ADC linkers. [ABSTRACT FROM AUTHOR]

Bystander‐killing payloads can significantly overcome the tumor heterogeneity issue and enhance the clinical potential of antibody‐drug conjugates (ADC), but the rational design and identification of effective bystander warheads constrain the broader implementation of this strategy. Here, graph attention networks (GAT) are constructed for a rational bystander killing scoring model and ADC construction workflow for the first time. To generate efficient bystander‐killing payloads, this model is utilized for score‐directed exatecan derivatives design. Among them, Ed9, the most potent payload with satisfactory permeability and bioactivity, is further used to construct ADC. Through linker optimization and conjugation, novel ADCs are constructed that perform excellent anti‐tumor efficacy and bystander‐killing effect in vivo and in vitro. The optimal conjugate T‐VEd9 exhibited therapeutic efficacy superior to DS‐8201 against heterogeneous tumors. These results demonstrate that the effective scoring approach can pave the way for the discovery of novel ADC with promising bystander payloads to combat tumor heterogeneity. [ABSTRACT FROM AUTHOR]

Aims: The dose‐escalation phase (phase Ia study) of a novel human epidermal growth factor receptor 2 (HER2) antibody–drug conjugate (ADC) FS‐1502 included a dose range from 0.1 to 3.5 mg/kg in HER2‐expressing advanced malignant solid tumours. However, the defined maximum tolerated dose was not reached. This model‐informed approach integrated population pharmacokinetic (PopPK) modelling and exposure–response (E‐R) analysis to facilitate dose selection for phase II. Methods: The PopPK model was constructed using PK data from 109 Chinese patients who received doses of 0.1–3.5 mg/kg FS‐1502 every 3 (Q3W) or 4 weeks during a phase I dose‐escalation and dose expansion trial. The structural model consisted of compartment models for FS‐1502 and unconjugated monomethyl auristatin F. E‐R was explored for the percentage change in tumour size, overall response rate and treatment‐related adverse events. Results: A semi‐mechanistic 2‐analyte PopPK model was developed. The FS‐1502 PK data were best described by a 2‐compartment PK model with parallel linear and nonlinear Michaelis–Menten eliminations. The PK of unconjugated monomethyl auristatin F was described by a 2‐compartment model with first‐order elimination. E‐R analysis supported the clinically meaningful efficacy of FS‐1502 at 2.3 mg/kg and above. However, 2.3 mg/kg Q3W was considered to have a better benefit–risk balance due to a lower incidence of safety events without a significant reduction in efficacy compared to 3.0 mg/kg Q3W. Conclusion: This PopPK and E‐R analysis guided the recommended phase II dose selection of 2.3 mg/kg Q3W and supported body weight‐based dosing for an investigational HER2 ADC FS‐1502. [ABSTRACT FROM AUTHOR]

Receptors are lipid bilayer‐resident molecules that perform a myriad of functions in a cell, from recognition to signaling and solute internalization, and are typically based on proteins. Herein, artificial receptors are engineered based on small organic molecules, toward chemical, non‐genetic engineering of cells. Specifically, artificial internalizing receptors are designed for selective targeting and cell‐specific drug delivery. The artificial receptors are shown to afford nanomolar potency of action for the cognate antibody‐drug conjugates. In the chemically engineered cells, the conjugate activity is at the same time more potent and significantly faster than that observed with the use of the pristine drug. In a mixed cell population, an antibody‐drug conjugate targeted to the artificial receptor can selectively eliminate the chemical receptor‐engineered cells. Taken together, these results illustrate that artificial receptors based on small organic molecules are simple by structure but can mediate one of the foundational cellular functions, namely endocytosis, with excellence. Most importantly, these receptors are truly bio‐orthogonal and thus afford a dedicated route of communication with the chemically engineered cells. [ABSTRACT FROM AUTHOR]

Although cure rates remain low and effective screening strategies are elusive, the recent advances in systemic therapies over the past year highlighted in this review have prolonged survival for women with ovarian cancer. In 2022, the first antibody–drug conjugate for platinum‐resistant ovarian cancer received accelerated US Food and Drug Administration (FDA) approval. Confirmatory studies examining the efficacy of mirvetuximab and other antibody–drug conjugates are underway. In the upfront setting, the first data establishing an overall survival benefit from poly(ADP‐ribose) polymerase inhibitor maintenance was demonstrated after a 7‐year follow‐up period. In contrast, long‐term updates from poly(ADP‐ribose) polymerase inhibitor trials in the noncurative setting reported survival detriments, and the FDA withdrew the respective indications. Several trials attempted to improve upon the standard of care for platinum‐sensitive ovarian carcinoma and those with rare ovarian cancer histologies (carcinosarcoma, clear cell carcinoma) but failed to demonstrate a clinically or statistically meaningful benefit. This leaves the open question of how to further optimize systemic therapy for advanced ovarian carcinoma to improve long‐term survival and cure rates. Recent advances in systemic therapies have prolonged survival for women with ovarian cancer, and 2022 brought accelerated US Food and Drug Administration approval for the first antibody–drug conjugate for platinum‐resistant ovarian cancer and the first data establishing an overall survival benefit from poly(ADP‐ribose) polymerase inhibitor maintenance. However, several trials failed to demonstrate meaningful benefit, and this leaves the open question of how to further optimize systemic therapy for advanced ovarian carcinoma. [ABSTRACT FROM AUTHOR]

The chemical bioconjugation of proteins has seen tremendous applications in the past decades, with the booming of antibody‐drug conjugates and their use in oncology. While genetic engineering has permitted to produce bespoke proteins featuring key (un−)natural amino acid residues poised for site‐selective modifications, the conjugation of native proteins is riddled with selectivity issues. Chemoselective strategies are plentiful and enable the precise modification of virtually any residue with a reactive side‐chain; site‐selective methods are less common and usually most effective on small and medium‐sized proteins. In this context, we studied the application of the Ugi multicomponent reaction for the site‐selective conjugation of amine and carboxylate groups on proteins, and antibodies in particular. Through an in‐depth mechanistic methodology work supported by peptide mapping studies, we managed to develop a set of conditions allowing the highly selective modification of antibodies bearing N‐terminal glutamate and aspartate residues. We demonstrated that this strategy did not alter their affinity toward their target antigen and produced an antibody‐drug conjugate with subnanomolar potency. Excitingly, we showed that the high site selectivity of our strategy was maintained on other protein formats, especially on anticalins, for which directed mutagenesis helped to highlight the key importance of a single lysine residue. [ABSTRACT FROM AUTHOR]

This article discusses the perspectives of patients, industry professionals, and regulatory bodies on optimizing the dosage of antibody-drug conjugates (ADCs) in oncology drug development. Patient perspectives are crucial in dosage optimization, as they can provide valuable information on quality of life, symptoms, and treatment outcomes. The article highlights a patient survey that reveals the importance of cure and improved quality of life for different subtypes of lymphoma. Industry professionals suggest various dosing strategies, such as body weight-based dose capping and response-guided dosing, to improve the benefit-risk profile of ADCs. Regulatory bodies emphasize the need for a wide dose range and investigation of dose schedules in early development to support exposure-response analyses and select optimal doses for registration trials. The article concludes that integrating patient perspectives, innovative study designs, and modeling approaches will be essential in maximizing the efficacy and safety of ADCs. [Extracted from the article]

Extramammary Paget disease (EMPD) is a rare skin cancer mainly found in areas rich in apocrine sweat glands. Since the effective treatments for advanced and/or metastasized EMPD are limited, there is an urgent need to develop novel therapeutic approaches. Nectin cell adhesion molecule 4 (NECTIN4) is highly expressed in cancers and considered to be a promising therapeutic target. NECTIN4 is also expressed in EMPD, but its role and the efficacy of NECTIN4‐targeted therapy in EMPD remain unclear. This study investigated the potential of NECTIN4 as a novel therapeutic target for EMPD. NECTIN4 expression was immunohistochemically analysed in EMPD patients' primary (118 samples) and metastatic (21 samples) lesions. Using an EMPD cell line, KS‐EMPD‐1, the effects of NECTIN4 inhibition on cell proliferation and migration were investigated. NECTIN4 was expressed in primary and metastatic EMPD lesions, and the H‐score of NECTIN4 staining was significantly higher in metastatic lesions than in primary ones. Knockdown of NECTIN4 significantly inhibited cell proliferation and affected cell migration. The cytotoxic effects of NECTIN4‐targeted antibody–drug conjugate (ADC) were further evaluated, revealing a significant decrease in EMPD cell viability. In conclusion, NECTIN4 is a potential therapeutic target and NECTIN4‐targeted ADC is promising as a therapeutic option for EMPD. [ABSTRACT FROM AUTHOR]

Targeted immunotherapies capitalize on the exceptional binding capabilities of antibodies to stimulate a host response that effectuates long‐lived tumor destruction. One example is the conjugation of immunoglobulins (IgGs) to immune effector cells, which equips the cells with the ability to recognize and accurately kill malignant cells through a process called antibody‐dependent cellular cytotoxicity (ADCC). In this study, a chemoenzymatic reaction is developed that specifically functionalizes a single tyrosine (Tyr, Y) residue, Y296, in the Fc domain of therapeutic IgGs. A one‐pot reaction that combines the tyrosinase‐catalyzed oxidation of tyrosine to o‐quinone with a subsequent [3+2] photoaddition with vinyl ether is employed. This reaction installs fluorescent molecules or bioorthogonal groups at Y296 of IgGs or the C‐terminal Y‐tag of an engineered nanobody. The Tyr‐specific reaction is utilized in constructing monofunctionalized antibody‐drug conjugates (ADCs) and antibody/nanobody‐conjugated effector cells, such as natural killer cells or macrophages. These results demonstrate the potential of site‐selective antibody reactions for enhancing targeted cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Aims: Mirvetuximab soravtansine is a first‐in‐class antibody–drug conjugate recently approved for the treatment of folate receptor‐α positive ovarian cancer. The aim of this study was to develop a population pharmacokinetic model to describe the concentration–time profiles of mirvetuximab soravtansine, the payload (DM4) and a metabolite (S‐methyl‐DM4). Methods: Mirvetuximab soravtansine was administered intravenously from 0.15 to 7 mg/kg to 543 patients with predominantly platinum‐resistant ovarian cancer in 3 clinical studies, and the plasma drug concentrations were analysed using a nonlinear mixed‐effects modelling approach. Stepwise covariate modelling was performed to identify covariates. Results: We developed a semi‐mechanistic population pharmacokinetic model that included linear and nonlinear routes for the elimination of mirvetuximab soravtansine and a target compartment for the formation and disposition of the payload and metabolite in tumour cells. The clearance and volume of the central compartment were 0.0153 L/h and 2.63 L for mirvetuximab soravtansine, 8.83 L/h and 3.67 L for DM4, and 2.04 L/h and 6.3 L for S‐methyl‐DM4, respectively. Body weight, serum albumin and age were identified as statistically significant covariates. Exposures in patients with renal or hepatic impairment and who used concomitant cytochrome P450 (CYP) 3A4 inhibitors were estimated. Conclusion: There is no need for dose adjustment due to covariate effects for mirvetuximab soravtansine administered at the recommended dose of 6 mg/kg based on adjusted ideal body weight. Dose adjustment is not required for patients with mild or moderate renal impairment, mild hepatic impairment, or when concomitant weak and moderate CYP3A4 inhibitors are used. [ABSTRACT FROM AUTHOR]

Protein functionalisation for the development of imaging agents and antibody drug conjugates still often relies on statistical amidation of the protein through accessible lysine and cysteine residues, requiring protein to protein conjugation optimisation and can potentially impact the overall function. To combat this, focus has turned to developing proteins that have noncanonical amino acids incorporated into their structure, allowing for site‐specific labelling and functionalisation. Herein we showcase the incorporation of non‐canonical amino acids bearing a tetrazine or azide orthogonal coupling modality into biologics targeted to the prostate‐specific membrane antigen and epidermal growth factor receptor respectively. The placement of these bioorthogonal residues into nanobody or single chain variable fragments (scFvs) is introduced by site‐directed mutagenesis of the protein‐coding DNA that allows for controlled insertion when these proteins are expressed. We show that bioorthogonal coupling of model compounds such as fluorophore or polymeric materials onto the protein does not significantly change the binding affinity, making these protein conjugation methods a powerful tool for development of simple customisable personalised targeted antibody‐drug conjugates where affinity is retained. [ABSTRACT FROM AUTHOR]

Chemically modified proteins have diverse applications; however, conventional chemo‐selective methods often yield heterogeneously labeled products. To address this limitation, site‐specific protein labeling holds significant potential, driving extensive research in this area. Nevertheless, site‐specific modification of native proteins remains challenging owing to the complexity of their functional groups. Therefore, a method for site‐selective labeling of intact proteins is aimed to design. In this study, a novel approach to traceless affinity‐directed intact protein labeling is established, which leverages small binding proteins and genetic code expansion technology. By applying this method, a site‐specific antibody labeling with a drug, which leads to the production of highly effective antibody‐drug conjugates specifically targeting breast cancer cell lines is achieved. This approach enables traceless conjugation of intact target proteins, which is a critical advantage in pharmaceutical applications. Furthermore, small helical binding proteins can be easily engineered for various target proteins, thereby expanding their potential applications in diverse fields. This innovative approach represents a significant advancement in site‐specific modification of native proteins, including antibodies. It also bears immense potential for facilitating the development of therapeutic agents for various diseases. [ABSTRACT FROM AUTHOR]

To replace the conventional maximum tolerated dose (MTD) approach, a paradigm for dose optimization and dose selection that relies on model‐informed drug development (MIDD) approaches has been proposed in oncology. Here, we report our application of an MIDD approach during phase I to inform dose selection for the late‐stage development of datopotamab deruxtecan (Dato‐DXd). Dato‐DXd is a TROP2‐directed antibody‐drug conjugate being developed for advanced/metastatic non‐small cell lung cancer (NSCLC) and other tumors. Data on pharmacokinetics (PKs), efficacy, and safety in NSCLC were collected in the TROPION‐PanTumor01 phase I dose‐expansion and ‐escalation study over a wide dose range of 0.27–10 mg/kg administered every 3 weeks. Population PK and exposure–response analyses were performed iteratively at three data cutoffs to inform dose selection. The 6 mg/kg dose was identified as the optimal dose by the second data cutoff analysis and confirmed by the subsequent third data cutoff analysis. The 6 mg/kg dose was more tolerable (i.e., lower rates of interstitial lung disease, stomatitis, and mucosal inflammation) than the MTD (8 mg/kg) and was more efficacious than 4 mg/kg (simulated mean objective response rate: 23.8% vs. 18.6%; mean hazard ratio of progression‐free survival: 0.74) – a candidate dose studied just below 6 mg/kg. Therefore, the 6 mg/kg dose was judged to afford the optimal benefit–risk balance. This case study demonstrated the utility of an MIDD approach for dose optimization and dose selection. [ABSTRACT FROM AUTHOR]

Aims: ABBV‐3373, an immunology antibody–drug conjugate composed of adalimumab conjugated to a proprietary glucocorticoid receptor modulator (the small‐molecule payload), has the potential to treat immune‐mediated inflammatory diseases. This first‐in‐human study investigated the pharmacokinetics (PK), immunogenicity, pharmacodynamics (PD) using a safety PD marker, and safety/tolerability of ABBV‐3373 in healthy adults. Methods: Fifty‐five participants were randomly assigned to single‐dose subcutaneous (SC; 30, 100 or 300 mg) or intravenous (IV; 30, 300 or 900 mg) ABBV‐3373 or placebo. Eight additional participants received a single dose of 10 mg oral prednisone for evaluation of systemic glucocorticoid effects. Blood samples were collected for up to 85 days postdose for PK, anti‐drug antibody and serum cortisol (safety PD marker) assessments. Results: ABBV‐3373 and total antibody displayed antibody‐like SC/IV PK profiles and the unconjugated/free payload in circulation exhibited formation rate‐limited kinetics with exposure several fold lower than ABBV‐3373 or total antibody. Treatment‐emergent anti‐drug antibody incidence was 69%, with loss of exposure in 6% (SC) and 5% (IV) of participants, but without any impact on safety. ABBV‐3373 up to 300 mg SC/IV had no apparent impact on serum cortisol, and only caused a transient decrease at 900 mg IV. Treatment‐emergent adverse events were primarily mild in severity, and no pattern emerged with respect to dose or route of administration. Conclusions: ABBV‐3373 had favourable PK profiles, manageable immunogenicity, and was generally well‐tolerated. Except for a transient effect at 900 mg IV, there was no apparent impact on serum cortisol. Study results supported further clinical development of ABBV‐3373. [ABSTRACT FROM AUTHOR]

Summary: Very scarce data exist about outcomes of relapsed multiple myeloma patients who have failed proteasome inhibitor, immunomodulatory drug, anti‐CD38 monoclonal antibody and therapies targeting B‐cell maturation antigen (BCMA) (Quad‐class exposed [QCE]). In this retrospective single‐centre study, we determined progression‐free survival (PFS) and overall survival (OS) from anti‐BCMA failure in 45 QCE patients. Seven (16%) patients received antibody‐drug conjugate, 20 (44%) bispecific antibodies and 18 (40%) CAR‐T cell. Thirty patients (67%) received ≥1 subsequent line of treatment. PFS was 4.4 months (95% CI = 2.4–12.5) and OS 6.3 months (95% CI = 3.9–14.4). Having an adverse prognosis, QCE myeloma patients remain an unmet medical need. [ABSTRACT FROM AUTHOR]

Background: Patients with relapsed/refractory multiple myeloma (RRMM) have a high unmet treatment need. Belantamab mafodotin (belamaf), a first‐in‐class, B‐cell maturation antigen‐binding antibody‐drug conjugate, eliminates myeloma cells through direct cell killing and an anti‐myeloma immune response. Methods: DREAMM‐2 (NCT03525678) was a phase 2, two‐arm, open‐label trial in patients with heavily pretreated RRMM who had three or more prior therapies, were refractory to an immunomodulatory agent and a proteasome inhibitor, and refractory or intolerant to an anti‐CD38 monoclonal antibody. Belamaf was given at 2.5 or 3.4 mg/kg every 3 weeks. The primary end point was overall response rate (ORR); secondary end points included progression‐free survival (PFS), overall survival (OS), safety, ocular symptoms, and health‐related quality of life (HRQOL). Results: This final analysis (cutoff date, March 31, 2022), N = 223, with median follow‐up of 12.5 and 13.8 months, demonstrated an ORR of 32% and 35%, median PFS of 2.8 and 3.9 months, and median OS of 15.3 and 14.0 months in the 2.5 mg/kg and 3.4 mg/kg cohorts, respectively. Median duration of response was 12.5 and 6.2 months. No new safety signals were observed; the most common Grade 3 and 4 adverse events were keratopathy (29% vs. 25%), thrombocytopenia (22% vs. 29%), and anemia (21% vs. 28%). HRQOL outcomes suggest that overall global health status/quality of life, physical and role functioning, and overall disease symptoms were maintained or improved during treatment. Conclusions: This final analysis of DREAMM‐2 confirms that in patients with triple‐class refractory RRMM, single‐agent belamaf results in durable and clinically meaningful responses with a manageable safety profile. Although much progress has been made in the treatment landscape for patients with relapsed/refractory multiple myeloma (RRMM), outcomes remain poor once the disease becomes refractory to multiple therapies. The results of the final analysis of the DREAMM‐2 trial further establish that treatment with single‐agent belamaf results in clinically meaningful responses with a manageable safety profile in patients with RRMM who had received at least three previous lines of therapy. [ABSTRACT FROM AUTHOR]

More than half of non‐muscle‐invasive bladder cancer (NMIBC) patients eventually relapse even if treated with surgery and BCG without optional bladder‐preserving therapy. This study aims to investigate the antitumor activity and safety of a HER2‐targeted antibody‐drug conjugate, RC48‐ADC, intravesical instillation for NMIBC treatment. In this preclinical study, it is revealed that human epidermal growth factor receptor 2 (HER2) expression scores of 1+, 2+, and 3+ are recorded for 16.7%, 56.2%, and 14.6% of NMIBC cases. The antitumor effect of RC48‐ADC is positively correlated with HER2 expression in bladder cancer (BCa) cell lines and organoid models. Furthermore, RC48‐ADC is revealed to exert its antitumor effect by inducing G2/M arrest and caspase‐dependent apoptosis. In an orthotopic BCa model, tumor growth is significantly inhibited by intravesical instillation of RC48‐ADC versus disitamab, monomethyl auristatin E, epirubicin, or phosphate‐buffered saline control. The potential toxicity of intravesical RC48‐ADC is also assessed by dose escalation in normal nude mice and revealed that administration of RC48‐ADC by intravesical instillation is safe within the range of effective therapeutic doses. Taken together, RC48‐ADC demonstrates promising antitumor effects and safety with intravesical administration in multiple preclinical models. These findings provide a rational for clinical trials of intravesical RC48‐ADC in NMIBC patients. [ABSTRACT FROM AUTHOR]

This review outlines the latest findings on bioconjugation using lipoic acid ligase A (LplA), a key enzyme that allows the introduction of new functional groups into biomolecules. LplA functions via a characteristic mechanism of covalently binding orthologous lipoic acid derivatives in vivo to a specific 13 amino acid sequence called the LplA acceptor peptide (LAP). This unique functionality has enabled a wide range of applications, including cell‐surface modification, protein immobilization, fluorescent labeling of antibodies. Recently, the modification of proteins without LAP sequences has been demonstrated, suggesting their potential for future biopharmaceutical production. Although several review articles on enzyme ligation have been published, research on LplA remains limited. This review attempts to fill this gap by introducing LplA based on its mechanism, applications, and recent research reports. [ABSTRACT FROM AUTHOR]

Trastuzumab deruxtecan (T‐DXd, DS‐8201a) is an antibody–drug conjugate, comprising an anti‐HER2 antibody at a drug‐to‐antibody ratio of 7–8 with the topoisomerase I inhibitor DXd. In this study, the concentrations of antibody‐conjugated DXd and total antibody were determined and observed to decrease over time following intravenous administration of T‐DXd to monkeys. The drug‐to‐antibody ratio of T‐DXd also decreased in a time‐dependent manner, which reached approximately 2.5 in 21 days after administration. It was suggested that antibody‐conjugated DXd of T‐DXd was relatively stable in vivo compared with that of other reported antibody–drug conjugates. [ABSTRACT FROM AUTHOR]

Belantamab mafodotin, a monomethyl auristatin F (MMAF)–containing monoclonal antibody‐drug conjugate (ADC), demonstrated deep and durable responses in the DRiving Excellence in Approaches to Multiple Myeloma (DREAMM)‐1 and pivotal DREAMM‐2 studies in patients with relapsed/refractory multiple myeloma. As with other MMAF‐containing ADCs, ocular adverse events were observed. To predict the effects of belantamab mafodotin dosing regimens and dose‐modification strategies on efficacy and ocular safety end points, DREAMM‐1 and DREAMM‐2 data across a range of doses were used to develop an integrated simulation framework incorporating two separate longitudinal models and the published population pharmacokinetic model. A concentration‐driven tumor growth inhibition model described the time course of serum M‐protein concentration, a measure of treatment response, whereas a discrete time Markov model described the time course of ocular events graded with the GSK Keratopathy and Visual Acuity scale. Significant covariates included baseline β2‐microglobulin on growth rate, baseline M‐protein on kill rate, extramedullary disease on the effect compartment rate constant, and baseline soluble B cell maturation antigen on maximal effect. Efficacy and safety end points were simulated for various doses with dosing intervals of 1, 3, 6, and 9 weeks and various event‐driven dose‐modification strategies. Simulations predicted that lower doses and longer dosing intervals were associated with lower probability and lower overall time with Grade 3+ and Grade 2+ ocular events compared with the reference regimen (2.5 mg/kg every 3 weeks), with a less‐than‐proportional reduction in efficacy. The predicted improved benefit–risk profiles of certain dosing schedules and dose modifications from this integrated framework has informed trial designs for belantamab mafodotin, supporting dose‐optimization strategies. [ABSTRACT FROM AUTHOR]

Background: The wide use of antibody‐drug conjugates (ADCs) is transforming the cancer‐treatment landscape. Understanding the treatment‐related adverse events (AEs) of ADCs is crucial for their clinical application. We conducted a meta‐analysis to analyze the profile and incidence of AEs related to ADC use in the treatment of solid tumors and hematological malignancies. Methods: We searched the PubMed, Embase, and Cochrane Library databases for articles published from January 2001 to October 2022. The overall profile and incidence of all‐grade and grade ≥ 3 treatment‐related AEs were the primary outcomes of the analysis. Results: A total of 138 trials involving 15,473 patients were included in this study. The overall incidence of any‐grade treatment‐related AEs was 100.0% (95% confidence interval [CI]: 99.9%–100.0%; I2 = 89%) and the incidence of grade ≥ 3 treatment‐related AEs was 6.2% (95% CI: 3.0%–12.4%; I² = 99%). Conclusions: This study provides a comprehensive overview of AEs related to ADCs used for cancer treatment. ADC use resulted in a high incidence of any‐grade AEs but a low incidence of grade ≥ 3 AEs. The AE profiles and incidence differed according to cancer type, ADC type, and ADC components. [ABSTRACT FROM AUTHOR]

Antibody drug conjugates (ADC) are an emerging class of pharmaceuticals consisting of cytotoxic agents covalently attached to an antibody designed to target a specific cancer cell surface molecule followed by internalization and intracellular release of payload to exhibit its anticancer activity. Targeted delivery of cytotoxic payload to a variety of specific cells has been demonstrated to have significant enhancement in clinical efficacy and dramatic reduction in off‐target toxicity. Site‐specific conjugation of payload to the antibody is highly desirable for development of ADC with well‐defined antibody‐to‐drug ratio, enhanced internalization, reduced toxicity, improved stability, desired pharmacological profile and optimal therapeutic index. Here, we reported a site‐specific conjugation strategy for evaluation of antibody internalization and efficacy of ADC designed to target SSEA4 on solid tumors. This strategy stems from the azido‐fucose tag of a homogeneous antibody Fc‐glycan generated via in vitro glycoengineering approach for site‐specific conjugation and optimization of antibody‐drug ratio to exhibit optimal efficacy. The ADC consisting of a chimeric anti‐SSEA4 antibody chMC813‐70, conjugated to the antineoplastic agent monomethyl auristatin E via both cleavable and non‐cleavable linkers showed excellent cytotoxicity profile towards SSEA4‐bearing cancer cells. A clear distinction in cytotoxicity was observed among cancer cells with different SSEA4 expression levels. [ABSTRACT FROM AUTHOR]

Proteolysis Targeting Chimeras (PROTACs) represent a promising therapeutic modality to address undruggable and resistant issues in drug discovery. However, potential on‐target toxicity remains clinically challenging. We developed a generalized caging strategy to synthesize a series of stimuli‐responsive PROTACs (sr‐PROTACs) with diverse molecular blocks bearing robust and cleavable linkers, presenting "turn on" features in manipulating protein degradation. By leveraging pathological cues, such as elevated ROS, phosphatase, H2S, or hypoxia, and external triggers, such as ultraviolet light, X‐Ray, or bioorthogonal reagents, we achieved site‐specific activation and traceless release of original PROTACs through de‐caging and subsequent self‐immolative cleavage, realizing selective uptake and controlled protein degradation in vitro. An in vivo study revealed that two sr‐PROTACs with phosphate‐ and fluorine‐containing cages exhibited high solubility and long plasma exposure, which were specifically activated by tumor overexpressing phosphatase or low dosage of X‐Ray irradiation in situ, leading to efficient protein degradation and potent tumor remission. With more reactive biomarkers to be screened from clinical practice, our caging library could provide a general tool to design activatable PROTACs, prodrugs, antibody‐drug conjugates, and smart biomaterials for personalized treatment, tissue engineering or regenerative medicine. [ABSTRACT FROM AUTHOR]

Proteolysis Targeting Chimeras (PROTACs) represent a promising therapeutic modality to address undruggable and resistant issues in drug discovery. However, potential on‐target toxicity remains clinically challenging. We developed a generalized caging strategy to synthesize a series of stimuli‐responsive PROTACs (sr‐PROTACs) with diverse molecular blocks bearing robust and cleavable linkers, presenting "turn on" features in manipulating protein degradation. By leveraging pathological cues, such as elevated ROS, phosphatase, H2S, or hypoxia, and external triggers, such as ultraviolet light, X‐Ray, or bioorthogonal reagents, we achieved site‐specific activation and traceless release of original PROTACs through de‐caging and subsequent self‐immolative cleavage, realizing selective uptake and controlled protein degradation in vitro. An in vivo study revealed that two sr‐PROTACs with phosphate‐ and fluorine‐containing cages exhibited high solubility and long plasma exposure, which were specifically activated by tumor overexpressing phosphatase or low dosage of X‐Ray irradiation in situ, leading to efficient protein degradation and potent tumor remission. With more reactive biomarkers to be screened from clinical practice, our caging library could provide a general tool to design activatable PROTACs, prodrugs, antibody‐drug conjugates, and smart biomaterials for personalized treatment, tissue engineering or regenerative medicine. [ABSTRACT FROM AUTHOR]

The expansion of the spectrum of human epidermal growth factor receptor 2 (HER2)‐status to HER2‐low, defined as HER2 expression of 1+ by immunohistochemistry (IHC) or 2+ by IHC without gene amplification, has made a major impact in the field of oncology. The HER2‐low expression has emerged as a targetable biomarker, and anti‐HER2 antibody‐drug conjugate trastuzumab deruxtecan has shown significant survival benefit in pretreated metastatic HER2‐low breast cancer (BC). With these recent data, the treatment algorithm for hormone receptor–positive and triple‐negative BC needs to be reconsidered, as approximately half of these BCs are HER2‐low. Although there are different therapeutic agents for hormone receptor–positive and hormone receptor–negative HER2‐low BCs, there is no consensus regarding the sequencing of these agents. In this article, the treatment options for HER2‐low BC are enumerated and a treatment sequencing algorithm based on the current clinical evidence proposed. The expansion of the spectrum of human epidermal growth factor receptor 2 (HER2)‐status to HER2‐low has made a major impact in the field of oncology. Because there is no consensus regarding the sequencing of the HER2‐targeting agents in HER2‐low breast cancers, the treatment options for HER2‐low breast cancer are enumerated and a treatment‐sequencing algorithm based on the current clinical evidence proposed. [ABSTRACT FROM AUTHOR]

The antibody‐drug conjugate (ADC) tisotumab vedotin (TV) received accelerated approval from the US Food and Drug Administration for treatment of adults with recurrent or metastatic cervical cancer (r/mCC) with disease progression on or after chemotherapy. A population pharmacokinetic (PK) model, developed using dosing data from four clinical TV studies, was used to estimate individual exposure and explore safety and efficacy exposure‐response (ER) relationships. Because PK analysis showed no appreciable accumulation of TV and monomethyl auristatin E (MMAE) with repeated dosing, cycle 1 exposure metrics and predicted average concentrations from time zero until end of the cycle in which an event occurred (CavgLast) were used for ER analyses. The probability of achieving objective response increased significantly as the ADC cycle 1 maximum serum concentration (Cmax) increased. The probability of treatment‐related adverse events (AEs) leading to dose modification increased significantly as ADC cycle 1 area under the concentration‐time curve (AUC) increased. Number of grade 2+ ocular AEs increased significantly as ADC cycle 1 AUC, Cmax, and ADC CavgLast increased. MMAE cycle 1 AUC predicted risk of serious treatment‐related AEs. The relationship between ADC exposure and efficacy end points suggests ADC treatment was associated with clinically meaningful response across the observed exposures; greater exposure was associated with increased efficacy. The relationship between ADC and MMAE exposure and safety end points suggests increased exposure was associated with increased AE risk. These results align with clinical findings showing TV 2 mg/kg (≤200 mg for patients ≥100 kg) every 3 weeks is efficacious and tolerable for patients with r/mCC. [ABSTRACT FROM AUTHOR]

Introduction: Antibody‐drug conjugates (ADCs) are a family of therapeutic agents that have demonstrated clinical activity in several indications. Material and methods: In this article, we performed a deep analysis of their clinical landscape matched with public genomic human datasets from tumour antigen targets (TATs), to identify empty areas for clinical development. Results: We observed that TATs used in haematological malignancies were more specific than the ones developed in solid cancers. Those included CD19, CD22, CD30, CD33 and CD79b. In solid tumours, we identified TATs, with approved ADCs, widely expressed in non‐explored niche indications like Enfortumab vedotin (anti‐Nectin4) in lung or cervical cancer; Tisotumab vedotin (anti‐TF) in glioblastoma or pancreatic cancer; and Sacituzumab govitecan (anti‐TROP2) in pancreatic, gastric, thyroid or endometrial cancer, among others. Similarly, niche indications for ADCs in clinical development included targets for CD71, PSMA, PTK7 or CD74, in tumours like breast, lung, stomach or colon. Some of these TATs were essential for the survival of tumour cells like CD71, PSMA and PTK7. Conclusions: In summary, our study opens the door for further evaluation of ADCs in several indications not explored before. [ABSTRACT FROM AUTHOR]

The treatment of implant‐associated bacterial infections and biofilms is an urgent medical need and a grand challenge because biofilms protect bacteria from the immune system and harbor antibiotic‐tolerant persister cells. This need is addressed herein through an engineering of antibody‐drug conjugates (ADCs) that contain an anti‐neoplastic drug mitomycin C, which is also a potent antimicrobial against biofilms. The ADCs designed herein release the conjugated drug without cell entry, via a novel mechanism of drug release which likely involves an interaction of ADC with the thiols on the bacterial cell surface. ADCs targeted toward bacteria are superior by the afforded antimicrobial effects compared to the non‐specific counterpart, in suspension and within biofilms, in vitro, and in an implant‐associated murine osteomyelitis model in vivo. The results are important in developing ADC for a new area of application with a significant translational potential, and in addressing an urgent medical need of designing a treatment of bacterial biofilms. [ABSTRACT FROM AUTHOR]

Efficient and site‐specific modification of native peptides and proteins is desirable for synthesizing antibody‐drug conjugates as well as for constructing chemically modified peptide libraries using genetically encoded platforms such as phage display. In particular, there is much interest in efficient multicyclization of native peptides due to the appeals of multicyclic peptides as therapeutics. However, conventional approaches for multicyclic peptide synthesis require orthogonal protecting groups or non‐proteinogenic clickable handles. Herein, we report a cysteine‐directed proximity‐driven strategy for the constructing bicyclic peptides from simple natural peptide precursors. This linear to bicycle transformation initiates with rapid cysteine labeling, which then triggers proximity‐driven amine‐selective cyclization. This bicyclization proceeds rapidly under physiologic conditions, yielding bicyclic peptides with a Cys‐Lys‐Cys, Lys‐Cys‐Lys or N‐terminus‐Cys‐Cys stapling pattern. We demonstrate the utility and power of this strategy by constructing bicyclic peptides fused to proteins as well as to the M13 phage, paving the way to phage display of novel bicyclic peptide libraries. [ABSTRACT FROM AUTHOR]

Aims: Mesothelin (MSLN) is a cancer‐associated antigen that is overexpressed in malignancies such as mesothelioma, pancreatic and ovarian cancer. It is also a target for novel personalised therapies, including antibodies, antibody–drug conjugates and chimeric antigen receptor T cells. Immunohistochemistry may predict those who would best respond to anti‐mesothelin therapies and guide decisions in therapeutic strategy. This study aimed to assess the intensity and distribution of MSLN immunostaining in mesothelioma, and to determine the prognostic value of MSLN expression by histochemical‐score (H‐score). Methods and results: The MN1 anti‐MSLN antibody was used to stain a formalin‐fixed paraffin‐embedded tissue microarray of histologically confirmed mesothelioma from 75 consecutive patients who had undergone pleurectomy with or without decortication. MSLN positivity, the staining intensity, distribution of staining and H‐score were evaluated. The correlation of H‐score with prognosis was investigated. Sixty‐six per cent of epithelioid tumours were MSLN‐positive (with expression in > 5% tumour cells). Of MSLN‐expressing epithelioid tumours, 70.4% had moderate (2+) or strong (3+) intensity MSLN immunostaining, although only 37% of samples had staining in ≥ 50% of tumour cells. In multivariate analysis, MSLN H‐score as a continuous variable and an H‐score ≥ 33 were independent predictors of improved survival (P = 0.04 and P < 0.001, respectively). Conclusions: MSLN expression was more heterogenous in epithelioid mesothelioma than reported previously. Therefore, it would be appropriate to perform an immunohistochemical assessment of MSLN expression to stratify and assess patient suitability for mesothelin‐targeted personalised therapies, such as chimeric antigen receptor T cells. [ABSTRACT FROM AUTHOR]

Efficient and site‐specific modification of native peptides and proteins is desirable for synthesizing antibody‐drug conjugates as well as for constructing chemically modified peptide libraries using genetically encoded platforms such as phage display. In particular, there is much interest in efficient multicyclization of native peptides due to the appeals of multicyclic peptides as therapeutics. However, conventional approaches for multicyclic peptide synthesis require orthogonal protecting groups or non‐proteinogenic clickable handles. Herein, we report a cysteine‐directed proximity‐driven strategy for the constructing bicyclic peptides from simple natural peptide precursors. This linear to bicycle transformation initiates with rapid cysteine labeling, which then triggers proximity‐driven amine‐selective cyclization. This bicyclization proceeds rapidly under physiologic conditions, yielding bicyclic peptides with a Cys‐Lys‐Cys, Lys‐Cys‐Lys or N‐terminus‐Cys‐Cys stapling pattern. We demonstrate the utility and power of this strategy by constructing bicyclic peptides fused to proteins as well as to the M13 phage, paving the way to phage display of novel bicyclic peptide libraries. [ABSTRACT FROM AUTHOR]

This article discusses the skin toxicity of enfortumab vedotin (EV), an antibody-drug conjugate used to treat urothelial carcinoma. The study found that skin adverse effects were reported in half of the patients, with severe eruptions occurring in 15% of cases. The authors propose a specific management algorithm to help oncologists recognize, classify, and manage skin adverse effects associated with EV use. The algorithm includes recommendations for dermatological consultation, skin biopsy, and the use of topical or oral treatments. The article emphasizes the importance of medical oncologists being well-trained in EV-related dermatological toxicity and highlights the need for a multidisciplinary approach in managing these adverse effects. [Extracted from the article]

Methods for chemical modification of proteins and peptides at certain positions are required for the preparation of antibody‐drug conjugates, protein‐ or peptide‐biotin conjugates, and conjugates used as therapeutics or as tools in biomedical research. We have developed chemical modification methods that use spirooxindole oxirane derivatives for the synthesis of protein‐ and peptide‐conjugates. In most cases, the epoxide group of the spirooxindole oxirane derivatives reacted to form a covalent bond with certain histidine residues and/or the N‐terminal amino group of peptides and proteins. The modification reactions of various proteins resulted in the formation of proteins modified at only one or two positions. [ABSTRACT FROM AUTHOR]

One of the key challenges of improving clinical outcomes of antibody drug conjugates (ADCs) is overcoming cancer resistance to the antibody and/or drug components of ADCs, and hence the need for ADC platforms with high combinatory flexibility. Here, we introduce the use of self‐assembled left‐handed DNA (L–DNA) oligonucleotides to link combinatory single‐domain antibodies and toxin payloads for tunable and adaptive delivery of ADCs. We demonstrate that the method allows convenient construction of a library of ADCs with multi‐specific targeting, multi‐specific payloads, and exact drug‐antibody ratio. The newly constructed ADCs with L–DNA scaffold showed favorable properties of in vitro cell cytotoxicity and in vivo suppression and eradication of solid tumors. Collectively, our data suggest that the L–DNA based modular ADC (MADC) platform is a viable option for generating therapeutic ADCs and for potentially expanding ADC therapeutic window via multi‐specificity. [ABSTRACT FROM AUTHOR]

One of the key challenges of improving clinical outcomes of antibody drug conjugates (ADCs) is overcoming cancer resistance to the antibody and/or drug components of ADCs, and hence the need for ADC platforms with high combinatory flexibility. Here, we introduce the use of self‐assembled left‐handed DNA (L–DNA) oligonucleotides to link combinatory single‐domain antibodies and toxin payloads for tunable and adaptive delivery of ADCs. We demonstrate that the method allows convenient construction of a library of ADCs with multi‐specific targeting, multi‐specific payloads, and exact drug‐antibody ratio. The newly constructed ADCs with L–DNA scaffold showed favorable properties of in vitro cell cytotoxicity and in vivo suppression and eradication of solid tumors. Collectively, our data suggest that the L–DNA based modular ADC (MADC) platform is a viable option for generating therapeutic ADCs and for potentially expanding ADC therapeutic window via multi‐specificity. [ABSTRACT FROM AUTHOR]

Three semimechanistic pharmacokinetic/pharmacodynamic (PK/PD) models, Simeoni, Jumbe, and Hybrid, were used for the efficacy translation of RC88 from preclinical to clinical. RC88 is a mesothelin‐targeting antibody–drug conjugate for malignant solid tumor. In the preclinical study, the relationship between PKs and PDs was determined using the xenograft mouse model derived from ovarian cancer and lung cancer cell lines. A secondary parameter representing the efficacy index of the drug, termed as tumor static concentration (TSC), was calculated using the three semimechanistic PK/PD models. A mechanism‐based target‐mediated drug disposition model was used to predict the human PKs. TSC from mice and predicted human PK were integrated to predict human efficacy dose. Results showed that 2 cell lines were sensitive to drugs, and the predicted efficacy dose was between 0.82 and 1.96 mg/kg q1w. [ABSTRACT FROM AUTHOR]

Although breast cancer has led the way toward precision medicine, more research is still needed to increase curation rates in patients with early disease and to prolong survival with an optimal quality of life in the metastatic setting. Last year, big advances were achieved toward these goals thanks to the significant impact of immunotherapy on survival in triple‐negative breast cancer and the exciting results of antibody‐drug conjugates. Plain Language Summary: The development of new drugs and biomarkers to select those patients who will benefit of them are crucial in improving survival in breast cancer.Last year, the emergence of antibody‐drug conjugates and the reaffirmation of the potential of immunotherapy in breast cancer were the most important findings. The definitive establishment of immunotherapy in triple‐negative breast cancer and the amazing results of the new antibody‐drug conjugates are the main landmarks in 2021 and 2022, and constitute the beginning of a new era in the treatment of breast cancer. [ABSTRACT FROM AUTHOR]

Site‐specific incorporation of multiple distinct noncanonical amino acids (ncAAs) into proteins in mammalian cells is a promising technology, where each ncAA must be assigned to a different orthogonal aminoacyl‐tRNA synthetase (aaRS)/tRNA pair that reads a distinct nonsense codon. Available pairs suppress TGA or TAA codons at a considerably lower efficiency than TAG, limiting the scope of this technology. Here we show that the E. coli tryptophanyl (EcTrp) pair is an excellent TGA‐suppressor in mammalian cells, which can be combined with the three other established pairs to develop three new routes for dual‐ncAA incorporation. Using these platforms, we site‐specifically incorporated two different bioconjugation handles into an antibody with excellent efficiency, and subsequently labeled it with two distinct cytotoxic payloads. Additionally, we combined the EcTrp pair with other pairs to site‐specifically incorporate three distinct ncAAs into a reporter protein in mammalian cells. [ABSTRACT FROM AUTHOR]