Search Results (280)

Background/Objectives: Covalent inhibitors often demonstrate prolonged pharmacological effects even after their disappearance from the site of action because target recovery depends on target turnover. This disconnect between pharmacokinetics (PK) and pharmacodynamics (PD) complicates the development of such inhibitors since plasma exposure coverage of in vitro potency cannot be used for compound selection and human dose projections. In this study, we describe the development of a PK/PD modeling framework for covalent inhibitors. Methods: The model was developed for KRAS G12C inhibitors using pre-clinical data on sotorasib. The model was validated using data from both internal Amgen compounds and published data for several KRAS G12C inhibitors. The applicability of the framework was extended to EGFR covalent inhibitors by incorporating PK/PD and the efficacy of osimertinib and its active metabolite AZ5104. Results: The model successfully captured the pharmacokinetics, KRAS G12C target occupancy, inhibition of phosphorylation of ERK protein, and tumor growth inhibition following the administration of sotorasib in mice bearing MIA PaCa-2 xenografts. External validation with several internal Amgen compounds as well as publicly available data on KRAS G12C inhibitors showed the robustness of the model. The application of this framework to EGFR inhibitor Osimertinib and AZ5104 captured p-EGFR dynamics and resultant tumor growth inhibition. Conclusions: A modeling framework for covalent inhibitors was developed that links exposure to target occupancy, downstream signaling, and tumor efficacy. This framework could be useful for compound optimization and human dose projections. Full article

Chronic spontaneous urticaria (CSU) is a mast cell-driven disorder defined by recurrent wheals, angioedema, or both, persisting for longer than six weeks without an identifiable external trigger. Second-generation H1-antihistamines remain first-line therapy, yet a large share of patients stay symptomatic after the dose is raised up to fourfold, and for more than a decade, omalizumab was the only targeted option for those who failed antihistamines. This began to change in 2025, when the interleukin-4 receptor alpha (IL-4Rα) antagonist dupilumab and the oral, covalent Bruton tyrosine kinase (BTK) inhibitor remibrutinib were approved for antihistamine-refractory CSU within months of one another, while the anti-KIT monoclonal antibody barzolvolimab, which depletes mast cells, advanced into the largest phase 3 program the disease has seen. This narrative review outlines the guideline framework that still anchors CSU care, appraises the pivotal efficacy and safety data for omalizumab, dupilumab, remibrutinib, and barzolvolimab, and considers how these mechanistically distinct agents might be positioned and sequenced. The widening choice makes individualized, mechanism-informed treatment a realistic goal, but it also sharpens unresolved questions about patient selection, optimal treatment duration in a naturally remitting disease, and the long-term safety of newer oral and mast cell-depleting approaches. Full article

The use of covalent warheads targeting the catalytic cysteine has been a cornerstone in the coronavirus main protease (M^pro) inhibitor development. Various electrophilic motifs have been explored, including aldehydes, nitriles, ketoamides, and hydroxymethyl ketones (HMKs). Recent efforts have mostly centered around nitrile warheads, given the success of Nirmatrelvir in the clinic. However, it is essential to identify and develop alternative chemotypes with distinct chemical and pharmacological profiles to prepare for future pandemics. Among such alternatives, HMKs are of particular interest because they balance reduced intrinsic electrophilicity with an excellent selectivity profile. Nevertheless, early HMK-based compounds, such as the clinical-stage M^pro inhibitor PF-00835231, suffered from poor oral bioavailability and therefore required intravenous administration, with or without prodrug derivatization of the hydroxyl group. In this work, we describe our efforts to advance the HMK field by discovering mCMX110, a lead compound that exhibits superior potency, increased unbound exposure in vivo, and favorable oral bioavailability in preclinical studies. Full article

KRAS G12C, long considered an undruggable oncogenic driver, has become one of the most consequential therapeutic targets in non-small cell lung cancer (NSCLC). The discovery of a cryptic binding pocket accessible in the GDP-bound state enabled covalent inhibitors—sotorasib and adagrasib—that have received regulatory approval for previously treated KRAS G12C-mutant NSCLC, with sotorasib demonstrating PFS and OS superiority over docetaxel in CodeBreaK 200 and adagrasib showing meaningful intracranial activity and a progression-free survival benefit over docetaxel in KRYSTAL-12. Yet response durability is limited by on-target switch-II pocket mutations, upstream RTK and SHP2-mediated bypass signaling, downstream MAPK and PI3K-AKT reactivation, phenotypic plasticity, and adverse modulation by co-occurring STK11, KEAP1, and TP53 alterations. Next-generation covalent inhibitors (divarasib, glecirasib, olomorasib), tri-complex RAS(ON) inhibitors (RMC-6291), pan-KRAS agents, and rationally designed combinations with EGFR, SHP2, SOS1, and PD-1 inhibitors are repositioning KRAS-directed therapy toward earlier lines of treatment. This review integrates the structural, signaling, and clinical biology of KRAS G12C with contemporary trial and real-world evidence to examine the emerging case for first-line KRAS G12C inhibition in genomically defined subsets of NSCLC. First-line use nonetheless remains investigational; platinum-based chemoimmunotherapy remains the standard of care outside of clinical trials, and a frontline indication will require confirmation from randomized phase III trials. Full article

With a lifetime risk estimated to be 1 in 8 in industrialized countries, breast cancer is the most frequent type of cancer among women worldwide and the second leading cause of cancer deaths in women. More importantly, current evidence suggests that in women aged <45 years, breast cancer is unquestionably the leading cause of cancer-related deaths. Hormonal therapy has an established role in the treatment of breast cancer. Hormonal therapy aims at preventing the stimulation of mitogenic estrogen-dependent pathways. Hormonal therapy can be performed through blocking the production of estrogens or through blocking the action of estrogens upon tumor cells. The action of estrogens upon tumor cells can be blocked through selective estrogen receptor modulators (SERMs) or through selective estrogen receptor downregulators (SERDs). Estrogen receptor mutation (ESR1 mutation) is one of the common mechanisms by which breast cancer becomes resistant to additional therapies from SERMs or aromatase inhibitors. Fulvestrant, an injectable anti-estrogen, is the SERD commonly used. Fulvestrant has no agonistic activity and causes degradation of the estrogen receptor. This agent is more active in postmenopause than premenopause and is indicated in the treatment of advanced breast cancer in case of disease progression during or after tamoxifen. Oral SERDs are being rapidly developed to replace fulvestrant with the potential of higher efficacy and lower toxicities. Novel agents such as complete estrogen receptor antagonists (CERANs), proteolysis targeting chimeras (PROTACs), and selective estrogen receptor covalent antagonists (SERCAs) are also promising therapies. This manuscript focuses on recent advances in the development of drugs targeting the estrogen receptor. Full article

For nearly a century, since the discovery of penicillin by Alexander Fleming, we have used covalent inhibitors as antimicrobial drugs. The success of penicillin in treating microbial infections led to numerous other antibiotics containing β-lactam, the reactive warhead that forms the covalent adduct, exemplified by later-generation cephalosporins with approvals into 2020. In parallel, early non-β-lactam covalent agents also emerged, extending covalent mechanisms beyond β-lactam antibacterials to antifungal, antiparasitic, and antiviral applications. Despite the successes of covalent mechanisms of action, there are still considerable safety concerns due to the possibility of off-target covalent adducts which may lead to significant side effects. This review provides an overview of non-β-lactam covalent antimicrobials across all major pathogen classes, organized by their warhead class, covalency, and resistance mechanisms, and outlines design and clinical-level mitigation strategies. We trace the field from the serendipitous discovery of penicillin to the intentional design of new drugs, with a discussion of changes in perception and evolution of technology that enable modern covalent drug design. Full article

Non-Hodgkin lymphoma (NHL) encompasses a biologically diverse group of malignancies for which the integration of precision medicine has markedly reshaped therapeutic strategies. Recent advances in molecular profiling, target identification, and drug development have led to the introduction of highly selective agents capable of overcoming resistance mechanisms and improving outcomes in relapsed or refractory disease. This review highlights three targeted therapies—pirtobrutinib, brentuximab vedotin, and belinostat—and their evolving roles in modern NHL management. Pirtobrutinib, a next-generation, non-covalent Bruton tyrosine kinase (BTK) inhibitor, demonstrates preserved activity in patients previously treated with covalent BTK inhibitors (BTKi), addressing a critical unmet need in B-cell lymphomas. Brentuximab vedotin, an antibody–drug conjugate targeting CD30, has significantly improved therapeutic precision by delivering cytotoxic agents directly to lymphoma cells and has become a central component of treatment for CD30-expressing NHL subtypes. Belinostat, a broad-spectrum histone deacetylase (HDAC) inhibitor, offers a mechanistically distinct epigenetic approach, particularly in peripheral T-cell lymphomas (PTCL), where conventional chemotherapy has limited efficacy. Together, these agents exemplify three complementary paradigms of precision oncology in NHL: kinase signaling inhibition, antigen-directed cytotoxic delivery, and epigenetic modulation. This review synthesizes current evidence, clinical trial data, and future perspectives regarding the integration of pirtobrutinib, brentuximab vedotin, and belinostat into evolving treatment paradigms. Cumulatively, these therapies illustrate both the progress and the ongoing challenges of biomarker-driven treatment in NHL, including resistance mechanisms, toxicity management, optimal therapeutic sequencing, and variability in evidence maturity across targeted strategies. While pirtobrutinib and brentuximab vedotin are supported by increasingly robust clinical evidence in selected lymphoma subtypes, the role of belinostat remains constrained by modest response rates and limited randomized data, underscoring the continued need for biomarker refinement and more precisely individualized therapeutic approaches in NHL precision medicine. Full article

Gram-positive bacteria covalently anchor specific proteins to the peptidoglycan cell wall via sortase, a cysteine transpeptidase that targets proteins with a cell wall sorting signal. Sortase enzymes are critical for bacterial pathogenesis, and their inhibitors have become promising therapeutic targets for infection management. Filifactor alocis, a Gram-positive anaerobic bacterium, is now proposed as a diagnostic indicator of periodontal disease. Unlike other bacteria, F. alocis encodes a single putative sortase, FA1364. In this study, we functionally characterized the putative sortase FA1364 and found that it belongs to the class A family (SrtA). The SrtA-anchored surface proteins (FA1006, FA1336, FA1424, and FA1750) were identified, and MS/MS analysis confirmed that SrtA is required for their cell-surface localization. The recombinant SrtA protein could recognize and cleave the LPKTG sorting motif with cysteine 191 and arginine 200 as essential catalytic residues. F. alocis FLL101 (ΔFA1364::ermF) showed reduced ability to coaggregate and form biofilm, along with decreased collagen binding and survival in epithelial cells. Additionally, the FA1364-defective mutant exhibited increased sensitivity to air exposure. Collectively, these results suggest that the F. alocis SrtA protein is an important virulence factor and may represent a novel therapeutic target for the control of periodontal diseases. Full article

Bruton’s tyrosine kinase (BTK) inhibitors have revolutionized B-cell malignancy treatment but paradoxically increase infection susceptibility. Covalent BTK inhibitors (Ibrutinib, Acalabrutinib, Zanubrutinib) induce sustained BTK blockade but disrupt immune homeostasis through off-target effects on T-cell and myeloid signaling, contributing to hypogammaglobulinemia and increased risk of bacterial, viral, and opportunistic fungal infections. Non-covalent inhibitors (Pirtobrutinib) and emerging BTK degraders offer more selective inhibition, preserving T-cell function and potentially mitigating infection risk, though their long-term immunological impact requires further study. Infection susceptibility varies across BTK inhibitor generations, reflecting differences in kinase selectivity, modulation of humoral and cellular immunity, and disease-intrinsic immune dysfunction in chronic lymphocytic leukemia. This review examines the mechanistic basis of BTK inhibitor-associated immune dysfunction, compares generational differences in selectivity and safety profiles, and provides evidence-based recommendations for infection risk mitigation in clinical practice. Full article

Background/Objectives: Acute myeloid leukemia (AML) remains in need of more broadly effective therapeutic strategies. THZ1, a covalent CDK7 inhibitor, has shown anti-leukemic activity in AML, but the mechanism underlying its response remains incompletely defined. This study aimed to identify key modulators and related transcriptional programs involved in THZ1 response in AML. Methods: We combined a genome-wide CRISPR/Cas9 screen with functional validation and transcriptomic analyses. Results: TP53 was the top positively selected gene in the CRISPR screen in MOLM-13 cells. THZ1 induced p53 accumulation, and pharmacologic activation of the p53 pathway with idasanutlin further enhanced the early anti-leukemic response to THZ1 at 24 h. TP53 loss reduced the sensitivity of AML cells to THZ1-induced apoptosis, but did not abolish THZ1 responsiveness. Transcriptomic analyses showed that TP53 loss substantially reshaped the transcriptional state, whereas MYC and E2F target programs remained the most consistent pathways linked to THZ1 response. THZ1 also continued to suppress these programs in TP53-knockout MOLM-13 cells and TP53-mutant THP-1 cells. Conclusions: Overall, TP53 contributes to the anti-leukemic response to THZ1 but does not determine it, and THZ1 continues to suppress MYC and E2F target programs after TP53 loss. Full article

Background: Cancer cells exhibit metabolic reprogramming characterized by increased dependence on glutamine to sustain rapid proliferation and biosynthetic demands. Kidney-type glutaminase (KGA), which catalyzes the first and rate-limiting step of glutamine metabolism, represents a promising therapeutic target, particularly in triple-negative breast cancer (TNBC), an aggressive sub-type lacking effective targeted therapies. This study evaluated 2-amino-4-boronobutyric acid (ABBA), a boronic acid-containing glutamine analog, as a potential KGA inhibitor with anticancer activity. Methods: KGA inhibition was assessed using a fluorometric enzymatic assay. Cytotoxic effects were examined in multiple TNBC cell lines. Covalent docking and molecular simulation analysis were performed to characterize interactions between ABBA and the KGA active site. Results: ABBA potently inhibited KGA activity, with an IC₅₀ of approximately 1.0 μM, demonstrating greater efficacy than several non-proteinogenic amino acid analogs. ABBA induced dose-dependent cytotoxicity across multiple TNBC cell lines, with pronounced sensitivity observed in basal sub-type cells and cellular sensitivity correlated with KGA expression levels. Expression of γ-glutamyl transpeptidase 1 (GGT1) was negligible, and, excluding any off-target effects, the observed anticancer effects are primarily attributed to KGA inhibition. Docking analysis indicated that ABBA forms a reversible covalent adduct with the catalytic Ser286 residue of KGA in a boronate tetrahedral geometry resembling transition-state mimics, while molecular simulation demonstrated stabilization of the complex through hydrogen bonding and electrostatic interactions. Conclusions: ABBA is a potent boron-based glutaminase inhibitor with therapeutic potential for targeting glutamine metabolism in TNBC. Further structural optimization and in vivo evaluation are warranted to advance ABBA toward therapeutic development. Full article

This review offers a critical and comprehensive overview of the most promising covalent inhibitors against traditional and emerging enzymatic targets of Mycobacterium tuberculosis (Mtb). Nearly three decades after the World Health Organisation’s (WHO) declaration of tuberculosis (TB) as a global health emergency, Mtb continues to claim millions of lives, remaining among the leading causes of death worldwide. In recent years, several efforts have been devoted to shortening and improving treatment outcomes and to overcoming increasing drug resistance. The aim of our work is to provide a perspective on recent progress in the field of covalent inhibitors of mycobacterial enzymes, highlighting the current landscape and outlining future directions for safer and more effective strategies. Full article

Background/Objectives: KRAS G12C mutations define a clinically actionable subset of solid tumors, particularly non–small cell lung cancer. Clinical responses to approved covalent inhibitors remain limited by intrinsic and acquired resistance, highlighting the need for structurally distinct inhibitor scaffolds to expand therapeutic options. The objective of this study was to identify novel covalent binders targeting the KRAS G12C switch-II pocket through large-scale in silico screening and experimental validation. Methods: More than 1.9 million small molecules from diverse commercial libraries were screened using covalent docking, followed by multi-stage refinement incorporating molecular dynamics simulations, MM/GBSA free-energy estimation, and cancer-focused QSAR modeling. Results: This integrated workflow yielded 50 prioritized compounds spanning several chemically distinct scaffold classes. These candidates displayed favorable predicted binding energetics, stable ligand-protein interactions over extended simulation timescales, and low structural similarity to clinically approved KRAS G12C inhibitors sotorasib and adagrasib. Benchmarking against these clinical agents, using identical computational parameters, yielded comparable predicted binding energies for several candidate molecules. In cellular NanoBRET target-engagement assays, selected scaffolds, including K788-7251 and AN-989/14669131, exhibited sub-micromolar engagement of KRAS G12C with minimal endothelial cytotoxicity. Conclusions: Collectively, these findings identify structurally distinct, KRAS G12C inhibitor chemotypes and provide tractable starting points for the development of next-generation targeted therapies. Full article

Cancer therapies are increasingly reliant on immunotherapeutic interventions; however, the persistent emergence of primary, adaptive, and acquired resistance severely limits durable clinical efficacy. Circular RNAs (circRNAs), distinguished by their extreme structural stability and covalently closed loops, have recently been established as potent orchestrators of this immune evasion. This review systematically synthesizes current advancements detailing how circRNAs undermine anti-tumor immunity across diverse malignancies. Specifically, we delineate their critical roles in post-transcriptionally upregulating immune checkpoint molecules (e.g., PD-L1), mediating intercellular immunosuppression via exosomal transfer, and metabolically reprogramming the tumor microenvironment to drive CD8+ T-cell exhaustion and macrophage polarization. Ultimately, we conclude that translating these molecular insights into clinical practice is paramount. Beyond serving as predictive biomarkers, engineering circRNA-targeted therapies and exploiting tumor-specific circRNAs to develop novel anti-tumor vaccines represent essential, paradigm-shifting strategies to definitively overcome immune checkpoint inhibitor resistance. Full article

Obesity represents one of the most critical global public health challenges. Pancreatic lipase (PL) serves as a key therapeutic target for obesity control, whereas clinical synthetic PL inhibitors are greatly restricted by adverse reactions. Traditional Chinese medicines (TCMs) have a long-standing history in regulating lipid metabolism and ameliorating obesity-related disorders, and are characterized by remarkable structural diversity, low toxicity, and mild side effects, thus representing a promising source for developing safe and efficient PL inhibitors. In this work, an integrated strategy combining in silico screening and in vitro validation was employed to identify potential PL inhibitors from TCM components, including molecular docking, molecular dynamics simulation, MM/PBSA binding free energy computation, and in vitro enzymatic assay. Six compounds with docking scores ranging from −9.9 to −9.0 kcal/mol were selected for further investigation. Molecular dynamics simulations verified the favorable structural stability of the corresponding ligand–PL complexes, and MM/PBSA calculations demonstrated negative binding free energies from −21.24 ± 0.39 to −12.03 ± 0.40 kcal/mol. In vitro experiments indicated that three compounds (Hydroxygenkwanin, Atractylenolide I, and Peiminine) showed effective PL inhibitory activity, with IC₅₀ values of 0.128 ± 0.009, 0.584 ± 0.031, and 0.748 ± 0.042 mM, respectively. These values are comparable to quercetin (0.231 ± 0.034 mM) but significantly higher than orlistat (0.481 ± 0.023 μM), which is attributed to their non-covalent binding pattern. Collectively, this study validated the reliability of the integrated in silico and in vitro screening strategy, identified three effective pancreatic lipase inhibitors derived from TCMs, established a robust paradigm for the discovery of natural PL inhibitors, and laid a solid foundation for subsequent research on natural anti-obesity agents. Full article