Accelerated Discovery of Carbamate Cbl-b Inhibitors Using Generative AI Models and Structure-Based Drug Design.

Casitas B-lymphoma proto-oncogene-b (Cbl-b) is a RING finger E3 ligase that has an important role in effector T cell function, acting as a negative regulator of T cell, natural killer (NK) cell, and B cell activation. A discovery effort toward Cbl-b inhibitors was pursued in which a generative AI design engine, REINVENT, was combined with a medicinal chemistry structure-based design to discover novel inhibitors of Cbl-b. Key to the success of this effort was the evolution of the "Design" phase of the Design-Make-Test-Analyze cycle to involve iterative rounds of an in silico structure-based drug design, strongly guided by physics-based affinity prediction and machine learning DMPK predictive models, prior to selection for synthesis. This led to the accelerated discovery of a potent series of carbamate Cbl-b inhibitors.

Discovery, Optimization, and Biological Evaluation of Arylpyridones as Cbl-b Inhibitors.

Casitas B-lymphoma proto-oncogene-b (Cbl-b), a member of the Cbl family of RING finger E3 ubiquitin ligases, has been demonstrated to play a central role in regulating effector T-cell function. Multiple studies using gene-targeting approaches have provided direct evidence that Cbl-b negatively regulates T, B, and NK cell activation via a ubiquitin-mediated protein modulation. Thus, inhibition of Cbl-b ligase activity can lead to immune activation and has therapeutic potential in immuno-oncology. Herein, we describe the discovery and optimization of an arylpyridone series as Cbl-b inhibitors by structure-based drug discovery to afford compound 31. This compound binds to Cbl-b with an IC50 value of 30 nM and induces IL-2 production in T-cells with an EC50 value of 230 nM. Compound 31 also shows robust intracellular target engagement demonstrated through inhibition of Cbl-b autoubiquitination, inhibition of ubiquitin transfer to ZAP70, and the cellular modulation of phosphorylation of a downstream signal within the TCR axis.

Discovery of a Novel Benzodiazepine Series of Cbl-b Inhibitors for the Enhancement of Antitumor Immunity.

Casitas B-lineage lymphoma proto-oncogene-b (Cbl-b) is a RING finger E3 ligase that is responsible for repressing T-cell, natural killer (NK) cell, and B-cell activation. The robust antitumor activity observed in Cbl-b deficient mice arising from elevated T-cell and NK-cell activity justified our discovery effort toward Cbl-b inhibitors that might show therapeutic promise in immuno-oncology, where activation of the immune system can drive the recognition and killing of cancer cells. We undertook a high-throughput screening campaign followed by structure-enabled optimization to develop a novel benzodiazepine series of potent Cbl-b inhibitors. This series displayed nanomolar levels of biochemical potency, as well as potent T-cell activation. The functional activity of this class of Cbl-b inhibitors was further corroborated with ubiquitin-based cellular assays.

Progress and emerging strategies to preserve function in the treatment of sinonasal cancer.

The sinonasal structures and their adjacent organs host several functions including vision, olfaction, nasal respiration and filtration, secretory immunity, facial expression, articulation, and oral deglutition. We reviewed the current evidence supporting functional preservation in sinonasal cancer treatment. Primary surgery with or without adjuvant modalities continues to be the standard of care for sinonasal cancer. Unfortunately, functional compromise remains a dominant negative feature of this approach. More recently, through advances in therapeutic techniques and improved understanding of the relevant tumor biology, treatments aimed at preserving function and cosmesis are emerging. The evidence for such progress involving minimal access surgery, surgical reconstruction for rehabilitation, new techniques in radiation therapy, inclusion of systemic and locally enhanced chemotherapy, and therapeutic agents based on molecular targets are highlighted. This multi-prong approach bodes well for future patients with sinonasal cancer to undergo successful treatment that includes maximal preservation of associated functions.

A phase IIb, randomised, parallel-group study: the efficacy, safety and tolerability of once-daily umeclidinium in patients with asthma receiving inhaled corticosteroids.

BACKGROUND: Patients with asthma uncontrolled on inhaled corticosteroids may benefit from umeclidinium (UMEC), a long-acting muscarinic antagonist. METHODS: This Phase IIb, double-blind study included patients with reversible, uncontrolled/partially-controlled asthma for ≥6 months, receiving ≥100 mcg/day fluticasone propionate (or equivalent) for ≥12 weeks. Following a 2-week run-in on open-label fluticasone furoate (FF) 100 mcg, patients were randomised (1:1:1) to receive UMEC 31.25 mcg, UMEC 62.5 mcg or placebo on top of FF 100 mcg once-daily for 24 weeks. As-needed salbutamol was provided. Primary and secondary endpoints were change from baseline in clinic trough forced expiratory volume in 1 s (FEV1) and clinic FEV1 3 h post-dose, respectively, at Week 24. Other endpoints included change from baseline in home daily spirometry (trough FEV1, evening FEV1, morning [pre-dose] and evening peak expiratory flow) over 24 weeks. Safety was assessed throughout the study. RESULTS: The intent-to-treat population comprised 421 patients (UMEC 31.25 mcg: n =139, UMEC 62.5 mcg: n =139, placebo: n =143). UMEC 31.25 mcg and 62.5 mcg demonstrated significantly greater improvements from baseline in clinic trough FEV1 at Week 24 (difference [95% CI]: 0.176 L [0.092, 0.260; p<0.001] and 0.184 L [0.101, 0.268; p<0.001], respectively), clinic FEV1 3 h post-dose at Week 24 (0.190 L [0.100, 0.279; p<0.001] and 0.198 L [0.109, 0.287; p<0.001], respectively) and mean change from baseline in daily home spirometry over 24 weeks versus placebo. No new safety signals were identified. CONCLUSIONS: UMEC is a highly effective bronchodilator that leads to improved lung function when administered as a single bronchodilator on top of FF in subjects with fully reversible, uncontrolled/partially-controlled moderate asthma. These data support a favourable benefit/risk profile for UMEC (31.25 mcg and 62.5 mcg). TRIAL REGISTRATION: GSK study ID: 205832; Clinicaltrials.gov ID: NCT03012061.

Depth of invasion alone as an indication for postoperative radiotherapy in small oral squamous cell carcinomas: An International Collaborative Study.

BACKGROUND: We aimed to investigate whether depth of invasion (DOI) should be an independent indication for postoperative radiotherapy (PORT) in small oral squamous cell carcinomas (SCC). METHODS: Retrospective analysis of DOI (<5, 5 to <10, ≥10 mm) and disease-specific survival (DSS) in a multi-institutional international cohort of 1409 patients with oral SCC ≤4 cm in size treated between 1990-2011. RESULTS: In patients without other adverse factors (nodal metastases; close [<5 mm] or involved margins), there was no association between DOI and DSS, with an excellent prognosis irrespective of depth. In the absence of PORT, the 5-year disease-specific mortality was 10% with DOI ≥10 mm, 8% with DOI 5-10 mm, and 6% with DOI <5 mm (P = .169), yielding an absolute risk difference of only 4%. CONCLUSION: The deterioration in prognosis with increasing DOI largely reflects an association with other adverse features. In the absence of these, depth alone should not be an indication for PORT outside a clinical trial.

Phase 2, randomized dose-finding study of tapinarof (GSK2894512 cream) for the treatment of plaque psoriasis.

BACKGROUND: There is a significant need for novel, safe, and efficacious topical treatments for psoriasis. OBJECTIVE: We assessed the safety and efficacy of tapinarof in a new cream formulation at 2 concentrations and with 2 application frequencies in adults with psoriasis. METHODS: Double-blind, vehicle-controlled, randomized, 6-arm trial (1:1:1:1:1:1) in adults, with psoriasis with body surface involvement ≥1% and ≤15% and Physician Global Assessment (PGA) score ≥2 at baseline. Primary endpoint included PGA of 0 or 1 at week 12 and a 2-grade improvement from baseline. Additional analyses included assessment of ≥75% improvement of Psoriasis Area and Severity Index and mean percent change in Psoriasis Area and Severity Index and body surface area involvement. RESULTS: Treatment success defined by PGA 0 or 1 and a 2-grade improvement at week 12 was statistically significantly higher (at a .05 significance level) in the tapinarof groups (65% [1% twice daily], 56% [1% once daily], 46% [0.5% twice daily], and 36% [0.5% once daily]) than in the vehicle groups (11% [twice daily] and 5% [once daily]) and was maintained for 4 weeks posttreatment. Treatment-emergent adverse events were more frequent in patients treated with tapinarof (85/152, 56%) than vehicle (19/75, 25%) and mild-to-moderate in intensity. Severe treatment-emergent adverse events were reported in all tapinarof groups except the 0.5% once daily group. LIMITATIONS: Large confirmation trials are needed. CONCLUSIONS: Tapinarof cream is efficacious and well tolerated in adult patients with psoriasis.

A phase 2, randomized dose-finding study of tapinarof (GSK2894512 cream) for the treatment of atopic dermatitis.

BACKGROUND: Safe and efficacious topical treatments are needed for atopic dermatitis (AD). OBJECTIVE: We assessed the safety and efficacy of tapinarof cream (2 concentrations and 2 application frequencies) in patients with AD. METHODS: A double-blind, vehicle-controlled, randomized, 6-arm trial (1:1:1:1:1:1) in patients age 12 to 65 years, with body surface area involvement of at least 5% to 35% and an Investigator's Global Assessment score of 3 or higher (moderate to severe) at baseline. Primary end points included an Investigator's Global Assessment score of clear or almost clear (0 or 1) and a minimum 2-grade improvement (treatment success) at week 12. Secondary analyses included a 75% or greater improvement in Eczema Area and Severity Index score, reduction of numeric rating scale (NRS) score for itch from baseline, and other prespecified end points. RESULTS: The rates of treatment success with tapinarof cream at week 12 were 53% (a concentration of 1% twice daily), 46% (a concentration of 1% once daily), 37% (a concentration of 0.5% twice daily), 34% (0.5% once daily), 24% (vehicle twice daily), and 28% (vehicle once daily). The rate with a concentration of 1% twice daily (53%) was statistically significantly higher than the rate with vehicle twice daily (24%). Treatment success was maintained for 4 weeks after the end of tapinarof treatment. The rate of treatment-emergent adverse events was higher with tapinarof (93 of 165 [56%]) than with vehicle (34 of 82 [41%]), and the events were mild to moderate in intensity. LIMITATIONS: Large confirmation trials are needed. CONCLUSIONS: Tapinarof cream is efficacious and well tolerated in adolescent and adult patients with AD.

Otolaryngology in Low-Resource Settings: Practical and Ethical Considerations.

Providing otolaryngology care in low-resource settings requires careful preparation to ensure good outcomes. The level of care that can be provided is dictated by available resources and the supplementary equipment, supplies, and personnel brought in. Other challenges include personal health and safety risks as well as cultural and language differences. Studying outcomes will inform future missions. Educating and developing ongoing partnerships with local physicians can lead to sustained improvements in the local health care system.

Discovery of morpholine-based aryl sulfonamides as Nav1.7 inhibitors.

Replacement of the piperidine ring in the lead benzenesulfonamide Nav1.7 inhibitor 1 with a weakly basic morpholine core resulted in a significant reduction in Nav1.7 inhibitory activity, but the activity was restored by shortening the linkage from methyleneoxy to oxygen. These efforts led to a series of morpholine-based aryl sulfonamides as isoform-selective Nav1.7 inhibitors. This report describes the synthesis and SAR of these analogs.

NMR in drug design.

The use of NMR as a tool to determine 3 dimensional protein solution structures, once a darling of the pharmaceutical industry, has largely given way to study of the interaction of prospective drugs with macromolecular targets. Many of these approaches involve ligand-centered studies, which have the advantage of speed and efficiency, but there are also many approaches that take directly from our learnings in macromolecular NMR and provide greater structural detail yet are still optimized for rapid turn-around of information. In the evolution of NMR in the pharmaceutical industry, the unique strengths of NMR to provide dynamic and atomic level information continue to be exploited to discover and design new drugs. Numerous methods have been developed over the past two decades that fall into the categories of fragment-based pre-lead discovery, ligand binding studies and qualitative structural screening.

Peptide Macrocyclization Inspired by Non-Ribosomal Imine Natural Products.

A thermodynamic approach to peptide macrocyclization inspired by the cyclization of non-ribosomal peptide aldehydes is presented. The method provides access to structurally diverse macrocycles by exploiting the reactivity of transient macrocyclic peptide imines toward inter- and intramolecular nucleophiles. Reactions are performed in aqueous media, in the absence of side chain protecting groups, and are tolerant of all proteinogenic functional groups. Macrocyclic products bearing non-native and rigidifying structural motifs, isotopic labels, and a variety of bioorthogonal handles are prepared, along with analogues of four distinct natural products. Structural interrogation of the linear and macrocyclic peptides using variable-temperature NMR and circular dichroism suggests that preorganization of linear substrates is not a prerequisite for macrocyclization.

Development of New Benzenesulfonamides As Potent and Selective Nav1.7 Inhibitors for the Treatment of Pain.

By taking advantage of certain features in piperidine 4, we developed a novel series of cyclohexylamine- and piperidine-based benzenesulfonamides as potent and selective Nav1.7 inhibitors. However, compound 24, one of the early analogs, failed to reduce phase 2 flinching in the mouse formalin test even at a dose of 100 mpk PO due to insufficient dorsal root ganglion (DRG) exposure attributed to poor membrane permeability. Two analogs with improved membrane permeability showed much increased DRG concentrations at doses of 30 mpk PO, but, confoundingly, only one of these was effective in the formalin test. More data are needed to understand the disconnect between efficacy and exposure relationships.

Contextual Role of a Salt Bridge in the Phage P22 Coat Protein I-Domain.

The I-domain is a genetic insertion in the phage P22 coat protein that chaperones its folding and stability. Of 11 acidic residues in the I-domain, seven participate in stabilizing electrostatic interactions with basic residues across elements of secondary structure, fastening the ß-barrel fold. A hydrogen-bonded salt bridge between Asp-302 and His-305 is particularly interesting as Asp-302 is the site of a temperature-sensitive-folding mutation. The pKa of His-305 is raised to 9.0, indicating the salt bridge stabilizes the I-domain by ∼4 kcal/mol. Consistently, urea denaturation experiments indicate the stability of the WT I-domain decreases by 4 kcal/mol between neutral and basic pH. The mutants D302A and H305A remove the pH dependence of stability. The D302A substitution destabilizes the I-domain by 4 kcal/mol, whereas H305A had smaller effects, on the order of 1-2 kcal/mol. The destabilizing effects of D302A are perpetuated in the full-length coat protein as shown by a higher sensitivity to protease digestion, decreased procapsid assembly rates, and impaired phage production in vivo By contrast, the mutants have only minor effects on capsid expansion or stability in vitro The effects of the Asp-302-His-305 salt bridge are thus complex and context-dependent. Substitutions that abolish the salt bridge destabilize coat protein monomers and impair capsid self-assembly, but once capsids are formed the effects of the substitutions are overcome by new quaternary interactions between subunits.

K114 (trans, trans)-bromo-2,5-bis(4-hydroxystyryl)benzene is an efficient detector of cationic amyloid fibrils.

Cationic amyloid fibrils found in human semen enhance the transmission of the human immunodeficiency virus (HIV) and thus, are named semen-derived enhancer of virus infection (SEVI). The mechanism for the enhancement of transmission is not completely understood but it has been proposed that SEVI neutralizes the repulsion that exists between the negatively charged viral envelope and host cell membrane. Consistent with this view, here we show that the fluorescence of cationic thioflavin T (ThT) in the presence of SEVI is weak, and thus ThT is not an efficient detector of SEVI. On the other hand, K114 ((trans, trans)-bromo-2,5-bis(4-hydroxystyryl)benzene) forms a highly fluorescent, phenolate-like species on the cationic surface of SEVI. This species does not form in the presence of amyloid fibrils from insulin and amyloid-ß protein, both of which are efficiently detected by ThT fluorescence. Together, our results show that K114 is an efficient detector of SEVI.

Conformational analysis of thioflavin T bound to the surface of amyloid fibrils.

The interaction of small molecules with the surface of amyloid assemblies is important for the detection and inhibition of amyloid formation. Thioflavin T (ThT), a small molecular rotor, has been used for the detection of amyloid fibrils for over half a century. The basis for detection is simple in that in the presence of fibrils the fluorescence of ThT is dramatically enhanced. The mechanism for this enhancement is not well understood but may depend on the determination of the conformation of ThT bound to the fibril surface. Here, we first use solution-state (1)H NMR to show that the on-off binding of ThT to the surface of insulin amyloid fibrils correlates with the enhancement of ThT fluorescence. We then show that the conformation of surface-bound ThT is twisted. The implications of this result in light of recent experimental and computational studies of the binding of ThT to amyloid or amyloid-like assemblies are discussed.

Curcumin modulates the self-assembly of the islet amyloid polypeptide by disassembling α-helix.

Understanding how small molecules affect amyloid formation is of major biomedical and pharmaceutical importance due to the association of amyloid with incurable diseases including Alzheimer's, Parkinson's, and type II diabetes. Using solution state (1)H NMR, we demonstrate that curcumin, a planar biphenolic compound found in the Indian spice turmeric, delays the self-assembly of islet amyloid polypeptide to NMR-invisible assemblies. Accompanying circular dichroism studies show that curcumin disassembles α-helix in maturing assemblies of IAPP. The amount of α-helix disassembled correlates with predicted and experimentally determined helical content of IAPP obtained by others. Taken together, these results indicate that curcumin modulates IAPP self-assembly by unfolding α-helix on pathway to amyloid. The implications of this work in the elucidation of the mechanism for amyloid formation by IAPP in the presence of curcumin are discussed.

Helix-dipole effects in peptide self-assembly to amyloid.

The formation of amyloid fibrils is associated with incurable diseases including Alzheimer's, Parkinson's, and type 2 diabetes. Important mechanistic details of the self-assembly are unknown partly because of the absence of a clear structural characterization of intermediates. There is experimental evidence, however, for α-helical intermediates that has come primarily from circular dichroism spectroscopy. Here, we strengthen the evidence for helical intermediates by demonstrating helix-dipole effects in the early events of self-assembly. Previously, we showed that capped peptides containing the part of the islet amyloid polypeptide that may be responsible for the initial intermolecular contacts (Acetyl-R(11)LANFLVHSSNNFGA(25)-NH(2) and Acetyl-R(11)LANFLVHSGNNFGA(25)-NH(2) which contains the S20G mutation associated with early onset type 2 diabetes) self-assemble via helical intermediates [Liu et al. (2010) J. Am. Chem. Soc.132, 18223-18232]. We demonstrate here that when the peptides are uncapped, they do not self-assemble as indicated primarily by circular dichroism and nuclear magnetic resonance data. Self-assembly is restored when the charge on α-NH(3)(+) of Arg11 is eliminated but not when the charge on α-COO(-) of Ala25 is removed, consistent with the helicity of the peptides skewed toward the N-terminus. Our results strengthen the hypothesis that α-helical intermediates are on pathway to amyloid formation and indicate that the helix dipole is an attractive target for inhibiting the formation of α-helical assemblies.

Kinetic profile of amyloid formation in the presence of an aromatic inhibitor by nuclear magnetic resonance.

The self-assembly of amyloid proteins into ß-sheet rich assemblies is associated with human amyloidoses including Alzheimer's disease, Parkinson's disease, and type 2 diabetes. An attractive therapeutic strategy therefore is to develop small molecules that would inhibit protein self-assembly. Natural polyphenols are potential inhibitors of ß-sheet formation. How these compounds affect the kinetics of self-assembly studied by thioflavin T (ThT) fluorescence is not understood primarily because their presence interferes with ThT fluorescence. Here, we show that by plotting peak intensities from nuclear magnetic resonance (NMR) against incubation time, kinetic profiles in the presence of the polyphenol can be obtained from which kinetic parameters of self-assembly can be easily determined. In applying this technique to the self-assembly of the islet amyloid polypeptide in the presence of curcumin, a biphenolic compound found in turmeric, we show that the kinetic profile is atypical in that it shows a prenucleation period during which there is no observable decrease in NMR peak intensities.