Safety, pharmacokinetics, and pharmacodynamics of BMS-986142, a novel reversible BTK inhibitor, in healthy participants

Synthesis and biological evaluation of novel 3,6- amide and thioamide substituted- 2,3,4,9-tetrahydro-1H-carbazoles for anti-cancer activity

Herein, we report the synthesis of new compounds with demonstrated anticancer properties based on the 2,3,4,9-tetrahydro-1H-carbazole scaffold. The Fischer indolization method was used to close the heterocyclic motif. The synthesis method's scope and limitations were thoroughly assessed through a series of experiments. Biological assays revealed that two thioamide compounds exhibited significant anticancer activity against MCF-7, HTC116, and A596 cell lines. Comprehensive in vitro profiling included evaluation of cell cytotoxicity, morphological alterations, colony formation and cell adhesion in 3D cultures, cell cycle analysis, DNA damage induction, impact on mitochondria, and apoptosis. Ex ovo studies further demonstrated these compounds' potential to inhibit angiogenic processes. Our results indicate that the newly developed compounds activate processes leading to DNA damage and disruption of mitochondrial function.

Therapeutic potential and recent progression of BTK inhibitors against rheumatoid arthritis

Rheumatoid arthritis (RA) is a complex chronic inflammatory illness that affects the entire physiology of human body. It has become one of the top causes of disability worldwide. The development and progression of RA involves a complex interplay between an individual's genetic background and various environmental factors. In order to effectively manage RA, a multidisciplinary approach is required, as this disease is complicated and its pathophysiological mechanism is not fully understood yet. In majority of arthritis patients, the presence of abnormal B cells and autoantibodies, primarily anti-citrullinated peptide antibodies and rheumatoid factor affects the progression of RA. Therefore, drugs targeting B cells have now become a hot topic in the treatment of RA which is quite evident from the recent trends seen in the discovery of various B cell receptors (BCRs) targeting agents. Bruton's tyrosine kinase (BTK) is one of these recent targets which play a role in the upstream phase of BCR signalling. BTK is an important enzyme that regulates the survival, proliferation, activation and differentiation of B-lineage cells by preventing BCR activation, FC-receptor signalling and osteoclast development. Several BTK inhibitors have been found to be effective against RA during the in vitro and in vivo studies conducted using diverse animal models. This review focuses on BTK inhibition mechanism and its possible impact on immune-mediated disease, along with the types of RA currently being investigated, preclinical and clinical studies and future prospective.

Discovery and Preclinical Characterization of BIIB129, a Covalent, Selective, and Brain-Penetrant BTK Inhibitor for the Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic disease with an underlying pathology characterized by inflammation-driven neuronal loss, axonal injury, and demyelination. Bruton's tyrosine kinase (BTK), a nonreceptor tyrosine kinase and member of the TEC family of kinases, is involved in the regulation, migration, and functional activation of B cells and myeloid cells in the periphery and the central nervous system (CNS), cell types which are deemed central to the pathology contributing to disease progression in MS patients. Herein, we describe the discovery of BIIB129 (25), a structurally distinct and brain-penetrant targeted covalent inhibitor (TCI) of BTK with an unprecedented binding mode responsible for its high kinome selectivity. BIIB129 (25) demonstrated efficacy in disease-relevant preclinical in vivo models of B cell proliferation in the CNS, exhibits a favorable safety profile suitable for clinical development as an immunomodulating therapy for MS, and has a low projected total human daily dose.

Evaluation of BMS-986142, a reversible Bruton's tyrosine kinase inhibitor, for the treatment of rheumatoid arthritis: a phase 2, randomised, double-blind, dose-ranging, placebo-controlled, adaptive design study

BACKGROUND

Bruton's tyrosine kinase (BTK) is a promising biological target for rheumatoid arthritis treatment. This study examined safety, efficacy, and pharmacokinetics of BMS-986142, an oral, reversible BTK inhibitor. The aim was to compare the efficacy of BMS-986142 with placebo on a background of methotrexate in patients with moderate-to-severe rheumatoid arthritis and inadequate response to methotrexate.

METHODS

This phase 2, randomised, double-blind, dose-ranging, placebo-controlled, adaptive design study was conducted across 14 countries and 79 clinical sites. We recruited people aged 18 years or older with a documented diagnosis of rheumatoid arthritis at least 16 weeks before screening with an inadequate response to methotrexate with or without inadequate response to up to two tumour necrosis factor inhibitors. Participants were randomly assigned (1:1:1:1) to oral BMS-986142 (100 mg, 200 mg, or 350 mg) or placebo once daily for 12 weeks. Randomisation was done using an interactive voice response system and stratified by prior treatment status and geographical region. All participants, care providers, investigators, and outcome assessors were masked to treatment allocation. Co-primary endpoints were 20% and 70% improvement in American College of Rheumatology criteria (ACR20 and ACR70) at week 12. Primary endpoints were assessed in the efficacy analysis population (all randomised patients who received at least one dose of the study drug and did not discontinue the study). Safety endpoints were analysed in the as-treated analysis population, which included all patients who received at least one dose of the study drug (patients were grouped according to the treatment they actually received vs the treatment to which they were randomised). This trial was registered with ClinicalTrials.gov, number NCT02638948.

FINDINGS

Between Feb 24, 2016 and May 3, 2018, 248 patients were randomised (73 in the BMS-986142 100 mg group, 73 in the 200 mg group, 26 in the 350 mg group, and 75 in the placebo group; one post-randomisation exclusion); mean age was 56·7 years (SD 12·7); 214 (87%) of 247 were women, 33 (13%) were men, and 188 (76%) were White. Pre-specified interim analysis resulted in discontinuation of the 350 mg BMS-986142 dose due to elevated liver enzymes and absence of benefit versus placebo. Co-primary endpoints were not met. Response rates for ACR20 (placebo: 23 [31%] of 75; 100 mg: 26 [36%] of 73; 200 mg: 31 [42%] of 73) and ACR70 (placebo: three [4%] of 75; 100 mg: three [4%] of 73; 200 mg: seven [10%] of 73) were not significantly different to placebo; estimate of difference versus placebo for ACR20 was 4·9 (95% CI -10·2 to 20·1; p=0·52) for 100 mg and 11·8 (-3·6 to 27·2; p=0·14) for 200 mg, and for ACR70 the estimate of difference was 0·1 (-16·0 to 16·5; nominal p=1·00) for 100 mg and 5·6 (-10·5 to 21·9; nominal p=0·21) for 200 mg. Six patients experienced serious adverse events (four in the placebo group [mouth ulceration, open globe injury, rheumatoid arthritis flare, and endometrial adenocarcinoma] and two in the BMS-986142 100 mg group [angina pectoris and intestinal obstruction]); there were no deaths.

INTERPRETATION

Further investigation of BMS-986142 in people with rheumatoid arthritis is not warranted. An absence of clinical benefit in this study, together with other study results, highlights the need for additional research on the extent of BTK inhibition, treatment duration, and adequacy of drug distribution to inflammation sites, to understand the potential utility of BTK inhibition as a therapeutic strategy for rheumatoid arthritis.

FUNDING

Bristol Myers Squibb.

Synthesis of 3-(Pyridin-2-yl)quinazolin-2,4(1H,3H)-diones via Annulation of Anthranilic Esters with N-pyridyl Ureas

A new route for the synthesis of quinazolin-2,4(1H,3H)-diones and thieno [2,3-d]pyrimidine-2,4(1H,3H)-diones substituted by pyridyl/quinolinyl moiety in position 3 has been developed. The proposed method concluded in an annulation of substituted anthranilic esters or 2-aminothiophene-3-carboxylates with 1,1-dimethyl-3-(pyridin-2-yl) ureas. The process consists of the formation of N-aryl-N'-pyridyl ureas followed by their cyclocondensation into the corresponding fused heterocycles. The reaction does not require the use of metal catalysts and proceeds with moderate to good yields (up to 89%). The scope of the method is more than 30 examples, including compounds with both electron-withdrawing and electron-donating groups, as well as diverse functionalities. At the same time, strong electron-acceptor substituents in the pyridine ring of the starting ureas reduce the product yield or even prevent the cyclocondensation step. The reaction can be easily scaled to gram quantities.

Discovery of pyrido[3,4-b]indol-1-one derivatives as novel non-covalent Bruton's tyrosine kinase (BTK) inhibitors

Bruton's tyrosine kinase (BTK) is an attractive target for the treatment of malignancy and inflammatory/autoimmune diseases. Most of the covalent BTK inhibitors would induce off-target side effects and drug resistance. To improve the drug safety of BTK inhibitors, non-covalent inhibitors have attracted more and more attention. We designed a series of novel pyrido[3,4-b]indol-1-one derivatives (N-A and N-B) via scaffold hopping from CGI-1746. The structure-activity relationship (SAR) of the newly-synthesized compounds was explored. The results showed that compounds 12 and 18 exhibited potent enzymatic potency against BTK with IC₅₀ values of 0.22 μM and 0.19 μM, respectively. In lymphoma cell lines U-937 cells and Ramos cells, compounds 12 and 18 displayed comparative antiproliferative activity with Ibrutinib. Moreover, compound 12 induced G1-phase cell cycle arrest and apoptosis in U-937 cells. And it could effectively inhibit tumor growth in U-937 xenograft mouse model (TGI = 41.90% at 50 mg/kg). In all, the new pyrido[3,4-b]indol-1-one derivatives have the antitumor potency by BTK inhibition and were worthy of further exploration.

Recent Advances in BTK Inhibitors for the Treatment of Inflammatory and Autoimmune Diseases

Bruton’s tyrosine kinase (BTK) plays a crucial role in B-cell receptor and Fc receptor signaling pathways. BTK is also involved in the regulation of Toll-like receptors and chemokine receptors. Given the central role of BTK in immunity, BTK inhibition represents a promising therapeutic approach for the treatment of inflammatory and autoimmune diseases. Great efforts have been made in developing BTK inhibitors for potential clinical applications in inflammatory and autoimmune diseases. This review covers the recent development of BTK inhibitors at preclinical and clinical stages in treating these diseases. Individual examples of three types of inhibitors, namely covalent irreversible inhibitors, covalent reversible inhibitors, and non-covalent reversible inhibitors, are discussed with a focus on their structure, bioactivity and selectivity. Contrary to expectations, reversible BTK inhibitors have not yielded a significant breakthrough so far. The development of covalent, irreversible BTK inhibitors has progressed more rapidly. Many candidates entered different stages of clinical trials; tolebrutinib and evobrutinib are undergoing phase 3 clinical evaluation. Rilzabrutinib, a covalent reversible BTK inhibitor, is now in phase 3 clinical trials and also offers a promising future. An analysis of the protein–inhibitor interactions based on published co-crystal structures provides useful clues for the rational design of safe and effective small-molecule BTK inhibitors.

Next-generation Bruton's tyrosine kinase inhibitor BIIB091 selectively and potently inhibits B cell and Fc receptor signaling and downstream functions in B cells and myeloid cells

Objectives

Bruton's tyrosine kinase (BTK) plays a non-redundant signaling role downstream of the B-cell receptor (BCR) in B cells and the receptors for the Fc region of immunoglobulins (FcR) in myeloid cells. Here, we characterise BIIB091, a novel, potent, selective and reversible small-molecule inhibitor of BTK.

Methods

BIIB091 was evaluated in vitro and in vivo in preclinical models and in phase 1 clinical trial.

Results

In vitro, BIIB091 potently inhibited BTK-dependent proximal signaling and distal functional responses in both B cells and myeloid cells with IC₅₀s ranging from 3 to 106 nm, including antigen presentation to T cells, a key mechanism of action thought to be underlying the efficacy of B cell-targeted therapeutics in multiple sclerosis. BIIB091 effectively sequestered tyrosine 551 in the kinase pocket by forming long-lived complexes with BTK with t _1/2 of more than 40 min, thereby preventing its phosphorylation by upstream kinases. As a key differentiating feature of BIIB091, this property explains the very potent whole blood IC₅₀s of 87 and 106 nm observed with stimulated B cells and myeloid cells, respectively. In vivo, BIIB091 blocked B-cell activation, antibody production and germinal center differentiation. In phase 1 healthy volunteer trial, BIIB091 inhibited naïve and unswitched memory B-cell activation, with an in vivo IC₅₀ of 55 nm and without significant impact on lymphoid or myeloid cell survival after 14 days of dosing.

Conclusion

Pharmacodynamic results obtained in preclinical and early clinical settings support the advancement of BIIB091 in phase 2 clinical trials.

Discovery of potent and selective reversible Bruton's tyrosine kinase inhibitors

Bruton's tyrosine kinase (BTK) is a cytoplasmic, non-receptor tyrosine kinase member of the TEC family of tyrosine kinases. Pre-clinical and clinical data have shown that targeting BTK can be used for the treatment for B-cell disorders. Here we disclose the discovery of a novel imidazo[4,5-b]pyridine series of potent, selective reversible BTK inhibitors through a rational design approach. From a starting hit molecule 1, medicinal chemistry optimization led to the development of a lead compound 30, which exhibited 58 nM BTK inhibitory potency in human whole blood and high kinome selectivity. Additionally, the compound demonstrated favorable pharmacokinetics (PK), and showed potent dose-dependent efficacy in a rat CIA model.

The Results of Well-conducted Negative Clinical Trials Should Be Reported in a Peer-reviewed Journal

We expect that the pathogenesis, manifestations, and successful management of disease will be fully reported in peer-reviewed journals. However, there are multiple publications addressing the likelihood that clinical trials that do not report a positive result are underreported in the medical literature, with a maximum of 50% of negative studies published, even after 5 years of availability of their results1,2.

Bleeding by Bruton Tyrosine Kinase-Inhibitors: Dependency on Drug Type and Disease

Bruton tyrosine kinase (Btk) is expressed in B-lymphocytes, myeloid cells and platelets, and Btk-inhibitors (BTKi) are used to treat patients with B-cell malignancies, developed against autoimmune diseases, have been proposed as novel antithrombotic drugs, and been tested in patients with severe COVID-19. However, mild bleeding is frequent in patients with B-cell malignancies treated with the irreversible BTKi ibrutinib and the recently approved 2nd generation BTKi acalabrutinib, zanubrutinib and tirabrutinib, and also in volunteers receiving in a phase-1 study the novel irreversible BTKi BI-705564. In contrast, no bleeding has been reported in clinical trials of other BTKi. These include the brain-penetrant irreversible tolebrutinib and evobrutinib (against multiple sclerosis), the irreversible branebrutinib, the reversible BMS-986142 and fenebrutinib (targeting rheumatoid arthritis and lupus erythematodes), and the reversible covalent rilzabrutinib (against pemphigus and immune thrombocytopenia). Remibrutinib, a novel highly selective covalent BTKi, is currently in clinical studies of autoimmune dermatological disorders. This review describes twelve BTKi approved or in clinical trials. By focusing on their pharmacological properties, targeted disease, bleeding side effects and actions on platelets it attempts to clarify the mechanisms underlying bleeding. Specific platelet function tests in blood might help to estimate the probability of bleeding of newly developed BTKi.

Antineoplastic kinase inhibitors: A new class of potent anti-amoebic compounds

Entamoeba histolytica is a protozoan parasite which infects approximately 50 million people worldwide, resulting in an estimated 70,000 deaths every year. Since the 1960s E. histolytica infection has been successfully treated with metronidazole. However, drawbacks to metronidazole therapy exist, including adverse effects, a long treatment course, and the need for an additional drug to prevent cyst-mediated transmission. E. histolytica possesses a kinome with approximately 300–400 members, some of which have been previously studied as potential targets for the development of amoebicidal drug candidates. However, while these efforts have uncovered novel potent inhibitors of E. histolytica kinases, none have resulted in approved drugs. In this study we took the alternative approach of testing a set of twelve previously FDA-approved antineoplastic kinase inhibitors against E. histolytica trophozoites in vitro. This resulted in the identification of dasatinib, bosutinib, and ibrutinib as amoebicidal agents at low-micromolar concentrations. Next, we utilized a recently developed computational tool to identify twelve additional drugs with human protein target profiles similar to the three initial hits. Testing of these additional twelve drugs led to the identification of ponatinib, neratinib, and olmutinib were identified as highly potent, with EC₅₀ values in the sub-micromolar range. All of these six drugs were found to kill E. histolytica trophozoites as rapidly as metronidazole. Furthermore, ibrutinib was found to kill the transmissible cyst stage of the model organism E. invadens. Ibrutinib thus possesses both amoebicidal and cysticidal properties, in contrast to all drugs used in the current therapeutic strategy. These findings together reveal antineoplastic kinase inhibitors as a highly promising class of potent drugs against this widespread and devastating disease.

Every year, nearly a hundred thousand people worldwide die from infection by the intestinal parasite Entamoeba histolytica, despite the widespread availability of metronidazole as a treatment. Here we report that six anticancer drugs of the kinase inhibitor class possess potent anti-amoebic properties, with one of them killing both actively dividing parasite and its transmissible cysts. These anticancer kinase inhibitors, including the dual-purpose drug with both amoebicidal and cysticidal activities may be used to treat amoebiasis, especially in cancer patients or in life-threatening brain- and liver-infecting forms of the disease.

Small-Molecule Kinase Inhibitors for the Treatment of Nononcologic Diseases

Great successes have been achieved in developing small-molecule kinase inhibitors as anticancer therapeutic agents. However, kinase deregulation plays essential roles not only in cancer but also in almost all major disease areas. Accumulating evidence has revealed that kinases are promising drug targets for different diseases, including cancer, autoimmune diseases, inflammatory diseases, cardiovascular diseases, central nervous system disorders, viral infections, and malaria. Indeed, the first small-molecule kinase inhibitor for treatment of a nononcologic disease was approved in 2011 by the U.S. FDA. To date, 10 such inhibitors have been approved, and more are in clinical trials for applications other than cancer. This Perspective discusses a number of kinases and their small-molecule inhibitors for the treatment of diseases in nononcologic therapeutic fields. The opportunities and challenges in developing such inhibitors are also highlighted.

Safety, pharmacokinetics and pharmacodynamics of BI 705564, a highly selective, covalent inhibitor of Bruton's tyrosine kinase, in Phase I clinical trials in healthy volunteers

Aims

To evaluate the safety, pharmacokinetics and pharmacodynamics of single‐ and multiple‐rising doses (MRDs) of BI 705564 and establish proof of mechanism.

Methods

BI 705564 was studied in 2 placebo‐controlled, Phase I clinical trials testing single‐rising doses (1–160 mg) and MRDs (1–80 mg) of BI 705564 over 14 days in healthy male volunteers. Blood samples were analysed for BI 705564 plasma concentration, Bruton's tyrosine kinase (BTK) target occupancy (TO) and CD69 expression in B cells stimulated ex vivo. A substudy was conducted in allergic, otherwise healthy, MRD participants. Safety was assessed in both studies.

Results

All doses of BI 705564 were well tolerated. Geometric mean BI 705564 plasma terminal half‐life ranged from 10.1 to 16.9 hours across tested doses, with no relevant accumulation after multiple dosing. Doses ≥20 mg resulted in ≥85% average TO that was maintained for ≥48 hours after single‐dose administration. Functional effects of BTK signalling were demonstrated by dose‐dependent inhibition of CD69 expression. In allergic participants, BI 705564 treatment showed a trend in wheal size reduction in a skin prick test and complete inhibition of basophil activation. Mild bleeding‐related adverse events were observed with BI 705564; bleeding time increased in 1/12 participants (8.3%) who received placebo vs 26/48 (54.2%) treated with BI 705564.

Conclusion

BI 705564 showed efficient target engagement through durable TO and inhibition of ex vivo B‐cell activation, and proof of mechanism through effects on allergic skin responses. Mild bleeding‐related adverse events were probably related to inhibition of platelet aggregation by BTK inhibition.

Driving Potency with Rotationally Stable Atropisomers: Discovery of Pyridopyrimidinedione-Carbazole Inhibitors of BTK

Bruton's tyrosine kinase (BTK) has been shown to play a key role in the pathogenesis of autoimmunity. Therefore, the inhibition of the kinase activity of BTK with a small molecule inhibitor could offer a breakthrough in the clinical treatment of many autoimmune diseases. This Letter describes the discovery of BMS-986143 through systematic structure-activity relationship (SAR) development. This compound benefits from defined chirality derived from two rotationally stable atropisomeric axes, providing a potent and selective single atropisomer with desirable efficacy and tolerability profiles.

Measuring atropisomers of BMS-986142 using 2DLC as an enabling technology

BMS-986142 has been developed as an innovative Bruton's tyrosine kinase inhibitor for treatment of several autoimmune diseases. The drug substance of BMS-986142 may contain three potential atropisomeric impurities due to its unique structural characteristics. Developing a single liquid chromatography (LC) method to separate all four highly structurally related atropisomers and other process impurities from each other turned out to be a daunting task. Two-dimensional LC (2DLC) was found to be an extremely powerful enabling technology for extracting purity information out of the complex sample impurity profile and facilitated process development before a final single dimension method was discovered. The off-the-shelf 2DLC instrument could be configured to allow injection of the targeted first dimension peak through either no-loss multiple heart-cutting fractions or as a large, single volume fraction with on-line dilution. Excellent precision (relative standard deviation of 0.3 %) and recovery (101.2 ± 0.2 %) was achieved for an atropisomer impurity at a 10 % monitoring level in the first configuration with sensitivity down to 0.2 % w/w. With the second instrument configuration, which eliminated the need for fraction recombination, similar figures of merit were maintained for the second dimension at the cost of losing the ability to collect and park multiple fractions.

Small Molecule NF-κB Pathway Inhibitors in Clinic

Nuclear factor kappa B (NF-κB) signaling is implicated in all major human chronic diseases, with its role in transcription of hundreds of gene well established in the literature. This has propelled research into targeting the NF-κB pathways for modulating expression of those genes and the diseases mediated by them. In-spite of the critical, but often promiscuous role played by this pathway and the inhibition causing adverse drug reaction, currently many biologics, macromolecules, and small molecules that modulate this pathway are in the market or in clinical trials. Furthermore, many marketed drugs that were later found to also have NF-κB targeting activity were repurposed for new therapeutic interventions. Despite the rising importance of biologics in drug discovery, small molecules got around 76% of US-FDA (Food and Drug Administration-US) approval in the last decade. This encouraged us to review information regarding clinically relevant small molecule inhibitors of the NF-κB pathway from cell surface receptor stimulation to nuclear signaling. We have also highlighted the underexplored targets in this pathway that have potential to succeed in clinic.

Advances in the study of drug metabolism - symposium report of the 12th Meeting of the International Society for the Study of Xenobiotics (ISSX)

The 12th International Society for the Study of Xenobiotics (ISSX) meeting, held in Portland, OR, USA from July 28 to 31, 2019, was attended by diverse members of the pharmaceutical sciences community. The ISSX New Investigators Group provides learning and professional growth opportunities for student and early career members of ISSX. To share meeting content with those who were unable to attend, the ISSX New Investigators herein elected to highlight the "Advances in the Study of Drug Metabolism" symposium, as it engaged attendees with diverse backgrounds. This session covered a wide range of current topics in drug metabolism research including predicting sites and routes of metabolism, metabolite identification, ligand docking, and medicinal and natural products chemistry, and highlighted approaches complemented by computational modeling. In silico tools have been increasingly applied in both academic and industrial settings, alongside traditional and evolving in vitro techniques, to strengthen and streamline pharmaceutical research. Approaches such as quantum mechanics simulations facilitate understanding of reaction energetics toward prediction of routes and sites of drug metabolism. Furthermore, in tandem with crystallographic and orthogonal wet lab techniques for structural validation of drug metabolizing enzymes, in silico models can aid understanding of substrate recognition by particular enzymes, identify metabolic soft spots and predict toxic metabolites for improved molecular design. Of note, integration of chemical synthesis and biosynthesis using natural products remains an important approach for identifying new chemical scaffolds in drug discovery. These subjects, compiled by the symposium organizers, presenters, and the ISSX New Investigators Group, are discussed in this review.

Promises and pitfalls of targeted agents in chronic lymphocytic leukemia

Targeted agents have significantly improved outcomes for patients with chronic lymphocytic leukemia, particularly high-risk subgroups for whom chemoimmunotherapy previously offered limited efficacy. Two classes of agent in particular, the Bruton tyrosine kinase inhibitors (e.g., ibrutinib) and the B-cell lymphoma 2 inhibitor, venetoclax, induce high response rates and durable remissions in the relapsed/refractory and frontline settings. However, maturing clinical data have revealed promises and pitfalls for both agents. These drugs induce remissions and disease control in the majority of patients, often in situations where modest efficacy would be expected with traditional chemoimmunotherapy approaches. Unfortunately, in the relapsed and refractory setting, both agents appear to be associated with an inevitable risk of disease relapse and progression. Emerging patterns of resistance are being described for both agents but a common theme appears to be multiple sub-clonal drivers of disease progression. Understanding these mechanisms and developing effective and safe methods to circumvent the emergence of resistance will determine the longer-term utility of these agents to improve patients' quality and length of life. Rational drug combinations, optimised scheduling and sequencing of therapy will likely hold the key to achieving these important goals.

Ibrutinib Resistance Mechanisms and Treatment Strategies for B-Cell lymphomas

Chronic activation of B-cell receptor (BCR) signaling via Bruton tyrosine kinase (BTK) is largely considered to be one of the primary mechanisms driving disease progression in B-Cell lymphomas. Although the BTK-targeting agent ibrutinib has shown promising clinical responses, the presence of primary or acquired resistance is common and often leads to dismal clinical outcomes. Resistance to ibrutinib therapy can be mediated through genetic mutations, up-regulation of alternative survival pathways, or other unknown factors that are not targeted by ibrutinib therapy. Understanding the key determinants, including tumor heterogeneity and rewiring of the molecular networks during disease progression and therapy, will assist exploration of alternative therapeutic strategies. Towards the goal of overcoming ibrutinib resistance, multiple alternative therapeutic agents, including second- and third-generation BTK inhibitors and immunomodulatory drugs, have been discovered and tested in both pre-clinical and clinical settings. Although these agents have shown high response rates alone or in combination with ibrutinib in ibrutinib-treated relapsed/refractory(R/R) lymphoma patients, overall clinical outcomes have not been satisfactory due to drug-associated toxicities and incomplete remission. In this review, we discuss the mechanisms of ibrutinib resistance development in B-cell lymphoma including complexities associated with genomic alterations, non-genetic acquired resistance, cancer stem cells, and the tumor microenvironment. Furthermore, we focus our discussion on more comprehensive views of recent developments in therapeutic strategies to overcome ibrutinib resistance, including novel BTK inhibitors, clinical therapeutic agents, proteolysis-targeting chimeras and immunotherapy regimens.

Pharmacokinetics, pharmacodynamics, safety, tolerability, and mass balance of single and continuous intravenous infusion of SPT-07A in healthy volunteers

PURPOSE

SPT-07A is an intravenous injection of (+)-2-borneol being developed for the treatment of acute ischemic stroke. This study aimed to investigate the pharmacokinetics, pharmacodynamics, safety, tolerability, and mass balance of SPT-07A after sequentially administered single and multiple infusions of SPT-07A at 10 mg, 20 mg, or 40 mg.

METHODS

This phase I, double-blind, randomized, placebo-controlled, dose-escalation study was conducted in 36 Chinese healthy volunteers. Each cohort enrolled 12 eligible subjects, who were 9:3 randomized to receive SPT-07A or matching placebo during the two study occasions, that is, an initial single-dose occasion followed by a 7-day multiple-dose occasion with a dosing interval of 12 h. Pharmacokinetic, pharmacodynamic assessments regarding effects on the central nervous system (CNS) were performed pre-dose and several times post-dose. Safety and tolerability were evaluated throughout the study for each cohort.

RESULTS

Following single intravenous (i.v.) administration of 10 mg to 40 mg SPT-07A, the plasma SPT-07A concentration reached its peak by the end of infusion. Thereafter, the plasma concentration declined in a multiphase exponential manner with an average terminal elimination half-life of 3.85 to 8.93 h. The exposure parameters of SPT-07A increased dose proportionally. Steady state of SPT-07A was reached after 12-hourly i.v. administrations for 4 days with minimal accumulations. No significant difference of change-from-baseline was observed in the pharmacodynamic measurements between each of the three SPT-07A-treated groups and the placebo group. A total of 41 adverse events (AEs) were reported in 77.8% subjects at 10 mg (7/9), 20 mg (7/9), and 40 mg (7/9), respectively. The AE incidence in placebo group was also 77.8% (7/9). All AEs were mild or moderate in severity and self-limited. SPT-07A was mainly excreted in human urine in glucuronic acid conjugate forms. The total urine recovery rate approximated 84.69% of the administered dose.

CONCLUSIONS

SPT-07A was safe and well tolerated after single and multiple intravenous administrations of SPT-07A in the range of 10 mg to 40 mg. SPT-07A presented linear pharmacokinetics in human. Based on plasma exposure, the doses of 10-40 mg twice daily resulted in exposure levels comparable with those obtained at doses demonstrating potential efficacy on AIS animal models and were thus recommended as therapeutic exploratory doses in the phase II clinical trial.

B cell checkpoints in autoimmune rheumatic diseases

B cells have important functions in the pathogenesis of autoimmune diseases, including autoimmune rheumatic diseases. In addition to producing autoantibodies, B cells contribute to autoimmunity by serving as professional antigen-presenting cells (APCs), producing cytokines, and through additional mechanisms. B cell activation and effector functions are regulated by immune checkpoints, including both activating and inhibitory checkpoint receptors that contribute to the regulation of B cell tolerance, activation, antigen presentation, T cell help, class switching, antibody production and cytokine production. The various activating checkpoint receptors include B cell activating receptors that engage with cognate receptors on T cells or other cells, as well as Toll-like receptors that can provide dual stimulation to B cells via co-engagement with the B cell receptor. Furthermore, various inhibitory checkpoint receptors, including B cell inhibitory receptors, have important functions in regulating B cell development, activation and effector functions. Therapeutically targeting B cell checkpoints represents a promising strategy for the treatment of a variety of autoimmune rheumatic diseases.

Tyrosine kinase inhibitors for the treatment of rheumatoid arthritis: phase I to Ⅱ clinical trials

Introduction: Rheumatoid arthritis (RA) is a chronic, refractory disorder caused by autoimmunity in the synovial joints. Disease-modifying anti-rheumatic drugs (DMARDs) and biologicals offer remission in only two-thirds of RA patients within 3 months, hence new therapeutic approaches are necessary. Tyrosine kinase inhibitors (TKIs) are newly developed small molecule drugs which have demonstrated encouraging results in this disease.Areas covered: The key findings from phase I and II clinical trials that have investigated the use of novel TKIs in the treatment of RA are discussed. We examined the literature published between January 2014 to January 2019 using electronic databases including PubMed, Web of Science, Medline, Embase, and Google Scholar. Additional information about phase I and II trials on the ClinicalTrial.gov website up to January 2019 was also retrieved.Expert opinion: JAK inhibitors are promising drugs with sound efficacy and acceptable safety and may be beneficial to patients who do not respond to DMARDs and biologicals. The response rates among RA patients to TKIs are diverse; genetic and environmental factors may be involved in the varying responses which are closely related to the pathogenesis of RA. Future studies may reveal the underlying mechanisms of resistance and non-response.

Absence of Pharmacokinetic Interactions between the Bruton's Tyrosine Kinase Inhibitor Fenebrutinib and Methotrexate

Fenebrutinib (GDC-0853) is an orally administered small molecule inhibitor of Bruton's tyrosine kinase being investigated for treatment of rheumatoid arthritis in patients with inadequate responses to methotrexate (MTX). This study interrogated the potential for pharmacokinetic drug interactions between fenebrutinib and MTX. Eighteen healthy male subjects were enrolled in the study. They received a single oral dose of MTX (7.5 mg) on day 1 followed by a 13-day washout period. Subsequently, on days 15-20 the participants received 200 mg of fenebrutinib twice daily. On day 21, they received a 7.5 mg dose of MTX and a 200 mg dose of fenebrutinib under fasting conditions. The geometric mean ratios of MTX area under the plasma concentration-time curve (AUC) and C _max on day 21 relative to day 1 (90% confidence interval [CI]) were 0.96 (0.88-1.04) and 1.05 (0.94-1.18), respectively. The geometric mean ratios of fenebrutinib AUC and C _max for day 21 relative to day 20 (90% CI) were 1.03 (0.95-1.11) and 1.02 (0.90-1.15), respectively. The combination treatment was well tolerated, with an adverse event profile similar to that reported in other MTX trials. These results indicate that there is no clinically significant pharmacokinetic interaction between fenebrutinib and MTX.

Molecular Modeling Studies on Carbazole Carboxamide Based BTK Inhibitors Using Docking and Structure-Based 3D-QSAR

Rheumatoid arthritis (RA) is the second common rheumatic immune disease with chronic, invasive inflammatory characteristics. Non-steroidal anti-inflammatory drugs (NSAIDs), slow-acting anti-rheumatic drugs (SAARDs), or glucocorticoid drugs can improve RA patients’ symptoms, but fail to cure. Broton’s tyrosine kinase (BTK) inhibitors have been proven to be an efficacious target against autoimmune indications and B-cell malignancies. Among the current 11 clinical drugs, only BMS-986142, classified as a carbazole derivative, is used for treating RA. To design novel and highly potent carbazole inhibitors, molecular docking and three dimensional quantitative structure–activity relationship (3D-QSAR) were applied to explore a dataset of 132 new carbazole carboxamide derivatives. The established comparative molecular field analysis (CoMFA) (q² = 0.761, r² = 0.933) and comparative molecular similarity indices analysis (CoMSIA) (q² = 0.891, r² = 0.988) models obtained high predictive and satisfactory values. CoMFA/CoMSIA contour maps demonstrated that bulky substitutions and hydrogen-bond donors were preferred at R₁ and 1-position, respectively, and introducing hydrophilic substitutions at R₁ and R₄ was important for improving BTK inhibitory activities. These results will contribute to the design of novel and highly potent BTK inhibitors.

Discovery of GDC-0853: A Potent, Selective, and Noncovalent Bruton's Tyrosine Kinase Inhibitor in Early Clinical Development

Bruton's tyrosine kinase (Btk) is a nonreceptor cytoplasmic tyrosine kinase involved in B-cell and myeloid cell activation, downstream of B-cell and Fcγ receptors, respectively. Preclinical studies have indicated that inhibition of Btk activity might offer a potential therapy in autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. Here we disclose the discovery and preclinical characterization of a potent, selective, and noncovalent Btk inhibitor currently in clinical development. GDC-0853 (29) suppresses B cell- and myeloid cell-mediated components of disease and demonstrates dose-dependent activity in an in vivo rat model of inflammatory arthritis. It demonstrates highly favorable safety, pharmacokinetic (PK), and pharmacodynamic (PD) profiles in preclinical and Phase 2 studies ongoing in patients with rheumatoid arthritis, lupus, and chronic spontaneous urticaria. On the basis of its potency, selectivity, long target residence time, and noncovalent mode of inhibition, 29 has the potential to be a best-in-class Btk inhibitor for a wide range of immunological indications.

Are BTK and PLCG2 mutations necessary and sufficient for ibrutinib resistance in chronic lymphocytic leukemia?

INTRODUCTION

Ibrutinib is the first BTK inhibitor to show efficacy in chronic lymphocytic leukemia (CLL) and is also the first BTK inhibitor to which patients have developed resistance. Mutations in BTK and PLCG2 are found in ≈80% of CLL patients with acquired resistance to ibrutinib, but it remains unclear if these mutations are merely associated with disease relapse or directly cause it. Areas covered: Unique properties of both CLL and ibrutinib that complicate attempts to definitively conclude whether BTK/PLCG2 mutations are passengers or drivers of ibrutinib-resistant disease are reviewed. Characteristics of mutations that drive drug resistance are summarized and whether BTK/PLCG2 mutations possess these is discussed. These characteristics include (1) identification in multiple patients with acquired resistance, (2) in vitro validation of drug-resistant properties, (3) mutual exclusivity with one another, (4) increasing frequency over time on drug, and (5) high frequency at the time and site of clinical relapse. Expert commentary: While BTK/PLCG2 mutations have characteristics suggesting that they can drive ibrutinib resistance, this conclusion remains formally unproven until specific inhibition of such mutations is shown to cause regression of ibrutinib-resistant CLL. Data suggest that alternative mechanisms of resistance do exist in some patients.