Synthesis and characterization of novel combretastatin analogues of 1,1-diaryl vinyl sulfones, with antiproliferative potential via in-silico and in-vitro studies.

Novel 1,1-diaryl vinyl-sulfones analogues of combretastatin CA-4 were synthesized via Suzuki-Miyaura coupling method and screened for in-vitro antiproliferative activity against four human cancer cell lines: MDA-MB 231(breast cancer), HeLa (cervical cancer), A549 (lung cancer), and IMR-32 (neuroblast cancer), along with a normal cell line HEK-293 (human embryonic kidney cell) by employing 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. The compounds synthesised had better cytotoxicity against the A549 and IMR-32 cell lines compared to HeLa and MDA-MB-231 cell lines. The synthesized compounds also showed significant activity on MDA-MB-231 cancer cell line with IC50 of 9.85-23.94 µM, and on HeLa cancer cell line with IC50 of 8.39-11.70 µM relative to doxorubicin having IC50 values 0.89 and 1.68 µM respectively for MDA-MB-231 and HeLa cell lines. All the synthesized compounds were not toxic to the growth of normal cells, HEK-293. They appear to have a higher binding affinity for the target protein, tubulin, PDB ID = 5LYJ (beta chain), relative to the reference compounds, CA4 (- 7.1 kcal/mol) and doxorubicin (- 7.2 kcal/mol) except for 4E, 4M, 4N and 4O. The high binding affinity for beta-tubulin did not translate into enhanced cytotoxicity but the compounds (4G, 4I, 4J, 4M, 4N, and 4R, all having halogen substituents) that have a higher cell permeability (as predicted in-silico) demonstrated an optimum cytotoxicity against the tested cell lines in an almost uniform manner for all tested cell lines. The in-silico study provided insight into the role that cell permeability plays in enhancing the cytotoxicity of this class of compounds and as potential antiproliferative agents.

Absorption and Distribution of Toltrazuril and Toltrazuril Sulfone in Plasma, Intestinal Tissues and Content of Piglets after Oral or Intramuscular Administration.

Piglet coccidiosis due to Cystoisospora suis is a major cause of diarrhea and poor growth worldwide. It can effectively be controlled by application of toltrazuril (TZ), and oral formulations have been licensed for many years. Recently, the first parenteral formulation containing TZ in combination with iron (gleptoferron) was registered in the EU for the prevention of coccidiosis and iron deficiency anemia, conditions in suckling piglets requiring routine preventive measures. This study evaluated the absorption and distribution of TZ and its main metabolite, toltrazuril sulfone (TZ-SO2), in blood and intestinal tissues after single oral (20 mg/kg) or single intramuscular (45 mg/piglet) application of TZ. Fifty-six piglets were randomly allocated to the two treatment groups. Animals were sacrificed 1-, 5-, 13-, and 24-days post-treatment and TZ and TZ-SO2 levels were determined in blood, jejunal tissue, ileal tissue, and mixed jejunal and ileal content (IC) by high performance liquid chromatography (HPLC). Intramuscular application resulted in significantly higher and more sustained concentrations of both compounds in plasma, intestinal tissue, and IC. Higher concentrations after oral dosing were only observed one day after application of TZ in jejunum and IC. Toltrazuril was quickly metabolized to TZ-SO2 with maximum concentrations on day 13 for both applications. Remarkably, TZ and TZ-SO2 accumulated in the jejunum, the primary predilection site of C. suis, independently of the administration route, which is key to their antiparasitic effect.

A phase I study of the anaplastic lymphoma kinase inhibitor ceritinib in combination with gemcitabine-based chemotherapy in patients with advanced solid tumors.

In this phase I, dose-escalation study, we sought to determine the maximum tolerated dose (MTD) of the anaplastic lymphoma kinase/c-ROS oncogene 1 receptor (ALK/ROS1) inhibitor ceritinib in combination with gemcitabine-based chemotherapy in patients with advanced solid tumors. Secondary objectives were characterization of the safety profile, pharmacokinetics and preliminary efficacy of these combinations, and identification of potential biomarkers of efficacy. Ceritinib was combined with gemcitabine (Arm 1), gemcitabine/nab-paclitaxel (Arm 2) or gemcitabine/cisplatin (Arm 3). Drug concentrations in plasma were measured by tandem mass spectrometric detection (LC-MS/MS). We analyzed archival tumor tissue for ALK, ROS1, hepatocyte growth factor receptor (c-MET) and c-Jun N-terminal kinase (JNK) expression by immunohistochemistry. Arm 2 closed early secondary to toxicity. Twenty-one patients were evaluable for dose-limiting toxicity (DLT). There was one DLT in Arm 1 (grade 3 ALT increase) and three DLTs in Arm 3 (grade 3 acute renal failure, grade 3 thrombocytopenia, grade 3 dyspnea). The MTD of ceritinib was determined to be 600 mg (Arm 1) and 450 mg orally daily (Arm 3). Main toxicities were hematologic, constitutional and gastrointestinal as expected by the chemotherapy backbone. The apparent clearance for ceritinib decreased substantially after repeated dosing; cisplatin did not significantly affect the pharmacokinetics of ceritinib. The overall response rate was 20%; the median progression-free survival was 4.8 months. Three out of five response-evaluable cholangiocarcinoma patients had clinical benefit. Increased expression of c-MET was associated with a lack of clinical benefit. Ceritinib in combination with gemcitabine and gemcitabine/cisplatin has a manageable toxicity profile. Further development of this strategy in tumors with ALK or ROS1 fusions is warranted.

Effect of ceritinib on the pharmacokinetics of coadministered CYP3A and 2C9 substrates: a phase I, multicenter, drug-drug interaction study in patients with ALK + advanced tumors.

PURPOSE: Ceritinib is an ALK receptor tyrosine kinase inhibitor approved as first- and second-line treatment in adult patients with ALK + metastatic non-small cell lung cancer (NSCLC). The study investigated the drug-drug interaction (DDI) potential of ceritinib when coadministered with midazolam and warfarin as probe substrates for CYP3A and CYP2C9 activity, respectively. METHODS: This was a phase I, multicenter, open-label, single sequence, crossover DDI study in 33 adult patients with ALK + NSCLC or other advanced tumors. A single dose of a cocktail consisting of midazolam and warfarin was administered with and without concomitant administration of ceritinib. The primary objective was to evaluate the pharmacokinetics of midazolam and warfarin. Secondary objectives included pharmacokinetics, safety, tolerability, overall response rate (ORR), and duration of response (DOR) of ceritinib 750 mg once daily. RESULTS: Ceritinib inhibited CYP3A-mediated metabolism of midazolam, resulting in a markedly increased AUC (geometric mean ratio [90% confidence interval]) by 5.4-fold (4.6, 6.3). Ceritinib also led to an increase in the AUC of S-warfarin by 54% (36%, 75%). The pharmacokinetics and safety profile of ceritinib in this study are consistent with previous reports and no new safety signals were reported. Among the 19 patients with NSCLC, efficacy (ORR: 42.1% and DCR: 63.2%) was similar to that reported previously in studies of pretreated patients with ALK + NSCLC. CONCLUSION: Ceritinib is a strong CYP3A inhibitor and a weak CYP2C9 inhibitor. These findings should be reflected as actionable clinical recommendations in the prescribing information for ceritinib with regards to concomitant medications whose pharmacokinetics may be altered by ceritinib.

Safety and Antitumor Activity of Repeated ASP3026 Administration in Japanese Patients with Solid Tumors: A Phase I Study.

BACKGROUND AND OBJECTIVE: Anaplastic lymphoma kinase gene rearrangements (ALKr) resulting in EML4-ALK proteins occur in a subset of solid tumors and are targeted by ALK inhibitors. Given the development of drug resistance to ALK inhibitors, ALK inhibitors with different kinase selectivity are required. METHODS: This phase I, non-randomized, open-label study evaluated the dose-limiting toxicity (DLT), safety, pharmacokinetics, and antitumor activity of ASP3026, a second-generation ALK inhibitor, in Japanese patients with solid tumors. Between 1 June 2011 and 20 January 2014, 29 patients received different daily doses of ASP3026 in the escalation (25 mg, n = 3; 50 mg, n = 3; 75 mg, n = 3; 125 mg, n = 4; 200 mg, n = 3; or 325 mg, n = 7) and expansion (200 mg, n = 6) cohorts. RESULTS: Three patients had DLTs at the 325-mg dose: cataract exacerbation, increased aspartate transaminase and alanine transaminase, and impaired hepatic function (all Grade 3 severity). Thus, the maximum tolerated dose was 200 mg. The treatment-emergent adverse event incidence was 100%; the most common events were nausea (n = 8, 27.6%), decreased appetite (n = 10, 34.5%), and fatigue (n = 9, 31.0%) of mild or moderate severity. Six patients were positive for ALK protein and three had ALKr. Two patients achieved partial responses: one with Ewing sarcoma (75-mg dose group) and one with an ALKr-positive inflammatory myofibroblastic tumor (125-mg dose group). CONCLUSION: ASP3026 at a 200-mg dose may provide therapeutic benefit for patients with solid tumors, with a tolerable safety profile. CLINICAL TRIAL REGISTRATION: This study is registered at ClinicalTrials.gov under the identifier NCT01401504 on July 25, 2011.

A preliminary assessment of oral monepantel's tolerability and pharmacokinetics in individuals with treatment-refractory solid tumors.

PURPOSE: Monepantel is an approved veterinary anthelmintic with a strong safety profile. Preclinical evidence suggests novel mTOR pathway-associated anticancer activity. An open-label Phase I trial assessed tolerability, pharmacokinetics, pharmacodynamics and PET-CT imaging following oral Zolvix® monepantel administration to adults with treatment refractory, progressing and unresectable solid tumors. METHODS: Subjects were scheduled to daily home-based monepantel administration for 28 days in a 3 + 3 dose escalation study (5.0, 25.0 and 62.5 mg/kg bw). RESULTS: Of 41 reported drug-related AEs, 68% were Grade 1 and 24% were Grade 2; 35 AEs related to gastrointestinal effects including very poor palatability. DLT and MTD could not be determined due to early termination. Myelosuppression was not observed at the lowest level tested. Three of four Cohort 1 subjects had reduced mTOR pathway marker p-RPS6KB1 levels in PBMCs and achieved RECISTv1.1 SD by CT; one had progressive bony metastases by FDG-PET. One subject recorded PD on day 28, correlating with no detectable plasma monepantel from day 7. Monepantel sulfone dominated monepantel in pharmacokinetics. Both Cohort 2 subjects withdrew early due to AEs and the trial was terminated. CONCLUSIONS: Short-term 5 mg/kg bw monepantel administration provides a combined steady-state trough plasma monepantel and monepantel sulfone concentration of 0.5 µM. Gastrointestinal AEs including very poor palatability are concerning and suggested to be resolved by future drug product reformulation. RECISTv1.1, p-RPS6KB1 and plasma tumor marker outcomes provide preliminary evidence of anticancer activity.

Drug-Drug Interaction Risk Assessment of Esaxerenone as a Perpetrator by In Vitro Studies and Static and Physiologically Based Pharmacokinetic Models.

Esaxerenone (CS-3150) is a novel, oral, nonsteroidal, selective mineralocorticoid receptor blocker approved for the treatment of hypertension in Japan. Here, the drug-drug interaction (DDI) potential of esaxerenone was evaluated in vitro, and its impact in clinical practice was estimated. Esaxerenone exhibited time-dependent inhibition and induction of CYP3A. When the clinical impacts of esaxerenone on the inhibition and induction of CYP3A were estimated separately by using a mechanistic static model, the predicted area under the curve ratios (AUCRs) of midazolam, a typical CYP3A substrate, were 1.80 and 0.31, respectively, suggesting that the DDI potential of esaxerenone cannot be neglected. Because it was suggested that DDIs mainly occur in the intestine, predictions using concentration-time profiles in each segment of the gastrointestinal tract were performed with GastroPlus, a physiologically based pharmacokinetic (PBPK) modeling software. The predicted AUCR of midazolam was approximately 1.2, which is close to that in a clinical study, despite the difficulty of predicting DDIs for compounds with both inhibition and induction effects. When only inhibition or induction was incorporated into a model, the AUCR of midazolam changed depending on the dosing period and dose level of esaxerenone and the timing of midazolam administration. However, the AUCR calculated by incorporating both effects remained almost constant. This study shows the ability of PBPK models to simulate weak DDIs via intestinal CYP3A and that esaxerenone has low DDI potential as a perpetrator because of the offset of inhibition and induction. SIGNIFICANCE STATEMENT: Weak CYP3A inhibition and/or induction sometimes cause DDIs in the intestine but not the liver. Because strong inhibitors maximally inhibit intestinal CYP3A, the predictability of weak DDIs in the intestine should be evaluated further. Here, we simulate the DDIs of esaxerenone as a perpetrator by using physiologically based pharmacokinetic modeling focusing on the intestine and offset of inhibition and induction.

A selective and robust UPLC-MS/MS method for the simultaneous quantitative determination of anlotinib, ceritinib and ibrutinib in rat plasma and its application to a pharmacokinetic study.

A selective and robust UPLC-MS/MS method has been firstly developed for simultaneous determination of three anti-tumor tyrosine kinase inhibitors (anlotinib, ANL; ceritinib, CER; ibrutinib, IBR) in rat plasma using cost-effective protein precipitation extraction. LC separation was achieved on Waters XBrige C18 column (50 mm × 2.1 mm, 3.5 µm) under gradient conditions in a run time of 5 min. ESI+ was involved through mass spectrometry. Multiple reaction monitoring transitions were at m/z 408.2 → 339.2 for ANL, 558.2 → 433.2 for CER, 441.0 → 138.0 for IBR, 285.0 → 193.1 for diazepam (internal standard), respectively. The optimized method was validated based on US FDA guideline, EMEA guideline as well as Pharmacopoeia of the People's Republic of China. The assay was linear in the range of 0.1-20 ng mL-1 for ANL, 2-1000 ng mL-1 for CER, 1-500 ng mL-1 for IBR. Intra- and inter-day accuracy and precision for all analytes were ≦13.84% and ≦12.56%, respectively. ANL, CER and IBR were sufficiently stable under most investigated conditions. The optimized method was successfully applied for a pharmacokinetic study after single oral gavage administration of mixture (ANL, CER and IBR) at dose of 6 mg kg-1, 25 mg kg-1 and 10 mg kg-1.

Oncoprotein Inhibitor Rigosertib Loaded in ApoE-Targeted Smart Polymersomes Reveals High Safety and Potency against Human Glioblastoma in Mice.

The unbiased cytotoxicity and blood-brain barrier (BBB) impermeability render common chemotherapeutics nonviable for treating glioblastoma (GBM) patients. Although rigosertib (RGS), a RAS effector protein inhibitor, has shown low toxicity to healthy cells and high efficacy toward various cancer cells by inactivating PI3K-Akt, it hardly overcomes the BBB barricade. Here, we report that RGS loaded in apolipoprotein E derived peptide (ApoE)-targeted chimaeric polymersomes (ApoE-CP) is safe and highly potent against human GBM in vivo. ApoE-CP exhibited stable loading of RGS in its lumen, giving RGS nanoformulations (ApoE-CP-RGS) with a size of 60 nm and reduction-triggered drug release behavior. Notably, ApoE-CP-RGS induction markedly enhanced the G2/M cell cycle arrest and inhibitory effect in U-87 MG glioblastoma cells compared with the nontargeted CP-RGS and free RGS. The therapeutic outcomes in orthotopic U-87 MG GBM models demonstrated that ApoE-CP-RGS brought about effective GBM inhibition, greatly prolonged survival time, and depleted adverse effects. Rigosertib formulated in ApoE-targeted chimaeric polymersomes has emerged as a novel, highly specific, efficacious, and nontoxic treatment for glioblastoma.

Safety and efficacy of the human neutrophil elastase inhibitor BAY 85-8501 for the treatment of non-cystic fibrosis bronchiectasis: A randomized controlled trial.

BACKGROUND: There are only limited treatment options for patients with non-cystic fibrosis bronchiectasis (non-CF BE). Human neutrophil elastase (HNE) is a mediator of tissue destruction in non-CF BE. BAY 85-8501, a selective and reversible HNE inhibitor, could represent a new treatment option for this disease. METHODS: This was a phase 2a, randomized, placebo-controlled, double-blind, parallel-group study. The primary objective was to assess the safety and tolerability of 1 mg BAY 85-8501 once daily (OD) for 28 days compared with placebo in patients with non-CF BE. Secondary objectives were to investigate the effects of 4 weeks of treatment with BAY 85-8501 on health-related quality of life, pulmonary function, and inflammatory and tissue damage biomarkers in sputum, blood and/or urine, and to evaluate the pharmacokinetics of BAY 85-8501. RESULTS: Overall, 94 patients (mean age, 66 years; 53% male) were randomized (n = 47 per group), and 82 completed the study (BAY 85-8501, n = 37; placebo, n = 45). Treatment-emergent adverse events (TEAEs) occurred in 31 patients (66%) taking BAY 85-8501 and in 36 patients (77%) taking placebo, and were mostly mild or moderate. The serious TEAEs (BAY 85-8501, n = 3; placebo, n = 1) were not considered to be study-drug related. There were no changes in pulmonary function parameters from baseline to end of treatment, and health-related quality of life did not improve in any group. HNE activity in blood after zymosan challenge decreased significantly with BAY 85-8501 treatment (P = 0.0250 versus placebo). There were no significant differences in other biomarkers between treatment groups, with the exception of a small increase in interleukin-8 levels in sputum in the BAY 85-8501 group. Trough plasma concentrations of BAY 85-8501 plateaued after 2 weeks. CONCLUSIONS: 1 mg BAY 85-8501 OD had a favourable safety and tolerability profile when administered for 28 days to patients with non-CF BE. Further studies with a longer treatment duration are needed to evaluate the potential clinical efficacy in this study population.

Characterization of in vitro metabolism of focal adhesion kinase inhibitors by LC/MS/MS.

Focal adhesion kinase (FAK), a non-receptor tyrosine kinase, is critically involved in cell migration, spreading and proliferation at the early step of various cancers. Small molecule inhibitors of FAK are effective to inhibit its activation in the process of tumor formation in cell. To better understand biotransformation of FAK inhibitors, this work has investigated in vitro phase I metabolism of inhibitors (namely PF-573228, PF-562271 and PF-03814735) by rat liver microsomes model. Using liquid chromatography - quadrupole time of flight mass spectrometry and tandem mass spectrometry (LC/Q-TOF/MS and MS/MS), three metabolites of PF-573228 and PF-562271 were observed and characterized, respectively. These in vitro metabolites were reported for the first time. The structures and fragmentation patterns of these metabolites were elucidated, and phase I metabolic pathways for FAK inhibitors were proposed. The main metabolic pathways of PF-573228 were hydroxylation, dehydrogenation and N-dealkylation. For PF-562271, they were hydroxylation and dehydrogenation. Hydroxylation was observed as the primary metabolism for PF-0381473.

Synthesis, molecular properties prediction and biological evaluation of indole-vinyl sulfone derivatives as novel tubulin polymerization inhibitors targeting the colchicine binding site.

Twenty-two novel indole-vinyl sulfone derivatives were designed, synthesized and evaluated as tubulin polymerization inhibitors. The physicochemical and drug-likeness properties of all target compounds were predicted by Osiris calculations. All compounds were evaluated for their antiproliferative activities, among them, compound 7f exhibited the most potent activity against a panel of cancer cell lines, which was 2-7 folds more potent than our previously reported compound 4. Especially, 7f displayed about 8-fold improvement of selective index as compared with compound 4, indicating that 7f might have lower toxicity. Besides, 7f inhibited the microtubule polymerization by binding to the colchicine site of tubulin. Further investigations showed that compound 7f effectively disrupted microtubule network, caused cell cycle arrest at G2/M phase and induced cell apoptosis in K562 cells. Moreover, 7f reduced the cell migration and disrupted capillary-like tube formation in HUVEC cells. Importantly, the in vivo anti-tumor activity of 7f was validated in H22 liver cancer xenograft mouse model without apparent toxicity, suggesting that 7f is a promising anti-tubulin agent for cancer therapy.

Pharmacokinetic-Pharmacodynamic Assessment of the Hepatic and Bone Marrow Toxicities of the New Trypanoside Fexinidazole.

Fexinidazole is a novel oral treatment for human African trypanosomiasis caused by Trypanosoma brucei gambiense (g-HAT). Fexinidazole also has activity against T. cruzi, the causative agent of Chagas disease. During the course of a dose ranging assessment in patients with chronic indeterminate Chagas disease, delayed neutropenia and significant increases in hepatic transaminases were observed and clinical investigations were suspended. We retrospectively analyzed all available pharmacokinetic and pharmacodynamic data on fexinidazole in normal healthy volunteers and in patients with Chagas disease and g-HAT to assess the determinants of toxicity. A population pharmacokinetic model was fitted to plasma concentrations (n = 4,549) of the bioactive fexinidazole sulfone metabolite, accounting for the majority of the bioactive exposure, from three phase 1 studies, two g-HAT phase 2/3 field trials, and one Chagas disease phase 2 field trial (n = 462 individuals in total). Bayesian exposure-response models were then fitted to hematological and liver-related pharmacodynamic outcomes in Chagas disease patients. Neutropenia, reductions in platelet counts, and elevations in liver transaminases were all found to be exposure dependent and, thus, dose dependent in patients with Chagas disease. Clinically insignificant transient reductions in neutrophil and platelet counts consistent with these exposure-response relationships were observed in patients with g-HAT. In contrast, no evidence of hepatotoxicity was observed in patients with g-HAT. Fexinidazole treatment results in a dose-dependent liver toxicity and transient bone marrow suppression in Chagas disease patients. Regimens of shorter duration should be evaluated in clinical trials with patients with Chagas disease. The currently recommended regimen for sleeping sickness provides exposures within a satisfactory safety margin for bone marrow suppression and does not cause hepatotoxicity.

Pharmacokinetics, Metabolism, and Excretion of [14C]Esaxerenone, a Novel Mineralocorticoid Receptor Blocker in Humans.

Esaxerenone (CS-3150) is a novel, nonsteroidal, selective mineralocorticoid receptor blocker. The absorption, metabolism, distribution, and excretion of esaxerenone were assessed in in vitro studies and in a clinical study, where [14C]esaxerenone (150 µCi/20 mg) was administered orally to six healthy male subjects. The plasma concentrations of esaxerenone and its metabolites (M4, M11, and M1) were measured using liquid chromatography-tandem mass spectrometry. The recovery of radioactivity was 92.5%, with 38.5% and 54.0% excreted in the urine and feces, respectively. The half-life of radioactivity in blood and plasma was approximately 30 hours, similar to that of the unchanged form in plasma. The blood-to-plasma ratio was 0.628, demonstrating low partitioning to blood components. In plasma, esaxerenone was the most abundant moiety (40.8%), followed by O-glucuronide (21.4%; M4), acyl-glucuronide of amide-bond hydrolysate (8.0%; M11), and the deshydroxyethyl form (1.7%; M1). In vitro studies showed that esaxerenone was a substrate of CYP3A and multiple UDP-glucuronosyltransferase isoforms. Oxidation contributed approximately 30% to its clearance, as indicated by the excretion ratio of oxidized metabolites into urine and feces. Caco-2 studies showed that esaxerenone was a substrate of P-glycoprotein and breast cancer resistance protein; however, the excretion ratios of the unchanged form in the feces and urine were 18.7% and 1.6%, respectively, indicating that these transporters were not important for the absorption and elimination of esaxerenone. Low urinary excretion of esaxerenone suggested that the plasma exposure of esaxerenone was not affected by renal dysfunction. Multiple elimination pathways including oxidation, glucuronidation, and hydrolysis, and the low contribution of transporters, indicated limited drug-drug interaction potential.

Clinical Pharmacokinetics of Anaplastic Lymphoma Kinase Inhibitors in Non-Small-Cell Lung Cancer.

The identification of anaplastic lymphoma kinase rearrangements in 2-5% of patients with non-small-cell lung cancer led to rapid advances in the clinical development of oral tyrosine kinase inhibitors. Anaplastic lymphoma kinase inhibitors are an effective treatment in preclinical models and patients with anaplastic lymphoma kinase-translocated cancers. Four anaplastic lymphoma kinase inhibitors (crizotinib, ceritinib, alectinib, and brigatinib) have recently been approved. Post-marketing studies provided additional pharmacokinetic information on their pharmacokinetic parameters. The pharmacokinetic properties of approved anaplastic lymphoma kinase inhibitors have been reviewed herein. Findings from additional studies on the effects of drug-metabolizing enzymes, drug transporters, and drug-drug interactions have been incorporated. Crizotinib, ceritinib, and alectinib reach their maximum plasma concentrations after approximately 6 h and brigatinib after 1-4 h. These drugs are primarily metabolized by cytochrome P450 3A with other cytochrome P450 enzymes. They are mainly excreted in the feces, with only a minor fraction being eliminated in urine. Crizotinib, ceritinib, and brigatinib are substrates for the adenosine triphosphate binding-cassette transporter B1, whereas alectinib is not. The different substrate specificities of the transporters play a key role in superior blood-brain barrier penetration by alectinib than by crizotinib and ceritinib. Although the absorption, distribution, and excretion of anaplastic lymphoma kinase inhibitors are regulated by drug transporters, their transporter-mediated pharmacokinetics have not yet been elucidated in detail in patients with non-small-cell lung cancer. Further research to analyze the contribution of drug transporters to the pharmacokinetics of anaplastic lymphoma kinase inhibitors in patients with non-small-cell lung cancer will be helpful for understanding the mechanisms of the inter-individual differences in the pharmacokinetics of anaplastic lymphoma kinase inhibitors.

Preclinical assessment of the ADME, efficacy and drug-drug interaction potential of a novel NAMPT inhibitor.

GNE-617 (N-(4-((3,5-difluorophenyl)sulfonyl)benzyl)imidazo[1,2-a]pyridine-6-carboxamide) is a potent, selective nicotinamide phosphoribosyltransferase (NAMPT) inhibitor being explored as a potential treatment for human cancers. Plasma clearance was low in monkeys and dogs (9.14 mL min-1 kg-1 and 4.62 mL min-1 kg-1, respectively) and moderate in mice and rats (36.4 mL min-1 kg-1 and 19.3 mL min-1 kg-1, respectively). Oral bioavailability in mice, rats, monkeys and dogs was 29.7, 33.9, 29.4 and 65.2%, respectively. Allometric scaling predicted a low clearance of 3.3 mL min-1 kg-1 and a volume of distribution of 1.3 L kg-1 in human. Efficacy (57% tumor growth inhibition) in Colo-205 CRC tumor xenograft mice was observed at an oral dose of 15 mg/kg BID (AUC = 10.4 µM h). Plasma protein binding was moderately high. GNE-617 was stable to moderately stable in vitro. Main human metabolites identified in human hepatocytes were formed primarily by CYP3A4/5. Transporter studies suggested that GNE-617 is likely a substrate for MDR1 but not for BCRP. Simcyp® simulations suggested a low (CYP2C9 and CYP2C8) or moderate (CYP3A4/5) potential for drug-drug interactions. The potential for autoinhibition was low. Overall, GNE-617 exhibited acceptable preclinical properties and projected human PK and dose estimates.

Bisphenol S modulates concentrations of bisphenol A and oestradiol in female and male mice.

Concern over endocrine-disrupting actions of bisphenol A (BPA) has prompted some manufacturers to remove it from consumer products. Among the chemical replacements in "BPA-free" products are other bisphenol analogues, such as bisphenol S (BPS). Given evidence that BPA and BPS possess similar oestrogenic activity, their capacity to interact and disrupt oestrogen homeostasis should be examined. We investigated whether BPS can modulate concentrations of 14C-BPA, exogenous 3H-oestradiol (E2), or natural E2. CF-1 mice were each given a single subcutaneous injection of oil containing 0 (vehicle), 1, 3, or 9 mg BPS, then given a dietary supplement containing either 50 µg/kg 14C-BPA or 5 µCi (14.5 ng) 3H-E2. BPS treatment elevated 14C-BPA concentrations in blood serum and certain reproductive organs of both sexes, but reduced 3H-E2 concentrations in blood serum of females. In another experiment, natural E2 was measured in urine 2-12 h after injection of 0 (vehicle), 1, or 3 mg BPS. BPS reduced E2 concentrations at 10 h after injection in both sexes. These results are consistent with evidence that BPS and BPA compete for access to metabolic enzymes, and that BPS can disrupt oestrogen homeostasis. These findings demonstrate the importance of considering multiple toxicants when determining regulatory exposure limits.

Cerdulatinib Pharmacodynamics and Relationships to Tumor Response Following Oral Dosing in Patients with Relapsed/Refractory B-cell Malignancies.

PURPOSE: Preclinical studies suggest SYK and JAK contribute to tumor-intrinsic and microenvironment-derived survival signals. The pharmacodynamics of cerdulatinib, a dual SYK/JAK inhibitor, and associations with tumor response were investigated. PATIENTS AND METHODS: In a phase I dose-escalation study in adults with relapsed/refractory B-cell malignancies, cerdulatinib was administered orally to sequential dose-escalation cohorts using once-daily or twice-daily schedules. The study enrolled 8 patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL), 13 with follicular lymphoma, 16 with diffuse large B-cell lymphoma (DLBCL), and 6 with mantle cell lymphoma. Correlation of tumor response with pharmacodynamic markers was determined in patients with meaningful clinical responses. RESULTS: Following cerdulatinib administration, complete SYK and JAK pathway inhibition was achieved in whole blood of patients at tolerated exposures. Target inhibition correlated with serum cerdulatinib concentration, and IC50 values against B-cell antigen receptor (BCR), IL2, IL4, and IL6 signaling pathways were 0.27 to 1.11 µmol/L, depending on the phosphorylation event. Significant correlations were observed between SYK and JAK pathway inhibition and tumor response. Serum inflammation markers were reduced by cerdulatinib, and several significantly correlated with tumor response. Diminished expression of CD69 and CD86 (B-cell activation markers), CD5 (negative regulator of BCR signaling), and enhanced expression of CXCR4 were observed in 2 patients with CLL, consistent with BCR and IL4 suppression and loss of proliferative capacity. CONCLUSIONS: Cerdulatinib potently and selectively inhibited SYK/JAK signaling at tolerated exposures in patients with relapsed/refractory B-cell malignancies. The extent of target inhibition in whole-blood assays and suppression of inflammation correlated with tumor response. (ClinicalTrials.gov ID:NCT01994382).

Quantitative Systems Toxicology Analysis of In Vitro Mechanistic Assays Reveals Importance of Bile Acid Accumulation and Mitochondrial Dysfunction in TAK-875-Induced Liver Injury.

TAK-875 (fasiglifam), a GPR40 agonist in development for the treatment of type 2 diabetes (T2D), was voluntarily terminated in Phase III trials due to adverse liver effects. The potential mechanisms of TAK-875 toxicity were explored by combining in vitro experiments with quantitative systems toxicology (QST) using DILIsym, a mathematical representation of drug-induced liver injury. In vitro assays revealed that bile acid transporters were inhibited by both TAK-875 and its metabolite, TAK-875-Glu. Experimental data indicated that human bile salt export pump (BSEP) inhibition by TAK-875 was mixed whereas sodium taurocholate co-transporting polypeptide (NTCP) inhibition by TAK-875 was competitive. Furthermore, experimental data demonstrated that both TAK-875 and TAK-875-Glu inhibit mitochondrial electron transport chain (ETC) enzymes. These mechanistic data were combined with a physiologically based pharmacokinetic (PBPK) model constructed within DILIsym to estimate liver exposure of TAK-875 and TAK-875-Glu. In a simulated population (SimPops) constructed to reflect T2D patients, 16/245 (6.5%) simulated individuals developed alanine aminotransferase (ALT) elevations, an incidence similar to that observed with 200 mg daily dosing in clinical trials. Determining the mode of bile acid transporter inhibition (Ki) was critical to accurate predictions. In addition, simulations conducted on a sensitive subset of individuals (SimCohorts) revealed that when either BSEP or ETC inhibition was inactive, ALT elevations were not predicted to occur, suggesting that the two mechanisms operate synergistically to produce the observed clinical response. These results demonstrate how utilizing QST methods to interpret in vitro experimental results can lead to an improved understanding of the clinically relevant mechanisms underlying drug-induced toxicity.

Design and Activity of Specific Hypoxia-Inducible Factor-2α (HIF-2α) Inhibitors for the Treatment of Clear Cell Renal Cell Carcinoma: Discovery of Clinical Candidate ( S)-3-((2,2-Difluoro-1-hydroxy-7-(methylsulfonyl)-2,3-dihydro-1 H-inden-4-yl)oxy)-5-fluorobenzonitrile (PT2385).

HIF-2α, a member of the HIF family of transcription factors, is a key oncogenic driver in cancers such as clear cell renal cell carcinoma (ccRCC). A signature feature of these cancers is the overaccumulation of HIF-2α protein, often by inactivation of the E3 ligase VHL (von Hippel-Lindau). Herein we disclose our structure based drug design (SBDD) approach that culminated in the identification of PT2385, the first HIF-2α antagonist to enter clinical trials. Highlights include the use of a putative n → π*Ar interaction to guide early analog design, the conformational restriction of an essential hydroxyl moiety, and the remarkable impact of fluorination near the hydroxyl group. Evaluation of select compounds from two structural classes in a sequence of PK/PD, efficacy, PK, and metabolite profiling identified 10i (PT2385, luciferase EC50 = 27 nM) as the clinical candidate. Finally, a retrospective crystallographic analysis describes the structural perturbations necessary for efficient antagonism.