Synthesis and Biological Evaluation of N-[2-(4-Hydroxyphenylamino)-pyridin-3-yl]-4-methoxy-benzenesulfonamide (ABT-751) Tricyclic Analogues as Antimitotic and Antivascular Agents with Potent in Vivo Antitumor Activity.

Benzopyridothiadiazepine (2a) and benzopyridooxathiazepine (2b) were modified to produce tricyclic quinazolinone 15-18 or benzothiadiazine 26-27 derivatives. These compounds were evaluated in cytotoxicity and tubulin inhibition assays and led to potent inhibitors of tubulin polymerization. N-[2(4-Methoxyphenyl)ethyl]-1,2-dihydro-pyrimidino[2,1-b]quinazolin-6-one (16a) exhibited the best in vitro cytotoxic activity (GI50 10-66.9 nM) against the NCI 60 human tumor cell line and significant potency against tubulin assembly (IC50 0.812 µM). In mechanism studies, 16a was shown to block cell cycle in G2/M phase and to disrupt microtubule formation and displayed good antivascular properties as inhibition of cell migration, invasion, and endothelial tube formation. Compound 16a was evaluated in C57BL/6 mouse melanoma B16F10 xenograft model to validate its antitumor activity, in comparison with reference ABT-751 (1). Compound 16a displayed strong in vivo antitumor and antivascular activities at a dose of 5 mg/kg without obvious toxicity, whereas 1 needed a 10-fold higher concentration to reach similar effects.

Interferon-free regimens containing setrobuvir for patients with genotype 1 chronic hepatitis C: a randomized, multicenter study.

BACKGROUND & AIMS: Setrobuvir is a direct-acting antiviral (DAA) non-nucleoside inhibitor of hepatitis C virus (HCV) polymerase. This study examined interferon-free combinations containing setrobuvir, a ritonavir-boosted protease inhibitor (danoprevir/r) and ribavirin, with/without the nucleoside inhibitor mericitabine in HCV genotype (G)1 patients. METHODS: Non-cirrhotic treatment-naïve patients (N = 110) were randomized to five groups. Three groups received a 14-day mericitabine/ribavirin lead-in followed by treatment with 3 DAAs (setrobuvir, danoprevir/r, mericitabine) plus ribavirin for 12 weeks (Group A: G1a; D: G1b) or 24 weeks (B: G1a), and two groups received 2 DAAs (setrobuvir, danoprevir/r) plus ribavirin for 12 weeks (E: G1b) or 24 weeks (C: G1a). Efficacy was defined as sustained virological response (HCV RNA <25 IU/ml after 12 weeks' follow-up, SVR12). RESULTS: Two groups met predefined futility criteria for breakthrough (C) or relapse (A) and were discontinued. SVR12 rates were 42.9% (3/7) and 74.1% (20/27) in G1a patients in Groups A and B, respectively, and 95.7% (22/23) and 68.2% (15/22) in G1b patients in Groups D and E respectively. All G1a patients assigned to 24 weeks of treatment who experienced a decrease in HCV RNA of ≥2.3 log10 IU by the end of the lead-in period (n = 28) achieved SVR12. Overall, treatment was well tolerated and most adverse events were mild to moderate. No major safety signals were identified. CONCLUSIONS: An interferon-free setrobuvir-based regimen (3 DAAs plus ribavirin) is safe and effective in treatment-naïve G1 patients.

Pharmacokinetics and pharmacodynamics of setrobuvir, an orally administered hepatitis C virus non-nucleoside analogue inhibitor.

PURPOSE: New antiviral agents with activity against hepatitis C virus (HCV) are needed to optimize treatment for chronic hepatitis C (CHC). We evaluated the pharmacokinetics of setrobuvir (a non-nucleoside HCV polymerase inhibitor) in healthy volunteers (study 1 & 2) and its antiviral efficacy in patients with genotype 1, noncirrhotic treatment-naive CHC (study 3). METHODS: Three studies investigated the pharmacokinetics and pharmacodynamics of setrobuvir. First, sequential cohorts of volunteers were randomly assigned to receive single oral doses of setrobuvir 400 to 3000 mg or placebo in a double-blind, ascending dose study. In the second study, volunteers were randomly assigned to receive multiple doses of setrobuvir (400 or 800 mg once daily [QD] or 600 mg twice a day [BID]). In the third study, patients with genotype 1 CHC received setrobuvir (200, 400, or 800 mg) or placebo BID for 3 days. FINDINGS: After single doses of setrobuvir (400-3000 mg) to volunteers in a fasted state, peak Cmax and AUC0-∞ increased in a less than dose-proportional manner. The mean apparent t½z ranged from 22.0 to 31.3 hours and was not dose related. Cmax and AUC increased significantly (4.3- and 6.3-fold, respectively) in volunteers who received 2000 mg with a high-fat meal versus fasting. After multiple oral doses, steady state was achieved after 7 days of dosing (400 or 800 mg QD and 600 mg BID) and accumulation was dose-independent. Mean day 14 plasma exposure increased in a less than dose-proportional manner in volunteers who received 400 and 800 mg QD, but it was more than dose-proportional in volunteers receiving 600 mg BID. Dose did not affect the mean t½z (range, 24.1-26.6 hours), apparent oral clearance (0.254-0.516 L/h), or apparent volume of distribution (9.60-18.1 L). In patients with CHC, dose-related reductions in HCV RNA concentration were apparent within 24 hours of the start of treatment. Reductions from baseline to the end of treatment (day 3) in patients treated with setrobuvir 200, 400, and 800 mg BID were -2.1, -2.2, and -2.9 log10 IU/mL, respectively (vs ≤0.1 log10 IU/mL with placebo). Reductions in HCV RNA were greater in patients with genotype 1b (range, -2.7 to -3.1 log10 IU/mL) than in patients with genotype 1a (range, -1.3 to -2.7 log10 IU/mL). Setrobuvir was well tolerated, with no serious adverse events. IMPLICATIONS: The steady state pharmacokinetics of setrobuvir appear to be dose proportional, and setrobuvir produces a mean reduction of 2.9 log10 IU/mL in HCV RNA over 3 days in patients with genotype 1 (a and b) treated with 800 mg BID. ClinicalTrials.gov identifier: NCT00782353.

Rational drug repositioning guided by an integrated pharmacological network of protein, disease and drug.

BACKGROUND: The process of drug discovery and development is time-consuming and costly, and the probability of success is low. Therefore, there is rising interest in repositioning existing drugs for new medical indications. When successful, this process reduces the risk of failure and costs associated with de novo drug development. However, in many cases, new indications of existing drugs have been found serendipitously. Thus there is a clear need for establishment of rational methods for drug repositioning. RESULTS: In this study, we have established a database we call "PharmDB" which integrates data associated with disease indications, drug development, and associated proteins, and known interactions extracted from various established databases. To explore linkages of known drugs to diseases of interest from within PharmDB, we designed the Shared Neighborhood Scoring (SNS) algorithm. And to facilitate exploration of tripartite (Drug-Protein-Disease) network, we developed a graphical data visualization software program called phExplorer, which allows us to browse PharmDB data in an interactive and dynamic manner. We validated this knowledge-based tool kit, by identifying a potential application of a hypertension drug, benzthiazide (TBZT), to induce lung cancer cell death. CONCLUSIONS: By combining PharmDB, an integrated tripartite database, with Shared Neighborhood Scoring (SNS) algorithm, we developed a knowledge platform to rationally identify new indications for known FDA approved drugs, which can be customized to specific projects using manual curation. The data in PharmDB is open access and can be easily explored with phExplorer and accessed via BioMart web service (http://www.i-pharm.org/, http://biomart.i-pharm.org/).

Insight into the structural requirements of benzothiadiazine scaffold-based derivatives as hepatitis C virus NS5B polymerase inhibitors using 3D-QSAR, molecular docking and molecular dynamics.

Hepatitis C virus (HCV) infection is a significant world health threat with frequently ineffective problem existed in the present treatment, thus representing a major unmet medical need. The nonstructural viral protein 5B (NS5B), one of the best-studied polymerase, has emerged as an attractive target for the development of novel therapeutics against hepatitis C virus. In this work, both ligand- and receptor- based three-dimensional quantitative structure activity relationship (3D-QSAR) studies were carried out using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) techniques on 360 benzothiadiazine scaffold-based derivatives as HCV GT-1b NS5B polymerase allosteric inhibitors. The resultant optimum 3D-QSAR model exhibited R(2)(ev) of 0.54, R(2)(nev) of 0.72 and the predictive ability was validated by using an independent test set of 90 compounds which gave R(2)(pred) value of 0.64. In addition, docking analysis and molecular dynamics simulation (MD) were also applied to elucidate the probable binding modes of these inhibitors at the allosteric site of the enzyme. Interpretation of the 3D contour maps in context of the topology of the allosteric binding site of NS5B provided insight into NS5B-inhibitor interactions. The information obtained from this work can be utilized to accurately predict the binding affinity of related analogues and also facilitate the future rational design of novel inhibitors with improved activity.

Recent advances in drug discovery of benzothiadiazine and related analogs as HCV NS5B polymerase inhibitors.

Hepatitis C virus (HCV) is a major health burden, with an estimated 170 million chronically infected individuals worldwide, and a leading cause of liver transplantation. Patients are at increased risk of developing liver cirrhosis, hepatocellular carcinoma and even liver failure. In the past two decades, several approaches have been adopted to inhibit non-structural viral proteins. The RNA-dependent RNA polymerase (NS5B) of HCV is one of the attractive validated targets for development of new drugs to block HCV infection. In this review, we report the recent progress made towards identifying and developing benzothiadiazines as HCV NS5B polymerase inhibitors. The substituted benzothiadiazine class was identified by HTS in 2002 as an NS5B inhibitor. Further optimization and modification of the core has improved the potency and pharmacokinetic properties of substituted benzothiadiazines. Research on palm site-binding benzothiadiazine analogs and related derivatives and analogs is discussed in this article.

S 18986 reverses spatial working memory impairments in aged mice: comparison with memantine.

RATIONALE: Normal or pathological ageing is characterized by working-memory dysfunction paired with a marked reduction in several neurotransmitters activity. The development of therapeutic strategy centered on the glutamatergic system known to bear a critical role in cognitive functions, is therefore of major importance in the treatment of mild forms of AD or age-related memory dysfunctions. OBJECTIVES: In Experiment 1, we investigated the effects of ageing on spatial working memory measured by sequential alternation (SA). Thus, the decay of alternation rates over a series of trials separated by varying intertrial temporal intervals (ITI, from 5 sec to 180 sec) was studied in mice of different age groups. In Experiment 2, we investigated the memory-enhancing potential of S 18986--a modulator of AMPA receptors--on age-related SA impairments, in comparison with memantine--an antagonist of NMDA receptors--. RESULTS: In Experiment 1, aged mice responded at chance with shorter ITI's and exhibited greater levels of interference in the SA task as compared to young adult mice. In Experiment 2, (1) S 18986 at 0.03 and 0.1 mg/kg reversed the memory deficit in aged mice but did not modify performance in young adult mice; (2) memantine at 10 mg/kg also increased SA rates in aged mice but did not improve performance in young adult mice. CONCLUSION: The SA task is a useful tool to reveal age-induced time-dependent working memory impairments. As compared to memantine, S 18986--a compound targeting AMPA receptors--contributes a valuable therapy in the treatment of age-related cognitive dysfunctions or mild forms of AD.

DRUG FOCUS: S 18986: A positive allosteric modulator of AMPA-type glutamate receptors pharmacological profile of a novel cognitive enhancer.

Alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) type glutamate receptors are critical for synaptic plasticity and induction of long-term potentiation (LTP), considered as one of the synaptic mechanisms underlying learning and memory. Positive allosteric modulators of AMPA receptors could provide a therapeutic approach to the treatment of cognitive disorders resulting from aging and/or neurodegenerative diseases, such as Alzheimer disease (AD). Several AMPA potentiators have been described in the last decade, but for the moment their clinical efficacy has not been demonstrated due to the complexity of the target, AMPA receptors, and the difficulty in studying cognition in animals and humans. A better understanding of the mechanism of action of this type of drug remains an important issue, if knowledge of these compounds is to be increased and if this novel therapeutic approach is to be an interesting research area. Among the AMPA potentiators, S 18986 is emerging as a new selective positive allosteric modulator of AMPA-type glutamate receptors. S 18986, as with other positive AMPA receptor modulators, increased induction and maintenance of LTP in the hippocampus as well as the expression of brain-derived neurotrophic factor (BDNF) both in vitro and in vivo. Its cognitive-enhancing properties have been demonstrated in various behavioral models (procedural, spatial, "episodic," working, and relational/declarative memory) in young-adult and aged rodents. It is interesting to note that memory-enhancing effects appeared more robust in middle-aged animals compared with aged ones and in "episodic" and spatial memory tasks. From these results, S 18986 is expected to treat memory deficits associated with early cerebral aging and neurological diseases in elderly people.

Anti-tubercular agents. Part 5: synthesis and biological evaluation of benzothiadiazine 1,1-dioxide based congeners.

In an effort to discover new and effective chemotherapeutic agents from this laboratory for the treatment of tuberculosis, here in we describe the synthesis and biological evaluation of a series of novel benzothiadiazine 1,1-dioxide (BTD) based congeners by using rifampicin, streptomycin; ciprofloxacin and amphotericin as positive controls. Further, to understand structural requirements for exploring the structure activity relationship of BTDs, cytotoxicity and in vivo study of recently reported potent molecule 4 (MIC = 1 microg/mL) is also discussed.

Search for new and novel chemotherapeutics for the treatment of human malignancies.

One of the hallmarks of cancer is the uncontrolled cell proliferation which causes more deaths among the human diseases throughout the globe. One in eight deaths worldwide are due to cancer, it is the second and third leading cause of death in economically developed and developing countries, respectively. As it is caused by both external and internal factors, a balanced approach to cancer control includes prevention, early detection, and effective treatment. In the treatment of cancer, chemotherapy is one of the practical methods and is widely used employing drugs that can destroy cancer cells by impeding their growth and reproduction. Despite the great strides made in the treatment of cancer over the past 50 years, it continues to be a major health concern and therefore, extensive efforts have been devoted to search for new scaffolds to develop chemotherapeutics. In this perspective, over the past two decades from this laboratory extensive efforts have been made in the development of new chemotherapeutic agents for the treatment of cancer. In this review, glimpses on types of current chemotherapeutic agents based on their action of inhibition and the new molecules that are being developed based on the scaffolds such as pyrrolo[2,1-c][1,4]benzodiazepines, podophyllotoxins, benzothiadiazine 1,1-dioxides, naphthalimides and monastrol across the world as well as in this laboratory have been articulated.

Activity of a potent hepatitis C virus polymerase inhibitor in the chimpanzee model.

A-837093 is a potent and specific nonnucleoside inhibitor of the hepatitis C virus (HCV) nonstructural protein 5B (NS5B) RNA-dependent RNA polymerase. It possesses nanomolar potencies in both enzymatic and replicon-based cell culture assays. In rats and dogs this compound demonstrated an oral plasma half-life of greater than 7 h, and its bioavailability was >60%. In monkeys it had a half-life of 1.9 h and 15% bioavailability. Its antiviral efficacy was evaluated in two chimpanzees infected with HCV in a proof-of-concept study. The design included oral dosing of 30 mg per kg of body weight twice a day for 14 days, followed by a 14-day posttreatment observation. Maximum viral load reductions of 1.4 and 2.5 log(10) copies RNA/ml for genotype 1a- and 1b-infected chimpanzees, respectively, were observed within 2 days after the initiation of treatment. After this initial drop in the viral load, a rebound of plasma HCV RNA was observed in the genotype 1b-infected chimpanzee, while the genotype 1a-infected chimpanzee experienced a partial rebound that lasted throughout the treatment period. Clonal analysis of NS5B gene sequences derived from the plasma of A-837093-treated chimpanzees revealed the presence of several mutations associated with resistance to A-837093, including Y448H, G554D, and D559G in the genotype 1a-infected chimpanzee and C316Y and G554D in the genotype 1b-infected chimpanzee. The identification of resistance-associated mutations in both chimpanzees is consistent with the findings of in vitro selection studies, in which many of the same mutations were selected. These findings validate the antiviral efficacy and resistance development of benzothiadiazine HCV polymerase inhibitors in vivo.

Towards selective Kir6.2/SUR1 potassium channel openers, medicinal chemistry and therapeutic perspectives.

ATP sensitive potassium (K(ATP)) channels have important functions in neuroendocrine tissue, in smooth and skeletal muscle and in the heart. In pancreatic beta cells the K(ATP) channels, which are formed by 4 ion channels (Kir6.2) and 4 regulatory sulfonylurea receptors (SUR1), control the glucose stimulated release of insulin. The Kir6.2/SUR1 K(ATP) channels are also present in the brain and in other neuroendocrine tissues. Blockers of Kir6.2/SUR1 channels, e.g. glibenclamide and repaglinide stimulate release of insulin and are used for treatment of type 2 diabetes. Openers of Kir6.2/SUR1 channels, e.g. diazoxide, have in contrast only found limited clinical use in treatment of hypersecretion of insulin associated with certain tumours (insulinoma) and genetic disorders (persistent hyperinsulinemia and hypoglycemia of infancy, PHHI). Recent studies have however, indicated that openers of Kir6.2/SUR1 channels could be useful in treatment of e.g. metabolic disorders and diseases of the CNS. The clinical use of diazoxide has been hampered by its lack of potency and selectivity giving rise to side effects, such as oedema and hirsutism and new selective openers of Kir6.2/SUR1 channels have been pursued. This has provided several structurally diverse series, which include 1,2,4-thiadiazine 1,1-dioxide derivatives, like BPDZ 62, BPDZ 73, NNC 55-0462, NNC 55-0118 and NN414, cyanoguanidines, nitropyrazoles and 4-sulfamoylphenylbenzamides. NN414 has been shown to be a potent and Kir6.2/SUR1 selective K(ATP) channels opener, which inhibits glucose stimulated insulin release in vitro and in vivo and which has beneficial effects on glucose homeostasis in preclinical and clinical studies.

S 18986, a positive modulator of AMPA receptors with cognition-enhancing properties, increases ACh release in the hippocampus of young and aged rat.

The effect of S 18986, positive AMPA receptor modulator, on acetylcholine (ACh), gamma-aminobutyric acid (GABA) and glutamate (Glu) release from the hippocampus of freely moving young and aged rats was investigated by microdialysis coupled to HPLC. The cognition-enhancing properties were evaluated by a passive avoidance test. In 3 month-old rats, S 18986 (10 mg/kg i.p.) increased by 70% ACh release, which returned to basal level within 2 h, while 3 mg/kg had no effect. In 22 month-old rats, both 3 and 10 mg/kg i.p. induced a long lasting increase in ACh release, as large as that induced by 10 mg/kg in young rats. S 18986 did not modify GABA and glutamate release. No effect on general behavior was observed, but S 18986 at both doses prevented the disrupting effect of scopolamine (1 mg/kg i.p.) on passive avoidance acquisition.

Long-term metabolic effects of spironolactone and thiazides combined with potassium-sparing agents for treatment of essential hypertension.

By using information prospectively collected in the computerized ARTEMIS databank, the long-term metabolic consequences of spironolactone, hydrochlorothiazide-amiloride combination and cyclothiazide-triamterene combination were evaluated in 100 patients for each group matched according to sex, age and blood pressure (BP). Spironolactone was prescribed at a mean dose of 98 mg, hydrochlorothiazide at 36 mg and cyclothiazide at 2 mg, during a mean follow-up of 20 months. Compared with the pretherapeutic values, BP decreased equally in both treatment groups (18/9 mm Hg on average). Creatinine increased significantly in the 3 groups (9, 8, 14 mumol/liter, p less than 0.001) as did uric acid (18, 31, 42 mumol, p less than 0.001). Plasma potassium increased with spironolactone (0.7 mmol/liter, p less than 0.001) and remained stable with the combinations of the thiazide-potassium-sparing agents. For the 3 groups, the slight and nonsignificant variations of fasting blood glucose and cholesterol were mainly the results of a phenomenon of regression to the mean. However, when both groups of thiazide-treated patients were considered, the reduction of plasma potassium was accompanied by a slight increase in glucose (0.1 mmol/liter) and cholesterol levels (0.2 mmol/liter) compared with when kalemia decreased (-0.1 and -0.1 mmol/liter, respectively, p less than 0.05 and p less than 0.05). It is concluded that in a clinical daily practice of a hypertension clinic low doses of spironolactone or of thiazides combined with potassium-sparing agents reduced BP without alteration in lipid or carbohydrate metabolism on long-term follow-up.

Comparison of cyclothiazide and hydrochlorthiazide in hypertension. Effects of different doses of diuretics.

In a group of 12 hypertensive outpatients, randomized double-blind cross-over comparison of the antihypertensive effect of various doses of cyclothiazide and hydrochlorthiazide revealed that 2.5 mg of cyclothiazide daily or 25 mg of hydrochlorthiazide daily have an equal antihypertensive effect. Increasing the dose of either diuretic did not further reduce the blood pressure.

[Cystic teratoma of the diaphragm. Apropos of a case, review of the literature]. / Tératome kystique du diaphragme. A propos d'un cas, revue de la littérature.

Benign tumors of the diaphragm are rare lesions. The cystic teratoma of this muscle is an internal axial tumor, a benign dysembryoma, and only 4 cases could be found in the published literature. The cystic teratoma reported was discovered fortuitously during investigation of hypertension. It was located in the diaphragm above the psoas arch.