Experience and impact of stigma in people with chronic hepatitis B: a qualitative study in Asia, Europe, and the United States.

BACKGROUND: People with chronic hepatitis B (CHB) commonly experience social and self-stigma. This study sought to understand the impacts of CHB-related stigma and a functional cure on stigma. METHODS: Adults with CHB with a wide range of age and education were recruited from 5 countries and participated in 90-minute qualitative, semi-structured interviews to explore concepts related to CHB-associated stigma and its impact. Participants answered open-ended concept-elicitation questions regarding their experience of social and self-stigma, and the potential impact of reduced CHB-related stigma. RESULTS: Sixty-three participants aged 25 to 71 years (15 from the United States and 12 each from China, Germany, Italy, and Japan) reported emotional, lifestyle, and social impacts of living with CHB, including prejudice, marginalization, and negative relationship and work experiences. Self-stigma led to low self-esteem, concealment of CHB status, and social withdrawal. Most participants stated a functional cure for hepatitis B would reduce self-stigma. CONCLUSIONS: CHB-related social and self-stigma are widely prevalent and affect many aspects of life. A functional cure for hepatitis B may reduce social and self-stigma and substantially improve the health-related quality of life of people with CHB. Incorporating stigma into guidelines along with infectivity considerations may broaden the patient groups who should receive treatment.

Medication Adherence of People Living with HIV in Japan-A Cross-Sectional Study.

Long-term medical care for people living with HIV (PLHIV) is critical for treatment efficacy, and various studies have examined reasons for antiretroviral therapy (ART) non-adherence. In Japan, doctors assume patients maintain high adherence. However, little is known about real-world treatment adherence. We conducted an anonymous self-administered web-based survey asking about adherence for a total of 1030 Japanese PLHIV who were currently on ART. Adherence was determined using the eight-item Morisky Medication Adherence Scale (MMAS-8), for which scoring ranged from 0 to 8 and scores < 6 points were classified as low adherence. Data were analyzed based on patient-related factors; therapy-related factors; condition-related factors, such as a comorbidity with depression (utilizing the Patient Health Questionnaire 9, PHQ-9); and healthcare/system-related factors. Among 821 PLHIV who responded to the survey, 291 responders (35%) were identified as being in the low adherence group. A statistically significant relationship was found between the number of missed anti-HIV drug doses within the previous 2 weeks and long-term adherence, per the MMAS-8 score (p < 0.001). Risk factors for low adherence included age (younger than 21 years, p = 0.001), moderate to severe depression (p = 0.002, using the PHQ-9), and drug dependence (p = 0.043). Adherence was also influenced by a shared decision-making process, including treatment selection, doctor-patient relations, and treatment satisfaction. Adherence was mainly affected by treatment decision factors. Hence, support of care providers should be considered critical for improving adherence.

Synthesis and biological evaluation of novel selective androgen receptor modulators (SARMs) Part III: Discovery of 4-(5-oxopyrrolidine-1-yl)benzonitrile derivative 2f as a clinical candidate.

We previously reported that 4-(pyrrolidin-1-yl)benzonitrile derivative 1b was a selective androgen receptor modulator (SARM) that exhibited anabolic effects on organs such as muscles and the central nervous system (CNS), but neutral effects on the prostate. From further modification, we identified that 4-(5-oxopyrrolidine-1-yl)benzonitrile derivative 2a showed strong AR binding affinity with improved metabolic stabilities. Based on these results, we tried to enhance the AR agonistic activities by modifying the substituents of the 5-oxopyrrolidine ring. As a consequence, we found that 4-[(2S,3S)-2-ethyl-3-hydroxy-5-oxopyrrolidin-1-yl]-2-(trifluoromethyl)benzonitrile (2f) had ideal SARM profiles in Hershberger assay and sexual behavior induction assay. Furthermore, 2f showed good pharmacokinetic profiles in rats, dogs, monkeys, excellent nuclear selectivity and acceptable toxicological profiles. We also determined its binding mode by obtaining the co-crystal structures with AR.

Synthesis and biological evaluation of novel selective androgen receptor modulators (SARMs). Part II: Optimization of 4-(pyrrolidin-1-yl)benzonitrile derivatives.

We recently reported a class of novel tissue-selective androgen receptor modulators (SARMs), represented by a naphthalene derivative A. However, their pharmacokinetic (PK) profiles were poor due to low metabolic stability. To improve the PK profiles, we modified the hydroxypyrrolidine and benzonitrile substituents of 4-(pyrrolidin-1-yl)benzonitrile derivative B, which had a comparable potency as that of compound A. This optimization led us to further modifications, which improved metabolic stability while maintaining potent androgen agonistic activity. Among the synthesized compounds, (2S,3S)-2,3-dimethyl-3-hydroxylpyrrolidine derivative 1c exhibited a suitable PK profile and improved metabolic stability. Compound 1c demonstrated significant efficacy in levator ani muscle without increasing the weight of the prostate in an in vivo study. In addition, compound 1c showed agonistic activity in the CNS, which was detected using sexual behavior induction assay.

Discovery of 6-[5-(4-fluorophenyl)-3-methyl-pyrazol-4-yl]-benzoxazin-3-one derivatives as novel selective nonsteroidal mineralocorticoid receptor antagonists.

In the course of our study on selective nonsteroidal mineralocorticoid receptor (MR) antagonists, a series of novel benzoxazine derivatives possessing an azole ring as the core scaffold was designed for the purpose of attenuating the partial agonistic activity of the previously reported dihydropyrrol-2-one derivatives. Screening of alternative azole rings identified 1,3-dimethyl pyrazole 6a as a lead compound with reduced partial agonistic activity. Subsequent replacement of the 1-methyl group of the pyrazole ring with larger lipophilic side chains or polar side chains targeting Arg817 and Gln776 increased MR binding activity while maintaining the agonistic response at the lower level. Among these compounds, 6-[1-(2,2-difluoro-3-hydroxypropyl)-5-(4-fluorophenyl)-3-methyl-1H-pyrazol-4-yl]-2H-1,4-benzoxazin-3(4H)-one (37a) showed highly potent in vitro activity, high selectivity versus other steroid hormone receptors, and good pharmacokinetic profiles. Oral administration of 37a in deoxycorticosterone acetate-salt hypertensive rats showed a significant blood pressure-lowering effect with no signs of antiandrogenic effects.

Design, synthesis, and structure-activity relationships of dihydrofuran-2-one and dihydropyrrol-2-one derivatives as novel benzoxazin-3-one-based mineralocorticoid receptor antagonists.

Dihydrofuran-2-one and dihydropyrrol-2-one derivatives were identified as novel, potent and selective mineralocorticoid receptor (MR) antagonists by the structure-based drug design approach utilizing the crystal structure of MR/compound complex. Introduction of lipophilic substituents directed toward the unfilled spaces of the MR and identification of a new scaffold, dihydropyrrol-2-one ring, led to potent in vitro activity. Among the synthesized compounds, dihydropyrrol-2-one 11i showed an excellent in vitro activity (MR binding IC50=43nM) and high selectivity over closely related steroid receptors such as the androgen receptor (AR), progesterone receptor (PR) and glucocorticoid receptor (GR) (>200-fold for AR and PR, 100-fold for GR).

Design and synthesis of pyrrolo[3,2-d]pyrimidine human epidermal growth factor receptor 2 (HER2)/epidermal growth factor receptor (EGFR) dual inhibitors: exploration of novel back-pocket binders.

To develop novel human epidermal growth factor receptor 2 (HER2)/epidermal growth factor receptor (EGFR) kinase inhibitors, we explored pyrrolo[3,2-d]pyrimidine derivatives bearing bicyclic fused rings designed to fit the back pocket of the HER2/EGFR proteins. Among them, the 1,2-benzisothiazole (42m) ring was selected as a suitable back pocket binder because of its potent HER2/EGFR binding and cell growth inhibitory (GI) activities and pseudoirreversibility (PI) profile as well as good bioavailability (BA). Ultimately, we arrived at our preclinical candidate 51m by optimization of the N-5 side chain to improve CYP inhibition and metabolic stability profiles without a loss of potency (HER2/EGFR inhibitory activity, IC(50), 0.98/2.5 nM; and GI activity BT-474 cells, GI(50), 2.0 nM). Reflecting the strong in vitro activities, 51m exhibited potent tumor regressive efficacy against both HER2- and EGFR-overexpressing tumor (4-1ST and CAL27) xenograft models in mice at oral doses of 50 mg/kg and 100 mg/kg.

Identification of benzoxazin-3-one derivatives as novel, potent, and selective nonsteroidal mineralocorticoid receptor antagonists.

Mineralocorticoid receptor (MR) blockade has come into focus as a promising approach for the treatment of cardiovascular diseases such as hypertension and congestive heart failure. In order to identify a novel class of nonsteroidal MR antagonists that exhibit significant potency and good selectivity over other steroidal hormone receptors, we designed a novel series of benzoxazin-3-one derivatives and synthesized them from 6-(7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-6-yl)-2H-1,4-benzoxazin-3(4H)-one (1a), high-throughput screening (HTS) hit compound. Our design was based on a crystal structure of an MR/compound complex and a docking model. In the course of lead generation from 1a, a 1,2-diaryl framework was characterized as a key structure with high binding affinity. On the basis of scaffold hopping and optimization studies, benzoxazin-3-one derivatives possessing 1-phenyl-3-trifluoromethylpyrazol-5-yl moiety at the 6-position were identified as a novel series of potent and selective MR antagonists. Among these compounds, 6-[1-(4-fluoro-2-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-5-yl]-2H-1,4-benzoxazin-3(4H)-one (14n) showed highly potent activity and good selectivity and also exhibited a significant antihypertensive effect in deoxycorticosterone acetate-salt hypertensive rats. On the basis of these results, compound 14n was progressed for further pharmacological evaluation.

Design and synthesis of novel human epidermal growth factor receptor 2 (HER2)/epidermal growth factor receptor (EGFR) dual inhibitors bearing a pyrrolo[3,2-d]pyrimidine scaffold.

Dual inhibitors of human epidermal growth factor receptor 2 (HER2) and epidermal growth factor receptor (EGFR) have been investigated for breast, lung, gastric, prostate, and other cancers; one, lapatinib, is currently approved for breast cancer. To develop novel HER2/EGFR dual kinase inhibitors, we designed and synthesized pyrrolo[3,2-d]pyrimidine derivatives capable of fitting into the receptors' ATP binding site. Among the prepared compounds, 34e showed potent HER2 and EGFR (HER1) inhibitory activities as well as tumor growth inhibitory activity. The X-ray cocrystal structures of 34e with both HER2 and EGFR demonstrated that 34e interacts with the expected residues in their respective ATP pockets. Furthermore, reflecting its good oral bioavailability, 34e exhibited potent in vivo efficacy in HER2-overexpressing tumor xenograft models. On the basis of these findings, we report 34e (TAK-285) as a promising candidate for clinical development as a novel HER2/EGFR dual kinase inhibitor.

Structural analysis of the mechanism of inhibition and allosteric activation of the kinase domain of HER2 protein.

Aberrant signaling of ErbB family members human epidermal growth factor 2 (HER2) and epidermal growth factor receptor (EGFR) is implicated in many human cancers, and HER2 expression is predictive of human disease recurrence and prognosis. Small molecule kinase inhibitors of EGFR and of both HER2 and EGFR have received approval for the treatment of cancer. We present the first high resolution crystal structure of the kinase domain of HER2 in complex with a selective inhibitor to understand protein activation, inhibition, and function at the molecular level. HER2 kinase domain crystallizes as a dimer and suggests evidence for an allosteric mechanism of activation comparable with previously reported activation mechanisms for EGFR and HER4. A unique Gly-rich region in HER2 following the α-helix C is responsible for increased conformational flexibility within the active site and could explain the low intrinsic catalytic activity previously reported for HER2. In addition, we solved the crystal structure of the kinase domain of EGFR in complex with a HER2/EGFR dual inhibitor (TAK-285). Comparison with previously reported inactive and active EGFR kinase domain structures gave insight into the mechanism of HER2 and EGFR inhibition and may help guide the design and development of new cancer drugs with improved potency and selectivity.

The essential role of C-terminal residues in regulating the activity of hepatitis C virus RNA-dependent RNA polymerase.

We have previously determined the crystal structure of a non-structural 5B (NS5B) protein, an RNA-dependent RNA polymerase (RdRp) of hepatitis C virus (HCV). NS5B protein with the hydrophobic C-terminal 21 amino acid residues truncated, designated NS5B(570), shows a typical nucleotide polymerase structure resembling a right-hand shape. In the crystal structure, a C-terminal region between Leu545 and His562 occupies a putative RNA-binding cleft of this polymerase and seems to inhibit the polymerase activity. Varieties of recombinant NS5B proteins (NS5B(552), NS5B(544), NS5B(536) or NS5B(531), with C-terminal 39, 47, 55 or 60 amino acid residues truncated, respectively) were systematically constructed to elucidate effects of the region on the polymerase activity. NS5B(544), NS5B(536) and NS5B(531) showed markedly higher RdRp activities compared to the activities of NS5B(570) or NS5B(552). Furthermore, when the hydrophobic amino acid residues Leu547, Trp550 and Phe551 (LWF) in NS5B(570) and NS5B(552) were changed to alanine, their activities were higher than that of the original NS5B(570). The crystal structures of the various recombinant NS5B proteins were also determined. Structural comparison of the NS5B proteins indicates that the activation was caused by elimination of a unique hydrophobic interaction between the three C-terminal residues and a shallowly concave pocket consisting of thumb and palm domains.