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Tommy Tsang Cheung,1,* Tu H Mai,2,* Yen Lin Chia,2 Desmond YH Yap,1 Chi-Ho Lee,1 Cecil Chi-Keung Chen,2 Ying Huang,3 Yuwen Jin,3 James Johnston,4 Viktoria Werkström,5 Yuhui Yao,6 Xiaoyun Ge,7 Wenying Zheng8 1Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, People’s Republic of China; 2Clinical Pharmacology and Quantitative Pharmacology, Clinical Pharmacology & Safety Sciences, BioPharmaceuticals R&D, AstraZeneca, South San Francisco, CA, USA; 3Clinical Pharmacology, R&D China, AstraZeneca, Shanghai, People’s Republic of China; 4Late-stage Development, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK; 5Late-Stage Development, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden; 6Respiratory & Immunology, R&D China, AstraZeneca, Shanghai, People’s Republic of China; 7Clinical Safety, R&D China, AstraZeneca, Shanghai, People’s Republic of China; 8Biometrics, R&D China, AstraZeneca, Shanghai, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yen Lin Chia, Clinical Pharmacology and Quantitative Pharmacology, Clinical Pharmacology & Safety Sciences, BioPharmaceuticals R&D, AstraZeneca, 701 Gateway Blvd, South San Francisco, CA, 9408, USA, Tel +1 425 5272574, Email yenlin@gmail.comPurpose: Biological therapies targeting eosinophils have been shown to be effective in treating patients with severe eosinophilic asthma. Benralizumab (Fasenra®, AstraZeneca) is a humanized monoclonal antibody binding to the alpha subunit of the interleukin-5 receptor, which rapidly depletes eosinophils via antibody-dependent cellular cytotoxicity. The aim of this Phase 1 study was to assess the safety, tolerability, and pharmacokinetics of benralizumab in healthy Chinese individuals.Materials and Methods: In this randomized, single-blind study (NCT03928262), healthy Chinese adult participants aged 18 to 45 years, weighing 50 to 100 kg, were randomized 1:1:1 to receive a single subcutaneous (SC) injection of benralizumab 10 mg, 30 mg, or 100 mg in the upper arms on Day 1. Safety was monitored throughout the study (up to Day 85), and blood samples were taken to determine serum benralizumab concentrations and for detection of anti-drug antibody. A non-compartmental analysis was conducted to estimate the pharmacokinetic parameters.Results: Thirty-six healthy participants were enrolled, 12 in each dose group (mean [SD] age 26 [6] years). Following a single SC injection of benralizumab, 13 adverse events were reported by 10 participants (28%), with one mild injection-site reaction assessed as related. The mean serum benralizumab concentrations increased in a dose proportional manner, followed by exponential decreases. The mean terminal half-lives were 15.1 days for the 10 mg dose, 14.4 days for the 30 mg dose, and 15.4 days for the 100 mg dose. All doses resulted in near-complete depletion of eosinophils on Day 2, which was maintained throughout the study to Day 85.Conclusion: A single SC injection of benralizumab was well tolerated by healthy Chinese participants, with no new or unexpected safety findings. The pharmacokinetics of benralizumab in Chinese participants was dose-proportional and consistent with those of non-Chinese participants observed in previous studies.Clinical Trial Registration: NCT03928262 (https://clinicaltrials.gov/ct2/show/NCT03928262)Keywords: benralizumab, pharmacokinetics, healthy Chinese

Background: Benralizumab induces rapid and near-complete depletion of eosinophils from blood and lung tissue. We investigated whether benralizumab could attenuate the allergen-induced late asthmatic response (LAR) in participants with allergic asthma., Methods: Participants with allergic asthma who demonstrated increased sputum eosinophils and LAR at screening were randomised to benralizumab 30 mg or matched placebo given every 4 weeks for 8 weeks (3 doses). Allergen challenges were performed at weeks 9 and 12 when blood, sputum, bone marrow and bronchial tissue eosinophils and LAR were assessed., Results: 46 participants (mean age 30.9 years) were randomised to benralizumab (n=23) or placebo (n=23). Eosinophils were significantly reduced in the benralizumab group compared with placebo in blood at 4 weeks and sputum and bone marrow at 9 weeks after treatment initiation. At 7 h after an allergen challenge at week 9, sputum eosinophilia was significantly attenuated in the benralizumab group compared to placebo (least squares mean difference -5.81%, 95% CI -10.69- -0.94%; p=0.021); however, the LAR was not significantly different (least squares mean difference 2.54%, 95% CI 3.05-8.12%; p=0.363). Adverse events were reported for seven (30.4%) and 14 (60.9%) participants in the benralizumab and placebo groups, respectively., Conclusion: Benralizumab administration over 8 weeks resulted in a significant attenuation of blood, bone marrow and sputum eosinophilia in participants with mild allergic asthma; however, there was no change in the LAR, suggesting that eosinophils alone are not a key component of allergen-induced bronchoconstriction., Competing Interests: Conflict of interest: G.M. Gauvreau reports support for the present manuscript from AstraZeneca, grants from AstraZeneca, payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca, and receipt of equipment, materials, drugs, medical writing, gifts or other services from AstraZeneca. R. Sehmi reports support for the present study from AstraZeneca. R. Leigh reports support for the present study from AstraZeneca, and payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca. D.W. Cockcroft reports support for the present manuscript from AstraZeneca, and grants from SHRF, Biohaven, AllerGen, University of Saskatchewan College of Medicine and CIHR. I. Mayers reports grants from AstraZeneca Canada and Boehringer Ingelheim, consultancy fees from Sanofi Canada and AstraZeneca, payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca, and payment for expert testimony from Alberta Justice. L-P. Boulet reports grants from Amgen, AstraZeneca, GlaxoSmithKline, Merck, Novartis and Sanofi-Regeneron, royalties or licences from UptoDate and Taylor & Francis, consultancy fees from AstraZeneca, Novartis, GlaxoSmithKline, Merck and Sanofi-Regeneron, payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca, GlaxoSmithKline, Novartis, Merck and Sanofi, and leadership role as Past-Chair of the Global Initiative for Asthma (GINA) Board of Directors, Past President of the Global Asthma Organisation (Interasma), Past Member of the Canadian Thoracic Society Respiratory Guidelines Committee and Past Laval University Chair on Knowledge Transfer, Prevention and Education in Respiratory and Cardiovascular Health. T. Ho reports grants from Fisher & Paykel, consultancy fees from Valeo and AstraZeneca, and payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca and GlaxoSmithKline. I. Satia reports grants from Merck, GlaxoSmithKline and Bellus, consultancy fees from Merck, Genentech, Respiplus and GlaxoSmithKline/Bellus, and payment or honoraria for lectures, presentations, manuscript writing or educational events from Merck, GlaxoSmithKline, AstraZeneca and Sanofi. P.D. Mitchell reports grants from Teva, consultancy fees from Pfizer and GlaxoSmithKline, and support for attending meetings from AstraZeneca. I.P. Magee reports payment or honoraria for lectures, presentations, manuscript writing or educational events from GlaxoSmithKline. C. Bergeron reports support for the present study from AstraZeneca, grants from AstraZeneca, Sanofi and Regeneron, consultancy fees from ValeoPharma, Sanofi, AstraZeneca and GlaxoSmithKline, and payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca, GlaxoSmithKline, ValeoPharma, Sanofi and Grifols. M. Bhutani reports grants from CIHR, GlaxoSmithKline, AstraZeneca and Sanofi, consultancy fees from AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Sanofi, Covis and Valeo, and payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca, GlaxoSmithKline, Sanofi and Covis. V. Werkström was an employee of AstraZeneca at the time of the study and reports stock or stock options in AstraZeneca. T. Durżyński was an employee of AstraZeneca at the time of the study and reports stock or stock options in AstraZeneca. K. Shoemaker was an employee of AstraZeneca at the time of the study and reports stock or stock options in AstraZeneca. R.K. Katial was an employee of AstraZeneca at the time of the study and reports personal fees from AstraZeneca. M. Jison was an employee of AstraZeneca at the time of the study and reports stock or stock options in AstraZeneca. C. McCrae was an employee of AstraZeneca at the time of the study and reports stock or stock options in AstraZeneca. P.M. O'Byrne reports support for the present study from AstraZeneca, grants from AstraZeneca, Merck and Biohaven, consultancy fees from AstraZeneca, GlaxoSmithKline, Sage, Teva and Affibody, and payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca, Chiesi, GlaxoSmithKline and Covis. The remaining authors have no potential conflicts of interest to disclose., (Copyright ©The authors 2024.)

Aims: Benralizumab, a humanized, afucosylated monoclonal antibody against the interleukin 5 receptor, α subunit, causes rapid depletion of eosinophils by antibody-dependent cellular cytotoxicity. We investigated the pharmacokinetic and pharmacodynamic effects of benralizumab in patients with chronic rhinosinusitis with nasal polyps (CRSwNP) from the phase III OSTRO trial., Methods: Patients received a placebo or 30 mg of benralizumab by subcutaneous injection every 8 weeks (first three doses every 4 weeks) to week 48; a subset of patients continued in an extended follow-up period to assess treatment durability to week 80. Serum benralizumab concentrations and blood eosinophil and basophil counts were assessed to week 80. Biomarker assessments were performed on nasal polyp tissue biopsies at week 56 and nasal lining fluid at weeks 24 and 56 to examine changes in immune cells and inflammatory mediators., Results: Among 185 patients in this analysis, 93 received benralizumab. Serum benralizumab concentrations reached a steady state by week 24 (median concentration 385.52 ng mL -1 ); blood eosinophils were almost fully depleted and blood basophils were reduced between weeks 16 and 56. Nasal polyp tissue eosinophils decreased with benralizumab from 57.6 cells mm -2 at baseline to 0 cells mm -2 at week 56 (P < .001 vs placebo), and tissue mast cells were numerically reduced. In nasal lining fluid, eosinophil-derived neurotoxin was significantly reduced at weeks 24 and 56 (P < .001) and interleukin-17 at week 56 (P < .05) with benralizumab., Conclusion: Benralizumab treatment led to rapid, sustained, nearly complete depletion of eosinophils from blood and nasal polyp tissue in patients with CRSwNP., (© 2024 AstraZeneca. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Background: Benralizumab is indicated as add-on therapy in patients with uncontrolled, severe eosinophilic asthma; it has not yet been evaluated in a large Asian population with asthma in a clinical trial., Objective: To evaluate the efficacy and safety of benralizumab in patients with severe asthma in Asia., Methods: MIRACLE (NCT03186209) was a randomized, Phase 3 study in China, South Korea, and the Philippines. Patients aged 12-75 years with severe asthma receiving medium-to-high-dose inhaled corticosteroid/long-acting β 2 -agonists, stratified (2:1) by baseline blood eosinophil count (bEOS) (≥300/μL; <300/μL), were randomized (1:1) to benralizumab 30 mg or placebo. Endpoints included annual asthma exacerbation rate (AAER; primary endpoint), change from baseline at Week 48 in pre-bronchodilator (BD) forced expiratory volume in 1 second (pre-BD FEV 1 ) and total asthma symptom score (TASS). Safety was evaluated ≤ Week 56., Results: Of 695 patients randomized, 473 had baseline bEOS ≥300/μL (benralizumab n = 236; placebo n = 237). In this population, benralizumab significantly reduced AAER by 74% (rate ratio 0.26 [95% CI 0.19, 0.36], p < 0.0001) and significantly improved pre-BD FEV 1 (least squares difference [LSD] 0.25 L [95% CI 0.17, 0.34], p < 0.0001) and TASS (LSD -0.25 [-0.45, -0.05], p = 0.0126) versus placebo. In patients with baseline bEOS <300/μL, there were numerical improvements in AAER, pre-BD FEV 1 , and TASS with benralizumab versus placebo. The frequency of adverse events was similar for benralizumab (76%) and placebo (80%) in the overall population., Conclusions: MIRACLE data reinforces the efficacy and safety of benralizumab for severe eosinophilic asthma in an Asian population, consistent with the global Phase 3 results., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Nanshan Zhong reports financial support was provided by AstraZeneca. Kefang Lai reports financial support was provided by AstraZeneca. Dejun Sun reports financial support was provided by AstraZeneca. Ranran Dai reports financial support was provided by AstraZeneca. Ronnie Samoro reports financial support was provided by AstraZeneca. Hae-Sim Park reports financial support was provided by AstraZeneca. Annika Astrand reports a relationship with AstraZeneca that includes: employment and equity or stocks. David Cohen reports a relationship with AstraZeneca that includes: employment and equity or stocks. Maria Jison reports a relationship with AstraZeneca that includes: employment and equity or stocks. Vivian H Shih reports a relationship with AstraZeneca that includes: employment and equity or stocks. Viktoria Werkstrom reports a relationship with AstraZeneca that includes: employment and equity or stocks. Yuhui Yao reports a relationship with AstraZeneca that includes: employment and equity or stocks. Yajuan Zhang reports a relationship with AstraZeneca that includes: employment and equity or stocks. Wenying Zheng reports a relationship with AstraZeneca that includes: employment and equity or stocks. Tanya Jandu and Helen Brereton of inScience Communications, Springer Healthcare Ltd, UK, provided medical writing support, which was funded by AstraZeneca. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Background: Benralizumab is an anti-interleukin-5 receptor α monoclonal antibody approved as an add-on maintenance treatment for patients with uncontrolled severe asthma. Prior Phase 3 studies have evaluated benralizumab in patients aged ≥12 years with severe uncontrolled asthma. The TATE study evaluated the pharmacokinetics (PK), pharmacodynamics (PD), and safety of benralizumab treatment in children., Methods: TATE was an open-label, Phase 3 study of benralizumab in children aged 6-11 years from the United States and Japan (plus participants aged 12-14 years from Japan) with severe eosinophilic asthma. Participants received benralizumab 10/30 mg according to weight (<35/≥35 kg). Primary endpoints included maximum serum concentration (C max ), clearance, half-life (t 1/2 ), and blood eosinophil count. Clearance and t 1/2 were derived from a population PK (popPK) analysis. Safety and tolerability were also assessed., Results: Twenty-eight children aged 6-11 years were included, with an additional two participants from Japan aged 12-14 years also included in the popPK analysis. Mean C max was 1901.2 and 3118.7 ng/mL in the 10 mg/<35 kg and 30 mg/≥35 kg groups, respectively. Clearance was 0.257, and mean t 1/2 was 14.5 days. Near-complete depletion of blood eosinophils was shown across dose/weight groups. Exploratory efficacy analyses found numerical improvements in mean FEV 1 , mean ACQ-IA, patient/clinician global impression of change, and exacerbation rates. Adverse events occurred in 22/28 (78.6%) of participants; none led to discontinuation/death., Conclusion: PK, PD, and safety data support long-term benralizumab in children with severe eosinophilic asthma, and were similar to findings in adolescents and adults., Trial Registration: ClinicalTrials.gov-ID: NCT04305405., (© 2024 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Objectives: The Nasal Polyposis Symptom Diary (NPSD) is a novel and short patient-reported outcome (PRO) tool specifically developed to assess important and relevant symptoms reported by patients with chronic rhinosinusitis with nasal polyposis (CRSwNP). We evaluated the psychometric properties of 4 predefined NPSD-derived scores intended to support symptom-improvement assessments of investigational therapies for inclusion in product labeling., Methods: Five hundred eighteen patients with severe CRSwNP from a Phase III clinical trial (NCT03401229) completed the NPSD, comprising 11 items: 8 symptom-specific, 2 symptom-impact, and 1 optional medication-compliance. The psychometric characteristics of 3 single-item symptom scores (Nasal Blockage Score [NBS], Nasal Congestion Score [NCS], and Difficulty with Sense of Smell Score [DSS]) and a Total Symptom Score (TSS, summary of the 8 symptom-specific items) were evaluated for reliability, validity, and ability to detect change. Within-patient meaningful change thresholds (MCTs) were established using anchor- and distribution-based methods. Comparative PROs included the 22-item Sino-Nasal Outcome Test (SNOT-22) and Patient Global Impression of Severity (PGI-S)., Results: The TSS exhibited strong internal consistency (Cronbach α = .88) and test-retest reliability (intraclass correlation coefficient >.80). Correlation between the TSS and SNOT-22 total score indicated good convergent validity ( r  = .70). All 4 NPSD scores demonstrated known-groups validity (significant differences among subgroups of patients with predetermined disease severity levels based on PGI-S categories) and were sensitive to detect change in patients' clinical status (significant differences among subgroups of patients with reported changes between 2 time-points in PGI-S and Patient Global Impression of Change scores). MCTs for improvement were established at 1.0 point for NBS, NCS, and DSS, and 4.0 points for TSS., Conclusion: These findings support the reliability, validity, and suitability of the 4 NPSD-derived scores for evaluating treatment effect on CRSwNP symptoms and their use in clinical trials with predetermined MCTs for improvement., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: VHS, JK, and VW are employees and shareholders of AstraZeneca. AFS is an employee of Aspen Consulting, LLC, which received funding from AstraZeneca to complete the study. CI and GF are employees of IQVIA, which received funding from AstraZeneca to complete the study. OM was an employee of IQVIA at the time of the study. UJM was an employee and shareholder of AstraZeneca at the time of the study.

Background: Eosinophilic inflammation has been implicated in the pathogenesis, severity, and treatment responsiveness of chronic rhinosinusitis with nasal polyps (CRSwNP)., Objective: We sought to assess the efficacy and safety of benralizumab-mediated eosinophil depletion for treating CRSwNP., Methods: The phase 3 OSTRO study enrolled patients with severe CRSwNP who were symptomatic despite treatment with intranasal corticosteroids and who had a history of systemic corticosteroid (SCS) use and/or surgery for nasal polyps (NP). Patients were randomized 1:1 to treatment with benralizumab 30 mg or placebo every 4 weeks for the first 3 doses and every 8 weeks thereafter. Coprimary end points were change from baseline to week 40 in NP score (NPS) and patient-reported mean nasal blockage score reported once every 2 weeks., Results: The study population comprised 413 randomized patients (207 in the benralizumab group and 206 in the placebo group). Benralizumab significantly improved NPS and nasal blockage score compared to placebo at week 40 (P ≤ .005). Improvements in Sinonasal Outcome Test 22 score at week 40, time to first NP surgery and/or SCS use for NP, and time to first NP surgery were not statistically significant between treatment groups. Nominal significance was obtained for improvement in difficulty in sense of smell score at week 40 (P = .003). Subgroup analyses suggested influences of comorbid asthma, number of NP surgeries, sex, body mass index, and baseline blood eosinophil count on treatment effects. Benralizumab was safe and well tolerated., Conclusion: Benralizumab, when added to standard-of-care therapy, reduced NPS, decreased nasal blockage, and reduced difficulty with sense of smell compared to placebo in patients with CRSwNP., Trial Registration: ClinicalTrials.gov NCT03401229., (Copyright © 2021 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Purpose: In the Phase III SIROCCO trial (NCT01928771), benralizumab significantly reduced asthma exacerbations and improved lung function and symptoms for patients with severe, uncontrolled eosinophilic asthma. The aim of this subgroup analysis was to evaluate efficacy and safety of benralizumab for Korean patients in SIROCCO., Methods: SIROCCO was a randomized, double-blind, parallel-group, placebo-controlled trial of 1,204 patients aged 12-75 years with severe asthma uncontrolled by high-dosage inhaled corticosteroids/long-acting β₂-agonists (ICS/LABA). Patients received benralizumab 30 mg every 4 weeks (Q4W) or every 8 weeks (Q8W; first 3 doses Q4W) or placebo Q4W for 48 weeks. The primary analysis population comprised patients with blood eosinophil counts ≥ 300 cells/μL. This subgroup analysis evaluated Korean patients from this group., Results: Of 122 Korean patients randomized, 86 had blood eosinophil counts ≥ 300 cells/μL. Benralizumab reduced the annual asthma exacerbation rate by 70% (Q4W: rate estimate 0.79, rate ratio 0.30 [95% confidence interval {CI}, 0.13-0.65], nominal P = 0.003; n = 28) and 85% (Q8W: rate estimate 0.40, rate ratio 0.15 [95% CI, 0.06-0.36], nominal P < 0.001; n = 30) vs. placebo (rate estimate 2.67, n = 28). Prebronchodilator forced expiratory volume in 1 second was increased with benralizumab treatment by 0.270 L (Q4W: 95% CI, 0.039-0.500, nominal P = 0.023; n = 28) and 0.362 L (Q8W: 95% CI, 0.143-0.582, nominal P = 0.002; n = 30) vs. placebo (n = 27). Total asthma symptom score was similar for patients receiving either benralizumab Q4W (-0.27 [95% CI, -0.83 to 0.30], nominal P = 0.356; n = 27) or benralizumab Q8W (0.10 [95% CI, -0.44 to 0.65], nominal P = 0.708; n = 30) vs. placebo (n = 28). Drug-related adverse events were experienced by 2%, 8%, and 5% of patients in the placebo, benralizumab Q4W, and benralizumab Q8W arms., Conclusions: Benralizumab reduced annual asthma exacerbation rates, increased lung function, and was well-tolerated by Korean patients with severe, uncontrolled eosinophilic asthma., Competing Interests: There are no financial or other issues that might lead to conflicts of interest., (Copyright © 2019 The Korean Academy of Asthma, Allergy and Clinical Immunology · The Korean Academy of Pediatric Allergy and Respiratory Disease.)

Background: Several inhaled drugs are dependent on organic cation transporters to cross cell membranes. To further evaluate their potential to impact on inhaled drug disposition, the localization of MATE1, P-gp, OCTN1 and OCTN2 were investigated in human lung., Methods: Transporter proteins were analysed by immunohistochemistry in lung tissue from healthy subjects and COPD patients. Transporter mRNA was analysed by qPCR in lung tissue and in bronchoalveolar lavage (BAL) cells from smokers and non-smokers., Results: We demonstrate for the first time MATE1 protein expression in the lung with localization to the apical side of bronchial and bronchiolar epithelial cells. Interestingly, MATE1 was strongly expressed in alveolar macrophages as demonstrated both in lung tissue and in BAL cells, and in inflammatory cells including CD3 positive T cells. P-gp, OCTN1 and OCTN2 were also expressed in the alveolar epithelial cells and in inflammatory cells including alveolar macrophages. In BAL cells from smokers, MATE1 and P-gp mRNA expression was significantly lower compared to cells from non-smokers whereas no difference was observed between COPD patients and healthy subjects. THP-1 cells were evaluated as a model for alveolar macrophages but did not reflect the transporter expression observed in BAL cells., Conclusions: We conclude that MATE1, P-gp, OCTN1 and OCTN2 are expressed in pulmonary lung epithelium, in alveolar macrophages and in other inflammatory cells. This is important to consider in the development of drugs treating pulmonary disease as the transporters may impact drug disposition in the lung and consequently affect pharmacological efficacy and toxicity.

AZD5423 is a selective glucocorticosteroid receptor modulator developed for the inhaled use in asthma and COPD. This study reports the initial, first-in-man, single and repeat dose-escalating studies in healthy male individuals, including one cohort of male Japanese individuals. Inhaled, nebulized AZD5423 was safe and well tolerated up to and including the highest doses tested for up to 2 weeks of once-daily treatment. Plasma exposure suggested dose-proportional pharmacokinetics and dose-related effects on 24-hr plasma and urine cortisol. There were no or marginal effects on other biomarkers tested (osteocalcin, TRAP5b, DHEA-S and 4β-OH-cholesterol). No clinically relevant differences in safety or pharmacokinetics could be distinguished between the two study populations, although hypothalamus-pituitary-adrenal (HPA) effects appeared to be marginally greater in the Japanese- versus the Caucasian-dominant study population. AZD5423, inhaled via nebulization, can be used in healthy individuals at doses of at least 300 μg for 2 weeks. The effects on the HPA axis reported herein, together with efficacy data reported elsewhere, indicate that benefit-risk ratio may be improved relative to conventional inhaled steroids., (© 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).)

Background: Eosinophilia is associated with worsening asthma severity and decreased lung function, with increased exacerbation frequency. We assessed the safety and efficacy of benralizumab, a monoclonal antibody against interleukin-5 receptor α that depletes eosinophils by antibody-dependent cell-mediated cytotoxicity, for patients with severe, uncontrolled asthma with eosinophilia., Methods: We did a randomised, double-blind, parallel-group, placebo-controlled phase 3 study at 374 sites in 17 countries. We recruited patients (aged 12-75 years) with a physician-based diagnosis of asthma for at least 1 year and at least two exacerbations while on high-dosage inhaled corticosteroids and long-acting β 2 -agonists (ICS plus LABA) in the previous year. Patients were randomly assigned (1:1:1) by an interactive web-based voice response system to benralizumab 30 mg either every 4 weeks (Q4W) or every 8 weeks (Q8W; first three doses every 4 weeks) or placebo Q4W for 48 weeks as add on to their standard treatment. Patients were stratified 2:1 according to blood eosinophil counts of at least 300 cells per μL and less than 300 cells per μL. All patients and investigators involved in patient treatment or clinical assessment were masked to treatment allocation. The primary endpoint was annual exacerbation rate ratio versus placebo, and key secondary endpoints were prebronchodilator forced expiratory volume in 1 s (FEV 1 ) and total asthma symptom score at week 48, for patients with blood eosinophil counts of at least 300 cells per μL. Efficacy analyses were by intention to treat (based on the full analysis set); safety analyses included patients according to study drug received. This study is registered with ClinicalTrials.gov, number NCT01928771., Findings: Between Sept 19, 2013, and March 16, 2015, 2681 patients were enrolled, 1205 of whom met the study criteria and were randomly assigned: 407 to placebo, 400 to benralizumab 30 mg Q4W, and 398 to benralizumab 30 mg Q8W. 267 patients in the placebo group, 275 in the benralizumab 30 mg Q4W group, and 267 in the benralizumab 30 mg Q8W group had blood eosinophil counts at least 300 cells per μL and were included in the primary analysis population. Compared with placebo, benralizumab reduced the annual asthma exacerbation rate over 48 weeks when given Q4W (rate ratio 0·55, 95% CI 0·42-0·71; p<0·0001) or Q8W (0·49, 0·37-0·64; p<0·0001). Both benralizumab dosing regimens significantly improved prebronchodilator FEV 1 in patients at week 48 compared with placebo (least-squares mean change from baseline: Q4W group 0·106 L, 95% CI 0·016-0·196; Q8W group 0·159 L, 0·068-0·249). Compared with placebo, asthma symptoms were improved by the Q8W regimen (least-squares mean difference -0·25, 95% CI -0·45 to -0·06), but not the Q4W regimen (-0·08, -0·27 to 0·12). The most common adverse events were worsening asthma (105 [13%] of 797 benralizumab-treated patients vs 78 [19%] of 407 placebo-treated patients) and nasopharyngitis (93 [12%] vs 47 [12%])., Interpretation: These results confirm the efficacy and safety of benralizumab for patients with severe asthma and elevated eosinophils, which are uncontrolled by high-dosage ICS plus LABA, and provide support for benralizumab to be an additional option to treat this disease in this patient population., Funding: AstraZeneca and Kyowa Hakko Kirin., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Benralizumab is a humanised, afucosylated, anti-interleukin-5 receptor α monoclonal antibody that induces direct, rapid, and nearly complete depletion of eosinophils. We aimed to assess the efficacy and safety of benralizumab as add-on therapy for patients with severe, uncontrolled asthma and elevated blood eosinophil counts., Methods: In this randomised, double-blind, parallel-group, placebo-controlled, phase 3 study (CALIMA) undertaken at 303 sites in 11 countries, we enrolled patients aged 12-75 years with severe asthma uncontrolled by medium-dosage to high-dosage inhaled corticosteroids plus long-acting β₂-agonists (ICS plus LABA) and a history of two or more exacerbations in the previous year. Patients were randomly assigned (1:1:1) to receive 56 weeks of benralizumab 30 mg every 4 weeks (Q4W), benralizumab 30 mg every 8 weeks (Q8W; first three doses 4 weeks apart), or placebo (all subcutaneous injection). Patients were stratified (2:1) by baseline blood eosinophil counts 300 cells per μL or greater and less than 300 cells per μL, respectively. Patients and study centre staff were masked to treatment allocation. The primary endpoint was annual exacerbation rate ratio versus placebo for patients receiving high-dosage ICS plus LABA with baseline blood eosinophils 300 cells per μL or greater (intention-to-treat analysis). Key secondary endpoints were pre-bronchodilator forced expiratory volume in 1 s (FEV 1 ) and total asthma symptom score. This study is registered with ClinicalTrials.gov, number NCT01914757., Findings: Between Aug 21, 2013, and March 16, 2015, 2505 patients were enrolled, of whom 1306 patients were randomised; 425 patients were randomly assigned to and received benralizumab 30 mg Q4W, 441 to benralizumab 30 mg Q8W, and 440 to placebo. 728 patients were included in the primary analysis population. Benralizumab resulted in significantly lower annual exacerbation rates with the Q4W regimen (rate 0·60 [95% CI 0·48-0·74], rate ratio 0·64 [95% CI 0·49-0·85], p=0·0018, n=241) and Q8W regimen (rate 0·66 [95% CI 0·54-0·82], rate ratio 0·72 [95% CI 0·54-0·95], p=0·0188, n=239) compared with placebo (rate 0·93 [95% CI 0·77-1·12], n=248). Benralizumab also significantly improved pre-bronchodilator FEV 1 (Q4W and Q8W) and total asthma symptom score (Q8W only) in these patients. The most common adverse events were nasopharyngitis (90 [21%] in the Q4W group, 79 [18%] in the Q8W group, and 92 [21%] in the placebo group) and worsening asthma (61 [14%] in the Q4W group, 47 [11%] in the Q8W group, and 68 [15%] in the group)., Interpretation: Benralizumab significantly reduced annual exacerbation rates and was generally well tolerated for patients with severe, uncontrolled asthma with blood eosinophils 300 cells per μL or greater. Our data further refine the patient population likely to receive the greatest benefit from benralizumab treatment., Funding: AstraZeneca and Kyowa Hakko Kirin., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

This study describes for the first time the expression levels of genes encoding membrane transporters and drug-metabolizing enzymes in the lungs of ex-smoking patients with chronic obstructive pulmonary disease (COPD). Membrane transporters and drug-metabolizing enzymes are key determinants of drug uptake, metabolism, and elimination for systemically administered as well as inhaled drugs, with consequent influence on clinical efficacy and patient safety. In this study, while no difference in gene expression was found between healthy and COPD subjects, we identified a significant regional difference in mRNA expression of both membrane transporters and drug-metabolizing enzymes between central and peripheral tissue in both healthy and COPD subjects. The majority of the differentially expressed genes were higher expressed in the central airways such as the transporters SLC2A1 (GLUT1), SLC28A3 (CNT3), and SLC22A4 (OCTN1) and the drug-metabolizing enzymes GSTZ1, GSTO2, and CYP2F1. Together, this increased knowledge of local pharmacokinetics in diseased and normal lung may improve modeling of clinical outcomes of new chemical entities intended for inhalation therapy delivered to COPD patients. In addition, based on the similarities between COPD and healthy subjects regarding gene expression of membrane transporters and drug-metabolizing enzymes, our results suggest that clinical pharmacological studies in healthy volunteers could be a valid model of COPD patients regarding drug disposition of inhaled drugs in terms of drug metabolism and drug transporters.

Aim: To describe spontaneously reported cases of erectile dysfunction (ED) in association with angiotensin II type I blockers (ARB) and other antihypertensive drugs., Subjects and Methods: All spontaneously reported cases of ED submitted to the Swedish Medical Products Agency (MPA) between 1990 and 2006, where at least one antihypertensive drug was the suspected agent, were scrutinized. Patient demographics, drug treatment and adverse reactions were recorded. Using the Bayesian Confidence Propagation Neural Network (BCPNN) method, the information component (IC) was calculated., Results: Among a total of 225 reports of ED, 59 involved antihypertensive drugs including ARB (9 cases) as suspected agents. A positive IC value was found indicating that ED was reported more often in association with antihypertensive drugs classes, except for angiotensin-converting enzyme inhibitors, compared with all other drugs in the database. Positive dechallenge was reported in 43 cases (72%)., Discussion: All classes of major antihypertensive drugs including ARB were implicated as suspected agents in cases of ED. Few risk factors were identified. The relatively high reporting of ED in association with ARB is in contrast with previous studies, suggesting that ARB have neither a positive nor any effect on ED. This discrepancy suggests that further studies are warrnted on this potential adverse reaction to ARB.

Objective: To study the effects of the phosphodiesterase-5 inhibitor, vardenafil, on contraction and cyclic nucleotide levels in isolated detrusor preparations with and without mucosa, from control rats and rats with partial urethral obstruction (PUO) and intact mucosa., Materials and Methods: Female Sprague-Dawley rats were divided into groups subjected to PUO for 14 days (six), and sham-operated control rats (12). Detrusor preparations were mounted in organ baths and effects of increasing concentrations of vardenafil (1 nm to 100 microm) assessed on carbachol-activated (1 microm) preparations, and on contractions induced by transmural activation of nerves (electrical field stimulation, EFS). Levels of cGMP and cAMP were determined using radioimmunoassays., Results: Vardenafil caused concentration-dependent relaxations of carbachol-contracted detrusor, the mean (sd) of which at 100 microm was 91 (4)% in control and 100% in PUO rats. The -log 50% inhibitory concentration (IC(50)) was 4.41 (0.08) and 4.73 (0.05) (P < 0.01), respectively. Removing the mucosa increased the relaxant effect of vardenafil at 1-10 microm (P < 0.05) although -log IC(50) values were unaffected compared to the control. The cGMP levels ( pmol/mg protein) in control preparations increased from 2.5 (0.6) to 5.0 (0.8), and from 1.4 (0.2) to 7.2 (1.3) in obstructed bladders. In mucosa-denuded preparations the cGMP content increased from 0.6 (0.1) to 1.6 (0.4) in response to vardenafil. In control rats, the levels of cAMP increased from 12.8 (2.5) to 18.9 (0.9) (P < 0.05) after vardenafil. In mucosa-denuded preparations the cAMP levels after vardenafil increased from 16.5 (2.11) to 37.8 (3.4) (P < 0.01). In PUO bladders, the tissue content of cAMP increased from 12.6 (2.4) to 20.6 (3.4) (P < 0.01). Vardenafil concentration-dependently inhibited nerve-induced contractions in all groups studied. At 100 microm 19 (3)% of the control contraction remained, vs 8 (1)% for preparations from obstructed rats, and 11 (4)% in mucosa-denuded preparations., Conclusion: In normal rats, vardenafil relaxed carbachol- and inhibited EFS-induced contractions of detrusor preparations with and without urothelium, and in PUO rats with urothelium. Relaxations were accompanied by increases in both cAMP and cGMP content. It is proposed that vardenafil-induced relaxation of rat detrusor, also in obstructed and mucosa-denuded preparations, is mediated via cAMP.

What Is Already Known About This Subject: The occurrence of idiosyncratic drug hepatotoxicity is a major problem in all phases of clinical drug development and the leading cause of postmarketing warnings and withdrawals. Physical exercise can result in transient elevations of liver function tests. There is no consensus in the literature on which forms of exercise may cause changes in liver function tests and to what extent., What This Study Adds: Weightlifting results in profound increases in liver function tests in healthy men used to moderate physical activity, not including weightlifting. Liver function tests are significantly increased for at least 7 days after weightlifting. It is important to impose relevant restrictions on heavy muscular exercise prior to and during clinical studies., Aim: To investigate the effect of intensive muscular exercise (weightlifting) on clinical chemistry parameters reflecting liver function in healthy men., Methods: Fifteen healthy men, used to moderate physical activity not including weightlifting, performed an 1 h long weightlifting programme. Blood was sampled for clinical chemistry parameters [aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LD), gamma-glutamyl transferase (gamma GT), alkaline phosphatase (ALP), bilirubin, creatine kinase (CK) and myoglobin] at repeated intervals during 7 days postexercise and at a follow-up examination 10-12 days postexercise., Results: Five out of eight studied clinical chemistry parameters (AST, ALT, LD, CK and myoglobin) increased significantly after exercise (P < 0.01) and remained increased for at least 7 days postexercise. Bilirubin, gamma GT and ALP remained within the normal range., Conclusion: The liver function parameters, AST and ALT, were significantly increased for at least 7 days after the exercise. In addition, LD and, in particular, CK and myoglobin showed highly elevated levels. These findings highlight the importance of imposing restrictions on weightlifting prior to and during clinical studies. Intensive muscular exercise, e.g. weightlifting, should also be considered as a cause of asymptomatic elevations of liver function tests in daily clinical practice.

Objective: To characterize the distribution of phosphodiesterase 5 (PDE-5), cGMP and cGMP-dependent protein kinase I (PKG1), and to evaluate the effect of pharmacological inhibition of PDE-5 in isolated preparations of pig and human urethra, as the nitric oxide (NO)/cGMP pathway generates the main inhibitory signals to reduce resistance in the bladder outlet and urethra during emptying of the bladder., Materials and Methods: After obtaining ethics committee approval, urethral specimens were obtained from three female patients during cystectomy, and from young female pigs. The specimens were prepared for immunohistochemical investigations and for functional studies in organ baths. Effects of sildenafil, vardenafil and tadalafil (1 nm to 30 microm) were studied in l-noradrenaline (1 microm)-activated or spontaneously contracted preparations, and on relaxations induced by electrical-field stimulation (EFS). Levels of cGMP were determined by radioimmunoassay., Results: After stimulation with the NO donor, DETA NONO-ate (1 mm), there was greater cGMP-immunoreactivity (IR) in urethral and vascular smooth muscles. There was a wide distribution of cGMP- and vimentin-positive interstitial cells between pig urethral smooth muscle bundles. There was also cGMP-IR within NO-synthase-IR endothelium. There was PDE-5 IR within the urethral and vascular smooth muscle cells, but also in vascular endothelial cells that expressed cGMP-IR. In pig and human sections, there was strong PKG1-IR in alpha-actin-IR urethral smooth muscle cells that also contained IR for cGMP. Sildenafil, vardenafil and tadalafil caused mean (sem) concentration-dependent relaxations of the pig urethra which, at 30 microm, were 80 (3)% (11 samples), 81 (5)% (12 samples) and 64 (4)% (10 samples) of the spontaneous tone. The relaxation of L-noradrenaline-contracted female human urethra was 100% in response to 10 microm sildenafil, and 85 (15)% and 47 (13)% for 30 microm of vardenafil and tadalafil, respectively (three samples). Vardenafil or sildenafil (30 microm) doubled cGMP levels in pig specimens. There were no effects on cGMP levels with tadalafil. EFS (1-32 Hz) caused l-NG-nitroarginine-sensitive relaxations of pig urethral muscle that were increased in amplitude and duration by PDE-5 inhibition. At 0.1 microm, sildenafil, vardenafil or tadalafil significantly prolonged the mean (sem) duration of the relaxation at 4 Hz by 55 (19)%, 45 (14)% and 51 (12)%, respectively., Conclusions: PDE-5-, cGMP- and PKG1-IR is widely distributed in human and pig urethral tissues. Nerve-induced relaxations of urethral preparations were enhanced at low concentrations of sildenafil, vardenafil and tadalafil, whereas there were direct smooth muscle-relaxant actions of the PDE-5 inhibitors at high concentrations. Inhibition of PDE-5 might be an interesting option to facilitate cGMP-mediated relaxation of the outflow region.

Objectives: To investigate relaxation mechanisms for ATP and adenosine in the pig urethra, together with the possible role of ATP in nerve-evoked urethral relaxations, as ATP is thought to cause bladder smooth muscle contraction via P2X receptors, whereas relaxation is mediated via G-protein coupled P2Y receptors, and ATP may also induce relaxation via breakdown to adenosine., Materials and Methods: Circular muscle strips from the female pig urethra were mounted in tissue baths to record force; the effects of increasing concentrations of 1-300 microM ATP, the P2-receptor agonist 2-methylthioATP (2-MeSATP), adenosine, the stable adenosine-analogue, 5'(N-ethylcarboxamido) adenosine (NECA), ADP, uridine-triphosphate (UTP) and alpha,beta-methylene-ATP were assessed on the spontaneously developed tone. Responses to ATP were further assessed in the presence of G-protein activator guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS; 1-10 microM), the G-protein inhibitor guanosine 5'-O-(2-thio-diphosphate) (GDPbetaS; 10-100 microM), suramin (1-100 microM), the ecto-ATPase inhibitor 6-N,N-diethyl-beta-gamma-dibromomethylene-D-adenosine-5-triphosphate (ARL 67156, 10-100 microM), and the suggested P2Y receptor antagonist, reactive blue-2 (1-100 microM). The effect of the adenosine (P1) receptor antagonist 8-(p-sulphophenyl)theophylline (8-SPT, 1-100 microM) on responses to adenosine, and the effects of the adenosine reuptake inhibitor S(p-nitrobenzyl)-6-thioinosine (NBTI, 1-100 microM) on responses to adenosine and ATP were also assessed. Responses to electrical field stimulation (EFS, 12 and 30 Hz) in the presence of phentolamine (1 microM), scopolamine (1 microM) and N omega-nitro-L-arginine (0.3 mM) were studied before and after treatment with GTPgammaS, GDPbetaS, suramin, reactive blue-2 and ARL 67156., Results: Strips were relaxed in a concentration-dependent manner by exogenously administered ATP and 2-meSATP, the relaxations being slowly developing and long-lasting. The relaxant effect evoked by both agonists at 300 microM amounted to about half of the spontaneously developed tone. The relaxation evoked by ATP was not significantly affected by GTPgammaS, GDPbetaS, suramin, ARL 67156 or reactive blue-2. Adenosine induced a concentration-dependent relaxation of the smooth muscle tone, reaching a maximum of approximately 70% at 300 microM, whereas 300 microM NECA only relaxed the preparations by approximately 35%. The adenosine-induced relaxation was not affected by treatment with 8-SPT. However, NBTI (1 microM) significantly reduced the relaxation evoked by 300 microM adenosine. ADP relaxed the smooth muscle tone by approximately 40% (300 microM). There was no response to UTP, and the effect of alpha,beta-methylene-ATP was negligible (5% relaxation at 100 microM). EFS caused slowly developing and long-lasting relaxations that were unaffected by GTPgammaS, GDPbetaS, suramin, reactive blue-2 and ARL 67156., Conclusions: These results suggest that exogenous ATP and adenosine relax the smooth muscle of the pig urethra in a manner similar to that evoked by electrical stimulation of nerves, although there was no evidence for involvement of a definable P2Y receptor subtype in these relaxations.

The inhibitory innervation of guinea-pig urethral smooth muscle was investigated histochemically and functionally. The distribution of immunoreactivities to haem oxygenases (HO), neuronal NO synthase (nNOS), and vasoactive intestinal polypeptide (VIP) was studied, and the functional effects of the corresponding putative transmitters, CO, NO, and VIP, were assessed. HO-2 immunoreactivity was found in all nerve cell bodies of intramural ganglia, localized between smooth muscle bundles in the detrusor, bladder base and proximal urethra. About 70% of the ganglionic cell bodies were also NOS-immunoreactive (IR), whereas a minor part was VIP-IR. Some ganglion cells exhibiting tyrosine hydroxylase (TH) activity were demonstrated. Rich numbers of NOS-IR varicose nerve terminals could be found innervating the smooth muscle of the urethra, whereas VIP-IR terminals were less numerous. A rich number of TH-IR terminals were observed. The bladder showed a similar distribution of nerves, although only a few number of TH-IR nerves could be found. In bladder preparations exposed to sodium nitroprusside, cGMP-IR cells could be seen, forming an interconnecting network with long spindle-shaped processes. The cGMP-IR cells were especially abundant in the outer smooth muscle layers of the bladder, but less numerous in the urethra. In urethral strip preparations, electrical field stimulation evoked long-lasting frequency-dependent relaxations. The relaxations were not inhibited by the NO-synthesis inhibitor, L-NOARG, or enhanced by the NO-precursor, L-arginine. The haem precursor, 5-aminolevulinic acid (5-ALA), or the inhibitor of guanylate cyclase, ODQ, did not affect the urethral relaxations. Exogenously applied NO, SIN-1, and VIP relaxed the preparations by approximately 50%, whereas the relaxation evoked by exogenous CO was minor. These results suggest that CO probably is not involved in non-adrenergic, non-cholinergic inhibitory control of the guinea-pig urethra, where a non-NO/cGMP mediated relaxation seems to be predominant.

Neuronal regulation of smooth muscle tone in the female pig urethra has mainly been studied in vitro using electrical field stimulation (EFS) of nerves. Excitatory control is considered to be exerted by released noradrenaline, whereas inhibitory control is non-adrenergic non-cholinergic (NANC), and mediated by nitric oxide (NO), and an as yet unidentified agent. We investigated the functional and morphological effects of alpha-latrotoxin (alphaLTX), a spider neurotoxin believed to cause massive release of vesicle-stored neurotransmitters, on spontaneously developed urethral smooth muscle tone. The effects were compared to those of EFS and high potassium. In the presence of the NO-synthesis inhibitor N(omega)-nitro-L-arginine (L-NOARG: 0.3 mM) both alphaLTX and EFS evoked contractions. After treatment with scopolamine and phentolamine, no contraction was observed, and under these conditions alphaLTX and EFS induced relaxation. At low frequencies (<12 Hz), the EFS-induced relaxations were rapid, whereas at higher frequencies (>12 Hz), they were biphasic, consisting of a rapid first phase followed by a more long-lasting second phase. L-NOARG abolished the relaxations at low frequencies, as well as the first phase of the biphasic relaxation. The second phase was not affected by treatment with L-NOARG, but 0.1 microM omega-conotoxin GVIA, blocker of N-type voltage-operated calcium- channels (VOCCs), markedly reduced or abolished the response. In the presence of L-NOARG or omega-conotoxin GVIA, the alphaLTX-induced relaxation was significantly decreased, and the combination of L-NOARG and omega-conotoxin GVIA further reduced or abolished the relaxation. In preparations-treated with tetrodotoxin or scorpion venom, believed to inactivate nerves by acting on sodium channels, alphaLTX and EFS had no effects. alphaLTX-induced relaxation was not associated with changes in cyclic GMP or cyclic AMP content. High (80 mM) potassium solution induced a triphasic response of the preparation. A transient relaxation was followed by a restoration of tone, and then by a persistent relaxation. The persistent relaxation was slightly reduced by scorpion venom or L-NOARG, but reduced by 50% by a combination of L-NOARG and omega-conotoxin GVIA. Ultrastructural analysis of the urethral circular smooth muscle layer revealed a moderate amount of nerve profiles supplying the smooth muscle. In control preparations, the nerve profiles contained both small synaptic vesicles and large dense core vesicles. alphaLTX caused a major loss of both types of vesicle. The present data suggest that alphaLTX has the ability to release not only adrenergic and cholinergic transmitters, but also NANC mediators of relaxation, including NO, from nerve terminals in the urethra.

1. To investigate further the release, localization and identity of a non-nitrergic mediator of smooth muscle relaxation in the female pig urethra, we studied the effects of drugs acting at alpha 2-adrenoceptors or K+ channels, the effects of capsaicin and chemical sympathectomy, and the actions of several transmitter candidates. 2. Electrical field stimulation (EFS; frequencies above 12 Hz) of spontaneously contracted smooth muscle strips from the female pig urethra evoked long-lasting, frequency-dependent relaxations in the presence of prazosin, scopolamine, and NG-nitro-L-arginine. Treatment with the selective alpha 2-adrenoceptor agonist UK-14 304 markedly reduced the relaxations evoked by EFS at all frequencies tested (16-30 Hz). The inhibitory effect of UK-14 304 was completely antagonized by the alpha 2-adrenoceptor antagonist rauwolscine. The muscarinic M1 receptor antagonist, pirenzepine, or exogenously administered carbachol, did not have any effects on the electrically evoked relaxations. 3. Inhibition of high conductance Ca2+ activated K+ channels by iberiotoxin or charybdotoxin significantly enhanced the relaxations evoked by EFS at all frequencies. However, inhibition of voltage-sensitive K+ channels with 4-aminopyridine or dendrotoxin-1, treatment with the ATP-sensitive K+ channel blocker, glibenclamide, or treatment with the high and low conductance Ca2+ activated K+ channel blockers, tetraethylammonium chloride and apamin, had no effect on the relaxations evoked by EFS. 4. Electrically evoked relaxations were not affected by adrenergic denervation with 6-hydroxydopamine (6-OHDA) at any frequency. However, treatment with 6-OHDA abolished prazosin-sensitive electrically induced contractions, and a long-lasting relaxation was revealed. Treatment with capsaicin, believed to damage selectively a subpopulation of primary afferent fibres, did not affect basal tone or relaxations evoked by EFS. 5. Exogenously applied vasoactive intestinal polypeptide (VIP), pituitary adenylate cyclase-activating peptide (PACAP)-27, PACAP-38, adenosine, ATP and 5-hydroxy-tryptamine caused relaxations of the urethral preparations, whereas prostaglandin E2 and calcitonin gene-related peptide had no effects. VIP 10-28, alpha, beta-methylene-ATP, reactive blue-2, suramin or indomethacin did not reduce the electrically-evoked relaxations at any frequency. However, the relaxations were slightly reduced by trypsin or alpha-chymotrypsin. 6. The present results suggest that the release of the unknown mediator in the female pig urethra can be modulated via alpha 2-adrenoceptors and high conductance Ca2+ activated K+ channels. Furthermore, the mediator does not appear to be localized to or released from adrenergic or capsaicin-sensitive sensory nerve-endings. The identity of the transmitter remains to be established.

1. Non-adrenergic, non-cholinergic (NANC) relaxations induced by electrical field stimulation (EFS) were studied in pig isolated urethra. The mechanism for relaxation was characterized by measurement of cyclic nucleotides and by study of involvement of different subsets of voltage-operated calcium channels (VOCCs). 2. EFS evoked frequency-dependent and tetrodotoxin-sensitive relaxations in the presence of propranolol (1 microM), phentolamine (1 microM) and scopolamine (1 microM). At low frequencies (< 12 Hz), relaxations were rapid, whereas at high (> 12 Hz) frequencies distinct biphasic relaxations were evoked. The latter consisted of a rapidly developing first phase followed by a more long-lasting second phase. 3. Treatment with the NO-synthesis inhibitor NG-nitro-L-arginine (L-NOARG; 0.3 mM) inhibited relaxations at low frequencies of stimulation. At high frequencies (> 12 Hz) only the first relaxation phase was affected. 4. Measurement of cyclic nucleotides in preparations subjected to continuous nerve-stimulation, revealed an increase in guanosine 3':5'-cyclic monophosphate (cyclic GMP) levels from 1.3 +/- 0.3 to 3.0 +/- 0.4 pmol mg-1 protein (P < 0.01). In the presence of L-NOARG, there was a significant decrease in cyclic GMP content to control. However, there was no increase in cyclic GMP content in response to EFS. Levels of cyclic AMP remained unchanged following EFS. 5. Treatment with the N-type VOCC-inhibitor, omega-conotoxin GVIA (0.1 microM) reduced NO-dependent relaxations, the effect being most pronounced at low frequencies (1-4 Hz) of stimulation. The NO independent second phase of the relaxation, studied in the presence of L-NOARG (0.3 mM) at 16-30 Hz, was however markedly reduced or abolished by omega-conotoxin GVIA. omega-Conotoxin MVIIC (1 microM)or omega-agatoxin IVA (30 nM) had no effect on electrically evoked relaxations.6. These results suggest that NANC-nerve derived urethral relaxation in the pig consists of two apparently independent components. One is mediated by NO and associated with an increase in cyclic GMP content. The other mediator is unknown and produces relaxations not associated with changes in levels of cyclic nucleotides. The release of this mediator seems to involve the N-type VOCC, since the relaxation was markedly reduced or abolished by omega-conotoxin GVIA.