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Novel digital endpoints gathered via wearables, small devices, or algorithms hold great promise for clinical trials. However, implementation has been slow because of a lack of guidelines regarding the validation process of these new measurements. In this paper, we propose a pragmatic approach toward selection and fit-for-purpose validation of digital endpoints. Measurements should be value-based, meaning the measurements should directly measure or be associated with meaningful outcomes for patients. Devices should be assessed regarding technological validity. Most importantly, a rigorous clinical validation process should appraise the tolerability, difference between patients and controls, repeatability, detection of clinical events, and correlation with traditional endpoints. When technically and clinically fit-for-purpose, case building in interventional clinical trials starts to generate evidence regarding the response to new or existing health-care interventions. This process may lead to the digital endpoint replacing traditional endpoints, such as clinical rating scales or questionnaires in clinical trials. We recommend initiating more data-sharing collaborations to prevent unnecessary duplication of research and integration of value-based measurements in clinical care to enhance acceptance by health-care professionals. Finally, we invite researchers and regulators to adopt this approach to ensure a timely implementation of digital measurements and value-based thinking in clinical trial design and health care. SIGNIFICANCE STATEMENT: Novel digital endpoints are often cited as promising for the clinical trial of the future. However, clear validation guidelines are lacking in the literature. This paper contains pragmatic criteria for the selection, technical validation, and clinical validation of novel digital endpoints and provides recommendations for future work and collaboration.
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Ensaios Clínicos como Assunto/métodos , Biomarcadores/análise , Biomarcadores/metabolismo , Determinação de Ponto Final/métodos , Humanos , Reprodutibilidade dos TestesRESUMO
PURPOSE: Fractal analysis can be used to quantitatively analyze the retinal microvasculature and might be a suitable method to quantify retinal capillary changes in sickle cell disease (SCD) patients. Retinal oximetry measurements might function as a proxy for the pathophysiology of cerebrovascular diseases. Moreover, hypoxia has an important role in the pathophysiology of diabetic and other retinopathies. However, little is known about the oximetry around the macula in SCD patients. With this study, we explored the feasibility to perform these quantified measurements in SCD patients. METHODS: Retinal microvascular and oximetry measurements were performed in eight SCD patients and eight healthy matched controls. Oximetry pictures and non-invasive capillary perfusion maps (nCPM) were obtained by the retinal function imager. Measurements were conducted twice on two different study days. Measured variables included monofractal dimension (Dbox), relative saturation, deoxygenated hemoglobin (deoxyHb), and oxygenated hemoglobin (oxyHb) concentration. RESULTS: No statistically significant differences in vessel density were found in the different annular zones (large vessels, p = 0.66; small vessels, p = 0.66) and anatomical quadrants (large vessels, p = 0.74; small vessels, p = 0.72). Furthermore, no significant between-group differences were found in the other different anatomical quadrants and annular zones around the fovea for relative saturation levels and deoxygenated Hb. However, the oxyHb levels were significantly lower in SCD patients, compared with those in matched controls in the temporal quadrants (p = 0.04; p = 0.02) and the superior nasal quadrant (p = 0.05). CONCLUSIONS: Our study demonstrated the feasibility of multispectral imaging to measure retinal changes in oxygenation in both SCD patients and matched volunteers. The results suggest that in SCD patients before any structural microvascular changes in the central retina are present, functional abnormalities can be observed with abnormal oximetry measurements.
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Anemia Falciforme/metabolismo , Oximetria/métodos , Consumo de Oxigênio/fisiologia , Oxigênio/metabolismo , Doenças Retinianas/metabolismo , Adolescente , Adulto , Anemia Falciforme/complicações , Anemia Falciforme/diagnóstico , Capilares/patologia , Feminino , Voluntários Saudáveis , Humanos , Macula Lutea/patologia , Masculino , Microvasos/patologia , Pessoa de Meia-Idade , Doenças Retinianas/diagnóstico , Doenças Retinianas/fisiopatologia , Tomografia de Coerência Óptica/métodos , Adulto JovemRESUMO
In the published online PDF version, Figure 3 was incorrectly captured the same as Figure 1.
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BACKGROUND: Assessment of treatment effects in clinical trials requires valid information on treatment adherence, adverse events and symptoms. Paper-based diaries are often inconvenient and have limited reliability, particularly for outpatient trials. OBJECTIVES: To investigate the utility of an electronic diary (e-diary) application for patients with skin diseases in outpatient clinical trials. METHODS: An e-diary application was developed and technically validated. Treatment adherence was defined as topical administration by the patient, and patient-reported outcomes, i.e. pain and itch, were evaluated by the e-diary in six clinical trials on newly tested topical drugs. Additionally, the proportion of patients capturing the applied topical drug by camera and filling in the pain and itch scores was defined as e-diary adherence, and patients' perception of usefulness and acceptability of the e-diary were evaluated. RESULTS: Treatment adherence rates of the included 256 patients were high (median 98%, range 97-99%). E-diary adherence was also high with a median of 93% (range 87-97%) for capturing the applied drug by camera, and 89% (range 87-96%) and 94% (range 87-96%) for entering respectively the itch and pain score. Daily symptom scores provided good insights into the disease burden, and patients rated the e-diary as good to excellent with respect to user acceptability. CONCLUSIONS: The results suggest that the e-diary is an excellent way to ensure proper treatment administration, indicated by both the high user acceptability scores and high treatment adherence. Moreover, the e-diary may also be valuable for frequent and reliable monitoring of patient-reported outcomes in daily clinical practice.
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Ensaios Clínicos como Assunto/normas , Diários como Assunto , Aplicativos Móveis , Medidas de Resultados Relatados pelo Paciente , Dermatopatias/tratamento farmacológico , Cooperação e Adesão ao Tratamento , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
The development of a new medicine is a risky and costly undertaking that requires careful planning. This planning is largely applied to the operational aspects of the development and less so to the scientific objectives and methodology. The drugs that will be developed in the future will increasingly affect pathophysiological pathways that have been largely unexplored. Such drug prototypes cannot be immediately introduced in large clinical trials. The effects of the drug on normal physiology, pathophysiology, and eventually the desired clinical effects will need to be evaluated in a structured approach, based on the definition of drug development as providing answers to important questions by appropriate clinical studies. This review describes the selection process for biomarkers that are fit-for-purpose for the stage of drug development in which they are used. This structured and practical approach is widely applicable and particularly useful for the early stages of innovative drug development.
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Biomarcadores Farmacológicos/análise , Descoberta de Drogas/métodos , Farmacologia/métodos , Animais , Relação Dose-Resposta a Droga , Cálculos da Dosagem de Medicamento , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/etiologia , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/prevenção & controle , Determinação de Ponto Final , Humanos , Segurança do Paciente , Farmacocinética , Medição de Risco , Fatores de Risco , Transdução de Sinais/efeitos dos fármacosRESUMO
Olaparib is used to treat BReast CAncer susceptibility protein (BRCA)-associated, platinum-sensitive ovarian cancer. Olaparib inhibits poly(ADP-ribose) polymerase, thereby blocking the repair of single-strand DNA breaks. This results in synthetic lethality in BRCA-associated cancer cells, which have a dysfunction of another DNA repair pathway - homologous recombination.
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Antineoplásicos/uso terapêutico , Neoplasias/tratamento farmacológico , Ftalazinas/uso terapêutico , Piperazinas/uso terapêutico , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Reparo do DNA/efeitos dos fármacos , Humanos , Ftalazinas/efeitos adversos , Ftalazinas/farmacologia , Piperazinas/efeitos adversos , Piperazinas/farmacologiaRESUMO
The aim of this study was to characterize a glucagon challenge test as a tool in diabetes research by assessing the inter- and intra-individual variability, and investigating the activity of the autonomic nervous system (ANS) during the challenge, as this might have an indirect impact on glucose homeostasis. The study was performed in 24 healthy volunteers separated in 2 groups. The first group of 12 volunteers underwent a 5-h glucagon challenge during a pancreatic clamp procedure with infusion of [6,6-2H2]-glucose infusion in combination with heart rate variability measurements. In the second group, 12 other healthy volunteers underwent two 6-h glucagon challenges separated by 6 weeks, and fat biopsies were taken for analysis of glucagon receptor expression. Serum glucose rose rapidly after glucagon infusion, and reached a plateau at 90 min. The time profiles suggested rapid development of tolerance for glucagon-induced hyperglycemia. During the glucagon challenge intra- and inter-individual variabilities for hepatic glucose production, the rate of disappearance of glucose, and plasma glucose were approximately 10-15% for all variables. Hyperglucagonemia did not affect heart rate variability. Human adipose tissue had a low, but variable, expression of glucagon receptor mRNA. This standardized glucagon challenge test has a good reproducibility with only limited variability over 6 weeks. It is a robust tool to explore in detail the contribution of glucagon in normal and altered glucose homeostasis and can also be used to evaluate the effects of drugs antagonizing glucagon action in humans without confounding changes in ANS tone.
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Glucagon/farmacologia , Farmacologia Clínica/métodos , Farmacologia Clínica/normas , Pesquisa , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Adolescente , Adulto , Glicemia/metabolismo , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Glucagon/sangue , Frequência Cardíaca/efeitos dos fármacos , Humanos , Fígado/metabolismo , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Glucagon/genética , Receptores de Glucagon/metabolismo , Padrões de Referência , Fatores de Tempo , Adulto JovemRESUMO
OBJECTIVE: Sleep deprivation is known to affect driving behavior and may lead to serious car accidents similar to the effects from e.g., alcohol. In a previous study, we have demonstrated that the use of machine learning techniques allows adequate characterization of abnormal driving behavior after alprazolam and/or alcohol intake. In the present study, we extend this approach to sleep deprivation and test the model for characterization of new interventions. We aimed to classify abnormal driving behavior after sleep deprivation, and, by using a machine learning model, we tested if this model could also pick up abnormal driving behavior resulting from other interventions. METHODS: Data were collected during a previous study, in which 24 subjects were tested after being sleep-deprived and after a well-rested night. Features were calculated from several driving parameters, such as the lateral position, speed of the car, and steering speed. In the present study, we used a gradient boosting model to classify sleep deprivation. The model was validated using a 5-fold cross validation technique. Next, probability scores were used to identify the overlap of driving behavior after sleep deprivation and driving behavior affected by other interventions. In the current study alprazolam, alcohol, and placebo are used to test/validate the approach. RESULTS: The sleep deprivation model detected abnormal driving behavior in the simulator with an accuracy of 77 ± 9%. Abnormal driving behavior after alprazolam, and to a lesser extent also after alcohol intake, showed remarkably similar characteristics to sleep deprivation. The average probability score for alprazolam and alcohol measurements was 0.79, for alcohol 0.63, and for placebo only 0.27 and 0.30, matching the expected relative drowsiness. CONCLUSION: We developed a model detecting abnormal driving induced by sleep deprivation. The model shows the similarities in driving characteristics between sleep deprivation and other interventions, i.e., alcohol and alprazolam. Consequently, our model for sleep deprivation may serve as a next reference point for a driving test battery of newly developed drugs.
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Acidentes de Trânsito/prevenção & controle , Atenção/fisiologia , Tempo de Reação/fisiologia , Privação do Sono/fisiopatologia , Adulto , Alprazolam/uso terapêutico , Condução de Veículo , Simulação por Computador/estatística & dados numéricos , GABAérgicos/uso terapêutico , Humanos , Aprendizado de Máquina , Masculino , Vigília/fisiologiaRESUMO
BACKGROUND: Digital devices and wearables allow for the measurement of a wide range of health-related parameters in a non-invasive manner, which may be particularly valuable in pediatrics. Incorporation of such parameters in clinical trials or care as digital endpoint could reduce the burden for children and their parents but requires clinical validation in the target population. This study aims to determine the tolerability, repeatability, and reference values of novel digital endpoints in healthy children. METHODS: Apparently healthy children (n = 175, 46% male) aged 2-16 were included. Subjects were monitored for 21 days using a home-monitoring platform with several devices (smartwatch, spirometer, thermometer, blood pressure monitor, scales). Endpoints were analyzed with a mixed effects model, assessing variables that explained within- and between-subject variability. Endpoints based on physical activity, heart rate, and sleep-related parameters were included in the analysis. For physical-activity-related endpoints, a sample size needed to detect a 15% increase was calculated. FINDINGS: Median compliance was 94%. Variability in each physical activity-related candidate endpoint was explained by age, sex, watch wear time, rain duration per day, average ambient temperature, and population density of the city of residence. Estimated sample sizes for candidate endpoints ranged from 33-110 per group. Daytime heart rate, nocturnal heart rate and sleep duration decreased as a function of age and were comparable to reference values published in the literature. CONCLUSIONS: Wearable- and portable devices are tolerable for pediatric subjects. The raw data, models and reference values presented here can be used to guide further validation and, in the future, clinical trial designs involving the included measures.
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Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Adolescente , Criança , Pré-Escolar , Exercício Físico/fisiologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Cooperação do Paciente , Valores de Referência , Reprodutibilidade dos Testes , Sono/fisiologia , Dispositivos Eletrônicos Vestíveis/tendênciasRESUMO
RATIONALE: Car-driving performance is negatively affected by the intake of alcohol, tranquillizers, sedatives and sleep deprivation. Although several studies have shown that the standard deviation of the lateral position on the road (SDLP) is sensitive to drug-induced changes in simulated and real driving performance tests, this parameter alone might not fully assess and quantify deviant or unsafe driving. OBJECTIVE: Using machine learning we investigated if including multiple simulator-derived parameters, rather than the SDLP alone would provide a more accurate assessment of the effect of substances affecting driving performance. We specifically analysed the effects of alcohol and alprazolam. METHODS: The data used in the present study were collected during a previous study on driving effects of alcohol and alprazolam in 24 healthy subjects (12 M, 12 F, mean age 26 years, range 20-43 years). Various driving features, such as speed and steering variations, were quantified and the influence of administration of alcohol or alprazolam was assessed to assist in designing a predictive model for abnormal driving behaviour. RESULTS: Adding additional features besides the SDLP increased the model performance for prediction of drug-induced abnormal driving behaviour (from an accuracy of 65 %-83 % after alprazolam intake and from 50 % to 76 % after alcohol ingestion). Driving behaviour influenced by alcohol and alprazolam was characterised by different feature importance, indicating that the two interventions influenced driving behaviour in a different way. CONCLUSION: Machine learning using multiple driving features in addition to the state-of-the-art SDLP improves the assessment of drug-induced abnormal driving behaviour. The created models may facilitate quantitative description of abnormal driving behaviour in the development and application of psychopharmacological medicines. Our models require further validation using similar and unknown interventions.
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Acidentes de Trânsito/prevenção & controle , Dirigir sob a Influência , Aprendizado de Máquina , Adulto , Simulação por Computador , Feminino , Humanos , Masculino , Desempenho Psicomotor/efeitos dos fármacos , Adulto JovemRESUMO
Benzodiazepines are effective short-term treatments for anxiety disorders, but their use is limited by undesirable side effects related to Central Nervous System impairment and tolerance development. SL65.1498 is a new compound that acts in vitro as a full agonist at the gamma-aminobutyric acid(A) 2 and 3 receptor and as a partial agonist at the 1 and 5 receptor subtypes. It is thought that the compound could be anxiolytic by its activation at the alpha2 and alpha3 receptor subtypes, without causing unfavourable side effects, which are believed to be mediated by the alpha1 and alpha5 subtypes. This study was a double-blind, five-way cross-over study to investigate the effects of three doses of SL65.1498 in comparison with placebo and lorazepam 2 mg in healthy volunteers. The objective was to select a dose level (expected to be therapeutically active), free of any significant deleterious effect. Psychomotor and cognitive effects were measured using a validated battery of measurements, including eye movements, body sway, memory tests, reaction-time assessments, and visual analogue scales. The highest dose of SL65.1498 showed slight effects on saccadic peak velocity and smooth pursuit performance, although to a much lesser extent than lorazepam. In contrast to lorazepam, none of the SL65.1498 doses affected body sway, visual analogue scale alertness, attention, or memory tests. This study showed that the three doses of SL65.1498 were well tolerated and induced no impairments on memory, sedation, psychomotor, and cognitive functions.
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Agonistas GABAérgicos/farmacologia , Agonistas GABAérgicos/farmacocinética , Moduladores GABAérgicos/farmacologia , Moduladores GABAérgicos/farmacocinética , Agonistas de Receptores de GABA-A , Indóis/farmacologia , Indóis/farmacocinética , Lorazepam/farmacologia , Lorazepam/farmacocinética , Pirróis/farmacologia , Pirróis/farmacocinética , Adulto , Atenção/efeitos dos fármacos , Cognição/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Movimentos Oculares/efeitos dos fármacos , Feminino , Agonistas GABAérgicos/efeitos adversos , Moduladores GABAérgicos/efeitos adversos , Humanos , Indóis/efeitos adversos , Lorazepam/efeitos adversos , Masculino , Memória/efeitos dos fármacos , Testes Neuropsicológicos , Equilíbrio Postural/efeitos dos fármacos , Acompanhamento Ocular Uniforme/efeitos dos fármacos , Pirróis/efeitos adversos , Receptores de GABA-A , Movimentos Sacádicos/efeitos dos fármacos , Adulto JovemRESUMO
CB1/CB2 agonists are reported to have sedative, amnestic, analgesic and anti-emetic properties, which would make them ideal drugs for outpatient treatments under conscious sedation. The main objective of this in human study was to assess the sedative properties of Org 28611, a potent water-soluble CB1 agonist. Single ascending doses were administered during a slow 25 min infusion and after a 1 min bolus administration to healthy male volunteers. In addition, the pharmacokinetics, amnestic properties, postural stability, electro-encephalography, behavioural and cardiovascular effects were studied. Midazolam 0.1 mg/kg was used as a positive control. The pharmacokinetic parameters were proportional to dose. No effects were observed after intravenous administration of doses up to Org 28611 1 microg/kg. Dose-related effects were observed at higher doses. Although subjects reported subjective sedation after administration of Org 28611 3-10 microg/kg, the observed sedation was considerably less than after midazolam. Org 28611 is, therefore, not suitable for providing sedation for outpatient surgical procedures and doses above the maximum tolerated dose of 3 microg/kg (either administered as a slow infusion or a bolus dose) can cause untoward psychotropic effects.
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Receptor CB1 de Canabinoide/agonistas , Adulto , Afeto/efeitos dos fármacos , Contagem de Células Sanguíneas , Pressão Sanguínea/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Eletrocardiografia/efeitos dos fármacos , Eletroencefalografia/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Humanos , Injeções Intravenosas , Masculino , Oxigênio/sangue , Equilíbrio Postural/efeitos dos fármacos , Movimentos Sacádicos/efeitos dos fármacos , Aprendizagem Verbal/efeitos dos fármacos , Percepção Visual/efeitos dos fármacos , Adulto JovemRESUMO
RWJ-800088 is a novel thrombopoietin mimetic peptide for the treatment of thrombocytopenia. The objectives of this study were to evaluate the pharmacokinetics, pharmacodynamics, and safety of ascending doses of RWJ-800088 administered as a single intravenous delivery in a double-blind, placebo-controlled study with five parallel groups of eight healthy human subjects each. Platelet counts and functionality, peripheral stem cells, drug concentrations, and routine laboratory parameters were measured frequently up to day 29, and antibody formation was measured up to days 56-72. At doses > or = 0.75 microg/kg of RWJ-800088, platelet levels showed dose-related elevation as compared to results with placebo. The pharmacokinetic profile was characterized for doses of 2.5 and 3.0 microg/kg, although the dose relationship could not be fully defined. The two highest doses of RWJ-800088 appeared to increase burst-forming units-erythroid and colony-forming unit counts, suggesting some effects on progenitor lineages. RWJ-800088 was well tolerated, with no evidence of antibody formation in this single-dose study. Additional patient studies are warranted to investigate the therapeutic use of this novel peptide.
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Peptídeos/farmacologia , Células-Tronco/efeitos dos fármacos , Trombopoetina/agonistas , Adulto , Relação Dose-Resposta a Droga , Método Duplo-Cego , Células Precursoras Eritroides/efeitos dos fármacos , Eritropoetina/sangue , Humanos , Injeções Intravenosas , Peptídeos e Proteínas de Sinalização Intercelular , Masculino , Pessoa de Meia-Idade , Peptídeos/efeitos adversos , Peptídeos/farmacocinética , Contagem de Plaquetas , Fator de Crescimento Derivado de Plaquetas/análise , Trombopoetina/sangue , Fator de Crescimento Transformador beta/sangueRESUMO
INTRODUCTION: The clinical assessment of the myocardial damage caused by anthracyclin (ANT)-therapy is difficult. Therefore a study was performed to evaluate non-invasive markers of anthracyclin-induced cardiac effects, with emphasis on course-to-course variation. METHODS: Eligible for study participation were patients, without known cardiologic abnormalities who did not use cardiotoxic medication (except for ANT-therapy), who had previously completed at least three cycles of anthracyclin-containing chemotherapy (n = 14) and patients who were ANT-naïve and who were scheduled to receive doxorubicin-containing chemotherapy (n = 12). Seven patients in this last group also completed at least three cycles and were available for follow-up assessments; thus a total population of 21 patients (12F/9M) completed at least three courses ANT-chemotherapy. In these patients blood samples and ECG-recordings were taken within 6 months after completion of ANT-therapy. In 12 patients (10F/2M) assessments were also done before, immediately afterwards and at 24 h after each course of ANT. RESULTS AND CONCLUSIONS: In the patients who completed chemotherapy, NT-proBNP was 277% (n = 21; 95% CI: 86-661%, P < 0.001) higher compared to healthy volunteers. During the first course NT-proBNP rose 269% (n = 12; 167-409%, P < 0.0001) at 24 h post-administration. The linear corrected QT (QTcL) directly after the first administration of ANT increased by 9.56 ms (n = 12; 3.85-15.27, P < 0.001) and this prolongation was still present at 24 h, 11.48 ms (n = 12; 5.61-17.34, P < 0.0001). Both NT-proBNP and QTcL returned to baseline before the start of the next course and a similar pattern was observed during each course. NT-proBNP and QTcL may be useful markers for course-to-course evaluation of anthracyclin-induced cardiotoxicity.
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Antraciclinas/efeitos adversos , Doenças Cardiovasculares/induzido quimicamente , Biomarcadores/sangue , Eletrocardiografia , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
AIM: To study the pharmacokinetics (PK), safety and tolerability of single rising doses up to 80 mg of superoxide dismutase covalently linked to lecithin (PC-SOD) in healthy White volunteers. METHODS: This double-blind, placebo-controlled, four-period cross-over study was performed in eight healthy volunteers (four male/four female). Three doses of PC-SOD (20, 40 and 80 mg) and placebo were administered intravenously in randomized order. Serum and urinary PC-SOD concentrations were measured predose and up to 96 h after dosing. In addition to standard safety measurements, the urinary excretion of N-acetyl-beta-glucosaminidase, alpha-glutathione S-transferase (alpha-GST) and pi-GST was measured to evaluate renal function. The PK of PC-SOD was analysed using noncompartmental and compartmental methods. RESULTS: All treatments were well tolerated, and no obvious relationship between adverse events and treatment was observed. No effects of PC-SOD on renal function could be detected. Dose normalized C(max) and AUC were not different between the different dosages, indicating linearity of plasma concentrations with dose. Estimated PC-SOD clearance was 2.54 ml min(-1)[95% confidence interval (CI) 2.07, 2.83]. The terminal half-life was estimated to be 1.54 days (95% CI 0.93, 2.15). SOD activity was elevated above baseline for 19 +/- 6 h after the 80-mg dose. CONCLUSIONS: Single intravenous administrations of PC-SOD in doses up to 80 mg were well tolerated in healthy White male and female volunteers. With the doses used, SOD activity was linearly related to the dose; after the 80-mg dose it was present for an appreciable period. These findings suggest that it is worthwhile to investigate PC-SOD in clinical conditions characterized by a high radical overload.
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Sequestradores de Radicais Livres/administração & dosagem , Sequestradores de Radicais Livres/farmacocinética , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/administração & dosagem , Superóxido Dismutase/farmacocinética , Adolescente , Adulto , Área Sob a Curva , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/farmacologia , Método Duplo-Cego , Feminino , Sequestradores de Radicais Livres/farmacologia , Humanos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Superóxido Dismutase/farmacologiaRESUMO
This randomised, double-blind, placebo-controlled, cross-over study was designed to identify which pharmacodynamic parameters most accurately quantify the effects of delta-9-Tetrahydrocannabinol (THC), the predominantly psychoactive component of cannabis. In addition, we investigated the acceptability and usefulness of a novel mode of intrapulmonary THC administration using a Volcano vaporizer and pure THC instead of cannabis. Rising doses of THC (2, 4, 6 and 8 mg) or vehicle were administered with 90 minutes intervals to twelve healthy males using a Volcano vaporizer. Very low between-subject variability was observed in THC plasma concentrations, characterising the Volcano vaporizer as a suitable method for the administration of THC. Heart rate showed a sharp increase and rapid decline after each THC administration (8 mg: 19.4 bpm: 95% CI 13.2, 25.5). By contrast, dose dependent effects of body sway (8 mg: 108.5%: 95% CI 72.2%, 152.4%) and different subjective parameters did not return to baseline between doses (Visual Analogue Scales of 'alertness' (8 mg: -33.6 mm: 95% CI -41.6, -25.7), 'feeling high' (8 mg: 1.09 U: 95% CI 0.85, 1.33), 'external perception' (8 mg: 0.62 U: 95% CI 0.37, 0.86)). PK/PD-modeling of heart rate displayed a relatively short equilibration half-life of 7.68 min. CNS parameters showed equilibration half-lives ranging between 39.4 - 84.2 min. Some EEG-frequency bands, and pupil size showed small changes following the highest dose of THC. No changes were seen in saccadic eye movements, smooth pursuit and adaptive tracking performance. These results may be applicable in the development of novel cannabinoid agonists and antagonists, and in studies of the pharmacology and physiology of cannabinoid systems in humans.
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Dronabinol/administração & dosagem , Dronabinol/farmacologia , Alucinógenos/administração & dosagem , Alucinógenos/farmacologia , Administração por Inalação , Adulto , Aerossóis , Pressão Sanguínea/efeitos dos fármacos , Sistema Nervoso Central/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Dronabinol/farmacocinética , Eletroencefalografia/efeitos dos fármacos , Alucinógenos/farmacocinética , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Percepção/efeitos dos fármacos , Equilíbrio Postural/efeitos dos fármacos , Desempenho Psicomotor/efeitos dos fármacos , Pupila/efeitos dos fármacos , Acompanhamento Ocular Uniforme/efeitos dos fármacos , Movimentos Sacádicos/efeitos dos fármacos , Adulto JovemRESUMO
Pharmacokinetics after pulmonary administration of delta-9-tetrahydrocannabinol (THC) and its major metabolites 11-OH-THC and 11-nor-9-COOH-THC was quantified. Additionally, the relationship between THC and its effects on heart rate, body sway and several visual analogue scales was investigated using pharmacokinetic-pharmacodynamic (PK-PD) modelling. This provided insights useful for the research and development of novel cannabinoids and the physiology and pharmacology of cannabinoid systems. First, the PK-PD model gave information reflecting various aspects of cannabinoid systems. The delay between THC concentration and effect was quantified in equilibration half-lives of 7.68 min for heart rate and from 39.2 to 84.8 min for the CNS responses. This suggests that the effect of THC on the different responses could be due to different sites of action or different physiological mechanisms. Differences in the shape of the concentration-effect relationship could indicate various underlying mechanisms. Second, the PK-PD model can be used for prediction of THC concentration and effect profiles. It is illustrated how this can be used to optimise studies with entirely different trial designs. Third, many new cannabinoid agonists and antagonists are in development. PK-PD models for THC can be used as a reference for new agonists or as tools to quantitate the pharmacological properties of cannabinoid antagonists.
Assuntos
Canabinoides/farmacologia , Sistema Nervoso Central/efeitos dos fármacos , Dronabinol/farmacologia , Alucinógenos/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Administração por Inalação , Adulto , Aerossóis , Pressão Sanguínea/efeitos dos fármacos , Relação Dose-Resposta a Droga , Método Duplo-Cego , Dronabinol/administração & dosagem , Eletroencefalografia/efeitos dos fármacos , Meia-Vida , Alucinógenos/administração & dosagem , Humanos , Masculino , Modelos Estatísticos , Dinâmica não Linear , Percepção/efeitos dos fármacos , Equilíbrio Postural/efeitos dos fármacos , Desempenho Psicomotor/efeitos dos fármacos , Pupila/efeitos dos fármacos , Acompanhamento Ocular Uniforme/efeitos dos fármacos , Movimentos Sacádicos/efeitos dos fármacos , Adulto JovemRESUMO
The use of non-selective gamma-aminobutyric acid (GABA) enhancers, such as benzodiazepines in the treatment of anxiety disorders is still widespread but hampered by unfavourable side effects. some of these may be associated with binding properties to certain subtypes of the GABA(A) receptor that are unnecessary for therapeutic effects. MK-0343 was designed to be a less sedating anxiolytic, based on reduced efficacy at the alpha1 subtype and significant efficacy at alpha2 and alpha3 subtypes of the GABA(A) receptor. This paper is a double-blind, four-way cross-over (n = 12) study to investigate the effects of MK-0343 (0.25 and 0.75 mg) in comparison to placebo and an anxiolytic dose (2 mg) of the non-selective agonist lorazepam. Effects were measured by eye movements, body sway, Visual Analogue scales (VAS) and memory tests. Lorazepam impaired saccadic peak velocity (SPV), VAs alertness scores, postural stability and memory and increased saccadic latency and inaccuracy. MK-0343 0.75 mg was equipotent with lorazepam as indicated by SPV (-42.4 deg/s), saccadic latency (0.02 s) and VAS alertness scores (1.50 ln mm), while effects on memory and postural stability were smaller. MK-0343 0.25 mg only affected postural stability to a similar extent as MK-0343 0.75 mg. The effect profile of MK-0343 0.75 mg is different from the full agonist lorazepam, which could reflect the selective actions of this compound. Although less effect on VAS alertness was expected, diminished effects on memory and postural stability were present. Clinical studies in anxiety patients should show whether this dose of MK-0343 is therapeutically effective with a different side-effect profile.
Assuntos
Ansiolíticos/farmacologia , Agonistas de Receptores de GABA-A , Lorazepam/farmacologia , Adolescente , Adulto , Ansiolíticos/farmacocinética , Cognição/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Humanos , Masculino , Medição da Dor , Piridazinas/farmacologia , Movimentos Sacádicos/efeitos dos fármacos , Triazóis/farmacologiaRESUMO
The neovascular ('wet') form of age-related macular degeneration (AMD) is characterized by vascular growth and leakage in the retina. Two new drugs, pegaptanib and ranibizumab, have been shown to improve vision or slow the progression of AMD. Both drugs inhibit the action of vascular endothelial growth factor--pegaptanib as an oligonucleotide and ranibizumab as a monoclonal antibody--thereby decreasing angiogenesis in the eye. Adverse effects are associated with the intravitreal administration of both drugs and include increased intraocular pressure, local bleeding, and infection.