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The purpose of this study was to assess the safety, tolerability, pharmacokinetics, pharmacodynamics, and immunogenicity of BOS161721, a humanized immunoglobulin G1 triple mutation (M252Y/S254T/T256E) monoclonal antibody that inhibits interleukin-21 (IL-21) bioactivity. This randomized, single-center, double-blind, placebo-controlled study randomized healthy volunteers 3:1 to single ascending intravenous and subcutaneous doses of BOS161721 (range 1-240 mg) or placebo. BOS161721 and placebo groups had similar rates of adverse events, mostly mild; none led to study discontinuation. There were no clinically significant findings in physical examination, vital signs, or laboratory assessment. In the pooled BOS161721 population, four subjects (8.5%) tested antidrug antibody-positive predose, and seven (14.9%) postdose. Absolute CD4+ lymphocyte count remained normal throughout follow-up. BOS161721 administered subcutaneously was absorbed slowly, with a median time to maximum concentration (Tmax ) of 144 hours across doses (range 1-15 days) and a mean apparent terminal elimination half-life of 80-87 days for doses ≥ 30 mg. Area under the concentration-time curve from time zero to infinity (AUC0-inf ) and maximum observed concentration (Cmax ) were linear across doses > 10 mg. Subcutaneous bioavailability was 64%. Phosphorylated signal transducer and activator of transcription 3 (pSTAT3) decreased dose-dependently with threshold characteristics at doses of ≥ 10 mg. Downregulation in BATF, IL6, LAG3, and SOCS3 genes caused by IL-21 stimulation was reversed dose-dependently. BOS161721 was well-tolerated across doses, suppressed IL-21-induced pSTAT3 dose-dependently, and reversed downregulation of genes critical to tolerance induction and T-cell exhaustion induced by IL-21. Further clinical studies are ongoing in patients with systemic lupus erythematosus, in which IL-21 has a pathogenetic role.

Introduction Tafenoquine has been recently registered for the prevention of relapse in Plasmodium vivax malaria. Objective This study assessed the pharmacodynamic effects of 300-mg single-dose tafenoquine on the retina. Methods This phase I, prospective, multicenter, randomized, single-masked, placebo-controlled, parallel-group study was conducted between 2 February 2016 and 14 September 2017 at three US study centers. Adult healthy volunteers were randomized (2:1) to receive either a single 300-mg oral dose of tafenoquine or matched placebo on day 1. Ophthalmic assessments, including spectral domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF), were conducted at baseline and day 90 and evaluated for pre-determined endpoints by an independent, masked reading center. Results One subject in each group met the composite primary endpoint for retinal changes identified with SD-OCT or FAF, i.e., one out of 306 (0.3%) with tafenoquine, one out of 161 (0.6%) with placebo. Both cases had unilateral focal ellipsoid zone disruption at day 90 with no effect on best-corrected visual acuity. The tafenoquine-treated subject had this abnormality at baseline, and was enrolled in error. There was no difference in ophthalmic safety between tafenoquine and placebo. Conclusion There was no evidence of any pharmacodynamic effect of 300-mg single-dose tafenoquine on the retina or any short-term clinically relevant effects on ophthalmic safety. This clinical trial is registered with ClinicalTrials.gov (identifier: NCT02658435). Electronic supplementary material The online version of this article (10.1007/s40264-019-00839-w) contains supplementary material, which is available to authorized users.

Background The Airways Disease Endotyping for Personalized Therapeutics (ADEPT) study profiled patients with mild, moderate, and severe asthma and nonatopic healthy control subjects. Objective We explored this data set to define type 2 inflammation based on airway mucosal IL-13–driven gene expression and how this related to clinically accessible biomarkers. Methods IL-13–driven gene expression was evaluated in several human cell lines. We then defined type 2 status in 25 healthy subjects, 28 patients with mild asthma, 29 patients with moderate asthma, and 26 patients with severe asthma based on airway mucosal expression of (1) CCL26 (the most differentially expressed gene), (2) periostin, or (3) a multigene IL-13 in vitro signature (IVS). Clinically accessible biomarkers included fraction of exhaled nitric oxide (Feno) values, blood eosinophil (bEOS) counts, serum CCL26 expression, and serum CCL17 expression. Results Expression of airway mucosal CCL26, periostin, and IL-13–IVS all facilitated segregation of subjects into type 2–high and type 2–low asthmatic groups, but in the ADEPT study population CCL26 expression was optimal. All subjects with high airway mucosal CCL26 expression and moderate-to-severe asthma had Feno values (≥35 ppb) and/or high bEOS counts (≥300 cells/mm 3 ) compared with a minority (36%) of subjects with low airway mucosal CCL26 expression. A combination of Feno values, bEOS counts, and serum CCL17 and CCL26 expression had 100% positive predictive value and 87% negative predictive value for airway mucosal CCL26–high status. Clinical variables did not differ between subjects with type 2–high and type 2–low status. Eosinophilic inflammation was associated with but not limited to airway mucosal type 2 gene expression. Conclusion A panel of clinical biomarkers accurately classified type 2 status based on airway mucosal CCL26, periostin, or IL-13–IVS gene expression. Use of Feno values, bEOS counts, and serum marker levels (eg, CCL26 and CCL17) in combination might allow patient selection for novel type 2 therapeutics.

The originator abiraterone acetate (OAA) formulation is used for the treatment of metastatic castration-resistant prostate cancer (mCRPC). This study evaluated the bioavailability and bioequivalence of a novel formulation, abiraterone acetate fine particle (AAFP), versus OAA on a steady-state background of steroids. Thirty-seven healthy male subjects were randomized in a crossover design to receive methylprednisolone (4 mg twice daily) or prednisone (5 mg twice daily) for 12 days in Period 1. On Day 11 of Period 1, subjects given methylprednisolone received a single dose of AAFP 500 mg, and subjects given prednisone received a single dose of OAA 1000 mg under fasted conditions. After a 2-week steroid washout period, subjects received the alternate treatments in Period 2. There were no statistical differences regarding area under the curve (AUC) and maximum concentration (C max) between AAFP and OAA. The bioavailability of abiraterone from AAFP versus OAA by geometric mean ratio was AUC0–∞, 95.9% (90% confidence interval [CI] 86.0–106.9); AUC0–t , 99.2% (88.7–110.9); and C max, 116.8% (102.2–133.4). The coefficient of variation (CV) was smaller for AAFP versus OAA (AUC0–∞, CV 44.23 vs. 55.61%; AUC0–t , 45.17 vs. 58.16%; C max, 54.55 vs. 65.65%, respectively). Both treatments were safe and well tolerated. AAFP plus methylprednisolone provided abiraterone exposure that was comparable to OAA plus prednisone with respect to C max and AUC. Less drug exposure variability was observed with AAFP compared with OAA. Reduced pharmacokinetic variability may positively influence clinical outcomes and warrants further study in mCRPC patients.

Background and Objective Abiraterone acetate is approved for the treatment of metastatic castration-resistant prostate cancer. The originator abiraterone acetate (OAA) formulation is poorly absorbed and exhibits large pharmacokinetic variability in abiraterone exposure. Abiraterone acetate fine particle (AAFP) is a proprietary formulation (using SoluMatrix Fine Particle Technology™) designed to increase the oral bioavailability of abiraterone acetate. Here, we report on two phase I studies in healthy male subjects aged 18–50 years. Methods In Study 101, 20 subjects were randomized in a crossover design to single doses of AAFP 100, 200, or 400 mg or OAA 1000 mg taken orally under fasting conditions. Results suggested that AAFP 500 mg would be bioequivalent to OAA 1000 mg in the fasted state. To confirm the bioequivalence hypothesis and to further expand the AAFP dose range, in Study 102, 36 subjects were randomized in a crossover design to single doses of AAFP 125, 500, or 625 mg or OAA 1000 mg. Both studies included a 7-day washout period between administrations. Results Dose-dependent increases in the area under the plasma concentration–time curve and maximum plasma concentration with AAFP were observed in both studies. The AAFP 500-mg bioavailability relative to OAA 1000 mg measured by the geometric mean ratio for area under the plasma concentration–time curve from time zero to the time of the last quantifiable concentration was 93.4% (90% confidence interval 85.3–102.4), area under the plasma concentration–time curve from time zero to infinity was 91.0% (90% confidence interval 83.3–99.4), and maximum plasma concentration was 99.8% (90% confidence interval 86.3–115.5). Dose proportionality was seen across all AAFP dose levels (100–625 mg). Abiraterone acetate fine particle was found to be safe and well tolerated in this study. Conclusion Abiraterone acetate fine particle 500 mg was demonstrated to be bioequivalent to OAA 1000 mg in healthy volunteers under fasted conditions. Electronic supplementary material The online version of this article (doi:10.1007/s40262-017-0536-2) contains supplementary material, which is available to authorized users.

Tafenoquine is in development as a single-dose treatment for relapse prevention in individuals with Plasmodium vivax malaria. Tafenoquine must be coadministered with a blood schizonticide, either chloroquine or artemisinin-based combination therapy (ACT). This open-label, randomized, parallel-group study evaluated potential drug interactions between tafenoquine and two ACTs: dihydroartemisinin-piperaquine and artemether-lumefantrine. Healthy volunteers of either sex aged 18 to 65 years without glucose-6-phosphate dehydrogenase deficiency were randomized into five cohorts ( n = 24 per cohort) to receive tafenoquine on day 1 (300 mg) plus once-daily dihydroartemisinin-piperaquine on days 1, 2, and 3 (120 mg/960 mg for 36 to C max ) comparisons of tafenoquine plus ACT versus tafenoquine or ACT. All subjects receiving dihydroartemisinin-piperaquine experienced QTc prolongation (a known risk with this drug), but tafenoquine coadministration had no clinically relevant additional effect. Tafenoquine coadministration had no clinically relevant effects on dihydroartemisinin, piperaquine, artemether, or lumefantrine pharmacokinetics. Dihydroartemisinin-piperaquine coadministration increased the tafenoquine C max by 38% (90% confidence interval, 25 to 52%), the AUC from time zero to infinity (AUC 0–∞ ) by 12% (1 to 26%), and the half-life ( t 1/2 ) by 29% (19 to 40%), with no effect on the AUC from time zero to the time of the last nonzero concentration (AUC 0–last ). Artemether-lumefantrine coadministration had no effect on tafenoquine pharmacokinetics. Tafenoquine can be coadministered with dihydroartemisinin-piperaquine or artemether-lumefantrine without dose adjustment for any of these compounds. (This study has been registered at ClinicalTrials.gov under registration no. NCT02184637.)

INTRODUCTION Doravirine, a non-nucleoside reverse-transcriptase inhibitor in development for the treatment of patients with human immunodeficiency virus-1 infection, has potential to be used concomitantly in antiretroviral therapy with dolutegravir, an integrase strand transfer inhibitor. The pharmacokinetic interactions between these drugs were therefore assessed. METHODS Oral formulations of doravirine and dolutegravir were dosed both individually and concomitantly once daily in healthy adults. Twelve subjects (six were male), 23-42 years of age, were enrolled and 11 completed this phase I, open-label, three-period, fixed-sequence study per protocol; one subject was discontinued for a positive cotinine test at admission to period 2. In period 1, dolutegravir 50 mg was administered for 7 days. After a 7-day washout, doravirine 200 mg was dosed for 7 days in period 2, followed (without washout) by both doravirine and dolutegravir simultaneously for 7 days in period 3. Plasma samples were taken to determine dolutegravir and doravirine concentrations. RESULTS The steady-state concentration 24 h post-dose (C24) of dolutegravir was not substantially altered by co-administration of doravirine multiple doses; area under the plasma concentration-time curve from dosing to 24 h post-dose (AUC0-24), maximum concentration (C max), and C24 geometric mean ratios were 1.36, 1.43, and 1.27, respectively. The pharmacokinetics of doravirine was not affected by multiple doses of dolutegravir (geometric mean ratios: 1.00, 0.98, and 1.06 for AUC0-24, C24, and C max, respectively). Both drugs were generally well tolerated. CONCLUSION The results of this study demonstrate that concomitant administration of doravirine and dolutegravir in healthy subjects causes no clinically significant alteration in the pharmacokinetic and safety profiles of the two drugs, thereby supporting further evaluation of co-administration of these agents for human immunodeficiency virus-1 treatment.

SoluMatrix® meloxicam has been developed using SoluMatrix Fine Particle Technology™ to produce a meloxicam drug product with enhanced absorption properties to enable treatment at lower doses than available oral meloxicam drug products. This follows recognition of serious dose-dependent adverse events (AEs) associated with nonsteroidal anti-inflammatory drugs, including meloxicam. This study investigated the pharmacokinetic (PK) properties of SoluMatrix meloxicam 5-mg (fasting conditions) and 10-mg capsules (fasting and fed conditions) and compared SoluMatrix meloxicam 10-mg capsules with meloxicam 15-mg tablets under fasting conditions. This four-period crossover study randomized 28 healthy adult participants to receive single doses of SoluMatrix meloxicam 5-mg capsules (fasting) and 10-mg capsules (fasting or fed) and meloxicam tablets 15 mg (fasting). Meloxicam plasma concentrations were assessed through 96 h postdose. Safety was assessed. Twenty-five participants (89.3 %) completed the study. Under fasting conditions, SoluMatrix meloxicam 10 mg [1252.8 (254.22) ng/mL] produced similar meloxicam mean (standard deviation (SD)) maximum plasma concentrations vs meloxicam 15-mg tablets [1288.8 (424.40) ng/mL]. The overall mean (SD) systemic meloxicam exposure was 33 % lower for SoluMatrix meloxicam 10 mg [29,173.01 (11,042.09) ng*h/mL] vs meloxicam 15-mg tablets [40,875.6 (11,733.47) ng*h/mL]. The median time to maximum plasma meloxicam levels occurred earlier following SoluMatrix meloxicam 5 mg (2.0 h) and 10 mg (2.0 h) administration vs meloxicam 15-mg tablets (4.0 h). Few study-medication-related AEs were reported. SoluMatrix meloxicam 10 mg was more rapidly absorbed and associated with a lower overall exposure compared with meloxicam 15-mg tablets in this study in healthy adults under fasting conditions.

Doravirine is a novel HIV-1 non-nucleoside reverse transcriptase inhibitor exhibiting a robust safety and efficacy profile in combination with other antiretrovirals. While existing data do not suggest that doravirine delays cardiac repolarization, the aim of this trial was to evaluate the effects of a supratherapeutic dose of doravirine on the heart-rate corrected QT (QTc) interval in healthy adults. A randomized, three-period, crossover, placebo-controlled trial was conducted in healthy adults, 18–55 years of age. Three treatments were administered: single-dose doravirine 1200 mg, placebo, and positive control (single-dose moxifloxacin 400 mg). QT interval measurements were collected at serial time points following treatment administration. Clinically significant placebo-corrected, baseline-adjusted QTc interval prolongation was defined when the upper bound of the two-sided 90% confidence interval (CI) for the mean effect on double delta QTc exceeded 10 ms. Doravirine tolerability and pharmacokinetics were also evaluated. Forty-five subjects were enrolled and 39 completed the study per protocol. Fridericia’s QT correction for heart rate was demonstrated to be inadequate; therefore, a population-specific correction was applied (QTcP). Assay sensitivity was confirmed with moxifloxacin. Following doravirine administration, QTc intervals did not exceed the pre-specified significance threshold – upper 90% CIs were ≤5.42 ms across all time points. Categorical analyses identified no outliers or clinically meaningful deviations. Doravirine geometric mean area under the time-concentration curve from dosing until 24 h post-dose (AUC0–24) and maximum plasma concentration (C max) were 119 µM·h and 9240 nM, respectively, which exceeded values expected following therapeutic dose administration of doravirine 100 mg, even in the setting of intrinsic and extrinsic factors that may cause increases in doravirine concentrations. All treatments were generally well tolerated. A single oral supratherapeutic dose of doravirine 1200 mg does not cause clinically meaningful QTc interval prolongation in healthy adults.

The glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) exenatide and lixisenatide reduce cholecystokinin (CCK)-induced gallbladder emptying in healthy subjects. It is unknown if all GLP-1 RAs share this effect; therefore, the effect of the GLP-1 RA albiglutide on gallbladder function was assessed. In this randomized, double-blind, 2-way crossover study, a single dose of subcutaneous albiglutide 50 mg or placebo was administered to 17 healthy subjects, and CCK-induced gallbladder contractility was measured by ultrasonography. CCK (0.003 μg/kg) was infused intravenously over 50 minutes on study day 4 (3 days after dosing, to coincide with albiglutide's expected time to maximum concentration). Gallbladder volume, ejection fraction, and the main pancreatic and common bile-duct diameters were measured before, during, and following CCK infusion. Gallbladder volume was significantly greater in the albiglutide vs placebo groups before, during, and after CCK infusion, and the mean difference from placebo increased numerically during CCK infusion. The area under the volume-effect curve was significantly greater with albiglutide (P = .029). Starting at the 30-minute CCK infusion time point, the gallbladder ejection fraction was significantly lower with albiglutide than placebo. Changes in pancreatic duct diameter and common bile-duct diameter were not significantly different between albiglutide and placebo. Similar incidences of adverse events were observed between the albiglutide and placebo treatment periods. No new albiglutide safety signals were detected, and no serious adverse events were reported. In conclusion, similar to other GLP-1 RAs, albiglutide decreased CCK-induced gallbladder emptying compared with placebo in healthy individuals. Clinical implications of the gallbladder effects are unclear at this time.

Tafenoquine is being developed for relapse prevention in Plasmodium vivax malaria. This Phase I, single-blind, randomized, placebo- and active-controlled parallel group study investigated whether tafenoquine at supratherapeutic and therapeutic concentrations prolonged cardiac repolarization in healthy volunteers. Subjects aged 18-65 years were randomized to one of five treatment groups (n = 52 per group) to receive placebo, tafenoquine 300, 600, or 1200 mg, or moxifloxacin 400 mg (positive control). Lack of effect was demonstrated if the upper 90% CI of the change from baseline in QTcF following supratherapeutic tafenoquine 1200 mg versus placebo (ΔΔQTcF) was10 milliseconds for all pre-defined time points. The maximum ΔΔQTcF with tafenoquine 1200 mg (n = 50) was 6.39 milliseconds (90% CI 2.85, 9.94) at 72 hours post-final dose; that is, lack of effect for prolongation of cardiac depolarization was demonstrated. Tafenoquine 300 mg (n = 48) or 600 mg (n = 52) had no effect on ΔΔQTcF. Pharmacokinetic/pharmacodynamic modeling of the tafenoquine-QTcF concentration-effect relationship demonstrated a shallow slope (0.5 ms/μg mL(-1) ) over a wide concentration range. For moxifloxacin (n = 51), maximum ΔΔQTcF was 8.52 milliseconds (90% CI 5.00, 12.04), demonstrating assay sensitivity. In this thorough QT/QTc study, tafenoquine did not have a clinically meaningful effect on cardiac repolarization.

This study evaluated the effects of either famotidine or antacid on the pharmacokinetics of nilotinib in healthy subjects, with the specific focus to explore different dosing separation schemes leading to a minimized drug–drug interaction. Fifty-two subjects were randomized to receive the following treatments in a crossover manner: (A) single oral nilotinib 400 mg alone; (B) famotidine 20 mg twice a day for 3 days, followed by a single administration of nilotinib 400 mg and famotidine 20 mg on Day 4, where famotidine was given 2 h after nilotinib; (C) single oral nilotinib 400 mg and antacid suspension 20 mL, where antacid was given 2 h before nilotinib; (D) single oral nilotinib 400 mg and antacid suspension 20 mL, where antacid was given 2 h after nilotinib. Comparing Treatment B to Treatment A, the geometric mean ratios of nilotinib C max, AUC0-tlast, and AUC0-inf were 0.966, 0.984, and 0.911, respectively (90 % confidence intervals (CIs), 0.875–1.066, 0.905–1.069, and 0.798–1.039, respectively). Nilotinib pharmacokinetic parameters following Treatment C or Treatment D were similar to those after Treatment A; the corresponding 90 % CIs of the geometric mean ratios of C max, AUC0-tlast, and AUC0-inf all fell within the bioequivalence range of 0.8–1.25. Neither famotidine nor antacid significantly affected nilotinib pharmacokinetics. When concurrent use of an H2 blocker or an antacid is necessary, the H2 blocker may be administered 10 h before and 2 h after nilotinib dose, or the antacid may be administered 2 h before or 2 h after nilotinib dose.

Eltrombopag is an orally bioavailable thrombopoietin receptor agonist approved for the treatment of thrombocytopenia associated with chronic immune (idiopathic) thrombocytopenic purpura and chronic hepatitis C virus (HCV) infection. This study evaluated the potential drug-drug interactions between eltrombopag and the HCV protease inhibitors boceprevir and telaprevir. In this open-label, 3-period, single-sequence, and crossover study, 56 healthy adult subjects were randomized 1:1 to cohort 1 (boceprevir) or 2 (telaprevir). The dosing was as follows: period 1, single 200-mg dose of eltrombopag; period 2, 800 mg boceprevir or 750 mg telaprevir every 8 hours (q8h) for 10 days; and period 3, single 200-mg dose of eltrombopag with either 800 mg boceprevir or 750 mg telaprevir q8h (3 doses). All doses were administered with food, and eltrombopag was administered specifically with low-calcium food. There was a 3-day washout between periods 1 and 2 and no washout between periods 2 and 3. Serial pharmacokinetic samples were collected for 72 h in periods 1 and 3 and for 8 h in period 2. The coadministration of eltrombopag increased the rate of boceprevir absorption, resulting in a 20% increase in the maximum concentration in plasma (Cmax), a 1-h-earlier time to Cmax (Tmax) for boceprevir, a 32% decrease in the concentration at the end of the dosing interval (Cτ), and no change in the area under the concentration-time curve over the dosing interval (AUC0-τ). The coadministration of eltrombopag did not alter telaprevir pharmacokinetics, and the coadministration of boceprevir or telaprevir did not alter eltrombopag pharmacokinetics. Dysgeusia, headache, and somnolence occurred in ≥2 subjects. One subject withdrew because of nausea, headache, dizziness, sinus pressure, and vomiting. There were no severe or serious adverse events. Dose adjustment is not required when eltrombopag is coadministered with boceprevir or telaprevir given the lack of clinically significant pharmacokinetic interaction.

Introduction The efficacy of nebulized sodium nitrite (AIR001) has been demonstrated in animal models of pulmonary arterial hypertension (PAH), but it was not known if inhaled nitrite would be well tolerated in human subjects at exposure levels associated with efficacy in these models. Methods Inhaled nebulized sodium nitrite was assessed in three independent studies in a total of 82 healthy male and female subjects. Study objectives included determination of the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) under normal and mildly hypoxic conditions, and following co-administration with steady-state sildenafil, assessment of nitrite pharmacokinetics, and evaluation of the fraction exhaled nitric oxide (FENO) and concentrations of iron-nitrosyl hemoglobin (Hb(Fe)-NO) and S-nitrosothiols (R-SNO) as biomarkers of local and systemic NO exposure, respectively. Results Nebulized sodium nitrite was well tolerated following 6 days of every 8 h administration up to 90 mg, producing significant increases in circulating Hb(Fe)-NO, R-SNO, and FENO. Pulmonary absorption of nitrite was rapid and complete, and plasma exposure dose was proportional through the MTD dosage level of 90 mg, without accumulation following repeated inhalation. At higher dosage levels, DLTs were orthostasis (observed at 120 mg) and hypotension with tachycardia (at 176 mg), but venous methemoglobin did not exceed 3.0 % at any time in any subject. Neither the tolerability nor pharmacokinetics of nitrite was impacted by conditions of mild hypoxia, or co-administration with sildenafil, supporting the safe use of inhaled nitrite in the clinical setting of PAH. Conclusion On the basis of these results, nebulized sodium nitrite (AIR001) has been advanced into randomized trials in PAH patients. Electronic supplementary material The online version of this article (doi:10.1007/s40262-014-0201-y) contains supplementary material, which is available to authorized users.

Background Asthma is a heterogeneous disease and development of novel therapeutics requires an understanding of pathophysiologic phenotypes. The purpose of the ADEPT study was to correlate clinical features and biomarkers with molecular characteristics, by profiling asthma (NCT01274507). This report presents for the first time the study design, and characteristics of the recruited subjects. Methods Patients with a range of asthma severity and healthy non-atopic controls were enrolled. The asthmatic subjects were followed for 12 months. Assessments included history, patient questionnaires, spirometry, airway hyper-responsiveness to methacholine, fractional exhaled nitric oxide (FENO), and biomarkers measured in induced sputum, blood, and bronchoscopy samples. All subjects underwent sputum induction and 30 subjects/cohort had bronchoscopy. Results Mild (n = 52), moderate (n = 55), severe (n = 51) asthma cohorts and 30 healthy controls were enrolled from North America and Western Europe. Airflow obstruction, bronchodilator response and airways hyperresponsiveness increased with asthma severity, and severe asthma subjects had reduced forced vital capacity. Asthma control questionnaire-7 (ACQ7) scores worsened with asthma severity. In the asthmatics, mean values for all clinical and biomarker characteristics were stable over 12 months although individual variability was evident. FENO and blood eosinophils did not differ by asthma severity. Induced sputum eosinophils but not neutrophils were lower in mild compared to the moderate and severe asthma cohorts. Conclusions The ADEPT study successfully enrolled asthmatics across a spectrum of severity and non-atopic controls. Clinical characteristics were related to asthma severity and in general asthma characteristics e.g. lung function, were stable over 12 months. Use of the ADEPT data should prove useful in defining biological phenotypes to facilitate personalized therapeutic approaches. Electronic supplementary material The online version of this article (doi:10.1186/s12931-015-0299-y) contains supplementary material, which is available to authorized users.