Mobile health technologies in an interventional hybrid study on actinic keratosis: Results from an early phase randomized controlled trial investigating the safety and efficacy of a cytosolic phospholipase A2 inhibitor gel in photodamaged skin.

Hybrid trials are a new trend in dermatological research that leverage mobile health technologies to decentralize a subset of clinical trial elements and thereby reduce the number of in-clinic visits. In a Phase I/IIa randomized controlled hybrid trial, the safety and efficacy of an anti-proliferative and anti-inflammatory drug inhibiting cytosolic phospholipase A2 (AVX001) was tested using 1%, 3% or vehicle gel in 60 patients with actinic keratosis (AK) and assessed in-clinic as well as remotely. Over the course of 12 weeks, patients were assessed in-clinic at baseline, end of treatment (EOT) and end of study (EOS), as well as 9 times remotely on a weekly to biweekly basis. Safety outcomes comprising local skin reactions (LSR; 0-5), adverse events (AE) and cosmesis, were graded in-clinic and remotely using patient-obtained smartphone photographs (PSPs) and questionnaires; efficacy was assessed in-clinic based on clinically visible clearance of AK target area of >50%. A total of 55 participants (91.7%) completed the treatment course. The average submission rate of PSPs was high (≥85%), of which 93% were of sufficient quality. No serious AE were reported and only two experienced temporary LSR >2 (scale 0-4) and cosmesis remained stable throughout the study. Based on the mild AE and LSR profile, daily application of AVX001 gel for 1 month appears safe, tolerable, and cosmetically acceptable for use in patients with AK. At EOT, AVX001 achieved a subtle treatment response with clearance of AK target area of >50% in 18% of patients. Remote and in-clinic assessments of LSRs were in high agreement, suggesting that the use of mobile health technologies in early-phase hybrid studies of AK does not compromise patient safety.

Rapid Web-Based Recruitment of Patients With Psoriasis: Multinational Cohort Study.

BACKGROUND: Wide-ranging patient recruitment not restricted to the location of the investigator will provide a better representation of the patient population in clinical studies. OBJECTIVE: Our goal was to assess the feasibility of a broad web-based recruitment strategy in an 8-week observational study of 500 study participants with psoriasis and healthy controls from locations remote from the investigator and to assess the cost associated with each participant. METHODS: A decentralized team in Denmark recruited patients with psoriasis and healthy controls using Google and Facebook advertisements and posts to Facebook groups. All individuals were screened via the internet, and patients diagnosed with psoriasis were included. Questionnaires regarding itch and sleep were completed by both groups at inclusion, week 4, and week 8. RESULTS: During a 2-week recruitment period, 12,887 unique advertisement views were registered, and 839 participants were enrolled, of which 507 completed the study (220 with psoriasis and 287 healthy controls) with a retention rate of 60.4%. Participants were recruited from 11 different countries on 4 separate continents, mainly from the United States, Canada, and the United Kingdom. The recruitment rate was 59.9 participants per day, and the conversion rate was 57.2%. Recruitment costs were US $13 per enrolled participant and US $22 per participant completing the study. CONCLUSIONS: It is feasible and rapid to recruit a large number of participants from locations different from the investigator and to retain patients in an observational study with no visits to a clinical site at low costs.

Mild-to-moderate severity of psoriasis may be assessed remotely based on photographs and self-reported extent of skin involvement.

Background: Remote monitoring was used to assess and manage skin diseases. Objective: To investigate to what extent smartphone photographs along with a self-reported body region (BR) score can be used to evaluate psoriasis severity. Methods: Psoriasis severity was assessed in the clinic using the psoriasis area and severity index and the physician's global assessment. On the same day, the patients took a photograph of a representative lesion from 4 BR (head/neck, upper limbs, trunk, and lower limbs) and completed a questionnaire about BR score. The photographs were rated by 5 dermatologists. Intraclass correlation coefficients with 95% CIs were calculated. Results: Overall, 32 were included, of which 6% had almost clear, 69% had mild, and 25% had moderate psoriasis. Perfect agreement between the self-reported and the doctors' BR score was observed for 59%, and near-perfect agreement (deviation of maximum 1 score) was 92%. The intraclass correlation coefficient between clinical and photographic psoriasis area and severity index was 0.78 (95% CI, 0.55-0.90), and for physician's global assessment, perfect agreement was 53%. Conclusions: The agreement between psoriasis severity assessed clinically and by photographs was good in a study setting. This gives the opportunity to remotely assess psoriasis severity by combining photographs with self-reported BR scores.

Exploring Decentralized Glucose and Behaviometric Monitoring of Persons with Type 2 Diabetes in the Setting of a Clinical Trial.

BACKGROUND: Clinical trials often suffer from recruitment barriers and poor adherence, which increases costs and affects trial outcomes. OBJECTIVE: To investigate the feasibility of Decentralized Clinical Trial (DCT) design elements to recruit, enroll, and engage patients with type 2 diabetes mellitus (T2DM). METHODS: Patients with T2DM were recruited through a pharmacy and online recruitment using advert on Facebook, to 3 weeks monitoring of glucose and behaviometric parameters. Subjects recruited online could either complete an informed consent conversation in the pharmacy or through live video call managed by the study app.A continuous glucose monitoring (CGM) device to collect glucose data, and a hybrid smartwatch to monitor heart rate, track activity and sleep pattern were delivered by postal service to the participants' home address. The devices were connected to a study specific app on the participant's smartphone also capturing GPS data and questionnaire answers. RESULTS: Twenty-six subjects (3 pharmacy, 23 online) with T2DM were recruited, 85% preferred online informed consent conversation. All participants were able to self-apply the CGM device, use the smartwatch, and download the app. GPS location was captured more than 100 times for each participant, and more than 90% completed all 3 questionnaires. All the participants felt safe with the informed consent process and they felt confident in participating from home. Three participants dropped-out during the study period leaving a retention rate at 87%. CONCLUSIONS: Use of DCT design elements to conduct a T2DM study is feasible regarding recruitment, data collection from various electronic devices, and participant engagement.

The Copenhagen Actinic Keratosis Study (COAKS). A decentralised clinical trial to evaluate tolerability, safety and efficacy of daily field-directed topical treatment with cytosolic phospholipase A2 inhibitor, AVX001, in participants with actinic keratosis: protocol for a randomised controlled phase I/IIa trial.

INTRODUCTION: Actinic keratosis (AK) is the most common precancerous skin condition caused by long-term UV exposure. Given the high recurrence rate of 15%-53%, identifying safe and effective treatment options is warranted. AVX001, a cytosolic phospholipase A2α (cPLA2α) enzyme inhibitor, is a novel anti-inflammatory drug for field-directed, self-administered, topical therapy of AK. METHODS AND ANALYSIS: This study is a single-centre, randomised, vehicle-controlled, double-blind, parallel-group hybrid clinical trial in adults with multiple AK lesions Olsen grade 1 or 2. The hybrid design combines decentralised participant tasks and assessments with conventional in-clinic visits. Recruitment using targeted advertising on social media and eligibility prescreening are conducted via the Studies&Me online recruitment platform. Participants (n=60) are randomly assigned to 1 of 3 treatment arms: AVX001 gel 1%, AVX001 gel 3% or vehicle gel. The trial consists of a 4-week treatment period with daily field-directed topical application of the gel and an 8-week follow-up period. Participants attend in-clinic visits at baseline, week 4 and week 12. The remote participant trial tasks include questionnaires and upload of smartphone-obtained photos of the treated skin area using a study-specific web-based app. Both remote and in-clinic assessments of safety and efficacy will be performed. The primary objective is to evaluate the local tolerability of daily application of AVX001 gel (1% or 3%) compared with vehicle gel. Secondary objectives include safety, efficacy, dose-response efficacy relationship, treatment satisfaction and cosmetic outcome. Exploratory objectives include evaluations of tolerability and efficacy assessed by dermatologists using smartphone photos uploaded by participants, comparisons of in-clinic and remote assessments and assessment of AK-related skin changes by non-invasive optical imaging. ETHICS AND DISSEMINATION: Approved by the Ethics Committee of the Capital Region of Denmark (H-21018064) and the Danish Medicines Agency (2021032485). Results will be submitted for publication in peer-reviewed scientific journals. TRIAL REGISTRATION NUMBERS: 2021-000934-32; NCT05164393.

Changes in key recruitment performance metrics from 2008-2019 in industry-sponsored phase III clinical trials registered at ClinicalTrials.gov.

BACKGROUND: Increasing costs and complexity in clinical trials requires recruitment of more narrowly defined patient populations. However, recruitment for clinical trials remains a considerable challenge. AIM: Our overall aim was to quantify recruitment performance in industry-sponsored phase III clinical trials conducted globally during 2008-2019 with primary aim to examine development of overall clinical trial measures (number of trials completed, number of participants enrolled, trial duration in months) and key recruitment metrics (recruitment rate, number of sites, number of patients enrolled per site). METHODS: The publicly available AACT database containing data on all trials registered at ClinicalTrials.gov since 2008 was used. The analysis was completed during three time periods from 2008-2019 of 4 years each. RESULTS AND CONCLUSION: Recruitment duration for industry-sponsored phase III clinical trials have increased significantly during the last 12 years from an average recruitment period of 13 months (IQR 7-23) in 2008-2011 to 18 months (IQR 11-28) in 2016-2019 (p = 0.0068). Further, phase III clinical trials have increased the number of registered sites per clinical trial by more than 30% during the last 12 years from a median number 43 sites (IQR 17-84) in 2012-2015 to 64 sites (IQR 30-118) in 2016-2019 (p = 0.025), and concurrently, the number of participants enrolled in clinical research has decreased significantly from 2012-2015 and 2016-2019 (p = 0.046). We believe that these findings indicate that recruitment for phase III clinical trials is less effective today compared to 12 years ago.

Mild to moderate atopic dermatitis severity can be reliably assessed using smartphone-photographs taken by the patient at home: A validation study.

BACKGROUND: The use of photographs to diagnose and monitor skin diseases is gaining ground. OBJECTIVES: To investigate the validity and reliability of photographic assessments of atopic dermatitis (AD) severity. METHODS: AD severity was evaluated in the clinic by two assessors using the Eczema Area and Severity Index (EASI), SCOring Atopic Dermatitis (SCORAD), and Investigator's Global Assessment (IGA). Participants photographed the lesions with their own smartphone and completed a questionnaire about the extent of eczema the same day from home. The photographs were assessed twice with an 8 weeks interval by five dermatologists experienced in photographic evaluations. Intraclass correlation coefficients (ICC) with 95% confidence interval (CI) were applied. RESULTS: Seventy-nine participants were enrolled. The ICC between clinical EASI and photographic EASI was 0.88 (95% CI 0.81-0.93), and 0.86 (0.70-0.93) between clinical SCORAD and photographic SCORAD. Perfect agreement between clinical IGA and photograph IGA was observed for 62%, with the difference between the two never deviating with more than 1 score. The inter-rater ICC for photographic EASI and photographic SCORAD, respectively, was 0.90 (0.85-0.94), and 0.96 (0.91-0.98). The intra-rater agreements between the first and second assessments varied from 0.95 to 0.98 for photographic EASI, and from 0.86 to 0.94 for photographic SCORAD. CONCLUSION: There was high agreement between mild to moderate AD severity assessed clinically and based on smartphone photographs. Further, the photographic assessments can be reproduced with high reliability.

Remote Rating of Atopic Dermatitis Severity Using Photo-Based Assessments: Proof-of-Concept and Reliability Evaluation.

BACKGROUND: Digital imaging of dermatological patients is a novel approach to remote assessment and has recently become more relevant since telehealth and remote decentralized clinical trials are gaining ground. OBJECTIVE: We aimed to investigate whether photographs taken by a smartphone are of adequate quality to allow severity assessments to be made and to explore the usefulness of an established atopic dermatitis severity assessment instrument on photograph evaluation. METHODS: During scheduled visits in a previously published study, the investigating doctor evaluated the severity of atopic dermatitis using the Scoring AD (SCORAD) index and took photographs of the most representative lesions (target lesions) with both a smartphone and a digital single-lens reflex camera (DSLR). The photographs were then assessed by 5 dermatologists using the intensity items of the SCORAD (iSCORAD), which consists of erythema, oedema/papulation, excoriations, lichenification, oozing/crusts, and dryness (scale 0-3, maximum score 18). The mean iSCORAD of the photographs was calculated and compared with in-person assessments using Pearson correlation and Bland-Altman plots. Intraclass correlation coefficients were used for interrater reliability. RESULTS: A total of 942 photographs from 95 patients were assessed. The iSCORAD based on smartphone photographs correlated strongly with the evaluations performed in person (iSCORAD: r=0.78, P<.001; objective SCORAD: r=0.81, P<.001; and total SCORAD: r=0.78, P<.001). For iSCORAD specifically, a Bland-Altman plot showed a difference in mean score of 1.31 for in-person and remote iSCORAD. In addition, the interrater agreement between the 5 rating dermatologists was 0.93 (95% CI 0.911-0.939). A total of 170 lesions were photographed, and the difference in mean scores was 1.32, 1.13, and 1.43 between in-person and remote evaluations based on photographs taken by a DSLR camera, a smartphone without flash, and a smartphone with flash, respectively. CONCLUSIONS: In terms of quality, remote atopic dermatitis severity assessments based on photographs are comparable to in-person assessments, and smartphone photos can be used to assess atopic dermatitis severity to a similar degree as photographs from a DSLR camera. Further, the variation in how the dermatologists in this study rated the iSCORAD based on the photographs was very low.

Online Patient Recruitment in Clinical Trials: Systematic Review and Meta-Analysis.

BACKGROUND: Recruitment for clinical trials continues to be a challenge, as patient recruitment is the single biggest cause of trial delays. Around 80% of trials fail to meet the initial enrollment target and timeline, and these delays can result in lost revenue of as much as US $8 million per day for drug developing companies. OBJECTIVE: This study aimed to conduct a systematic review and meta-analysis examining the effectiveness of online recruitment of participants for clinical trials compared with traditional in-clinic/offline recruitment methods. METHODS: Data on recruitment rates (the average number of patients enrolled in the study per month and per day of active recruitment) and conversion rates (the percentage of participants screened who proceed to enroll into the clinical trial), as well as study characteristics and patient demographics were collected from the included studies. Differences in online and offline recruitment rates and conversion rates were examined using random effects models. Further, a nonparametric paired Wilcoxon test was used for additional analysis on the cost-effectiveness of online patient recruitment. All data analyses were conducted in R language, and P<.05 was considered significant. RESULTS: In total, 3861 articles were screened for inclusion. Of these, 61 studies were included in the review, and 23 of these were further included in the meta-analysis. We found online recruitment to be significantly more effective with respect to the recruitment rate for active days of recruitment, where 100% (7/7) of the studies included had a better online recruitment rate compared with offline recruitment (incidence rate ratio [IRR] 4.17, P=.04). When examining the entire recruitment period in months we found that 52% (12/23) of the studies had a better online recruitment rate compared with the offline recruitment rate (IRR 1.11, P=.71). For cost-effectiveness, we found that online recruitment had a significantly lower cost per enrollee compared with offline recruitment (US $72 vs US $199, P=.04). Finally, we found that 69% (9/13) of studies had significantly better offline conversion rates compared with online conversion rates (risk ratio 0.8, P=.02). CONCLUSIONS: Targeting potential participants using online remedies is an effective approach for patient recruitment for clinical research. Online recruitment was both superior in regard to time efficiency and cost-effectiveness compared with offline recruitment. In contrast, offline recruitment outperformed online recruitment with respect to conversion rate.

Improved patient satisfaction and diagnostic accuracy in skin diseases with a Visual Clinical Decision Support System-A feasibility study with general practitioners.

Patient satisfaction is an important indicator of health care quality, and it remains an important goal for optimal treatment outcomes to reduce the level of misdiagnoses and inappropriate or absent therapeutic actions. Digital support tools for differential diagnosis to assist clinicians in reaching the correct diagnosis may be helpful, but how the use of these affect patients is not clear. The primary objective of this feasibility study was to investigate patient experience and satisfaction in a primary care setting where general practitioners (GPs) used a visual clinical decision support system (CDSS) compared with standard consultations. Secondary objectives were diagnostic accuracy and length of consultation. Thirty-one patients with a dermatologist-confirmed skin diagnosis were allocated to consult GPs that had been randomized to conduct either standard consultations (SDR, n = 21) or CDSS (n = 16) on two separate study days one week apart. All patients were diagnosed independently by multiple GPs (n = 3-8) in both the SDR and CDSS study arms. Using the CDSS, more patients felt involved in the decision making (P = 0.05). In addition, more patients were exposed to images during the consultations (P = 6.8e-27), and 83% of those that were shown images replied they felt better supported in the consultation. The use of CDSS significantly improved the diagnostic accuracy (34%, P = 0.007), and did not increase the duration of the consultation (median 10 minutes in both arms). This study shows for the first time that compared with standard GP consultations, CDSS assist the GP on skin related diagnoses and improve patient satisfaction and diagnostic accuracy without impacting the duration of the consultations. This is likely to increase correct treatment choices, patient adherence, and overall result in better healthcare outcomes.

High adherence and low dropout rate in a virtual clinical study of atopic dermatitis through weekly reward-based personalized genetic lifestyle reports.

INTRODUCTION: Clinical trials often suffer from significant recruitment barriers, poor adherence, and dropouts, which increase costs and negatively affect trial outcomes. The aim of this study was to examine whether making it virtual and reward-based would enable nationwide recruitment, identify patients with variable disease severity, achieve high adherence, and reduce dropouts. METHODS: In a siteless, virtual feasibility study, individuals with atopic dermatitis (AD) were recruited online. During the 8-week study, subjects used their smartphones weekly to photograph target AD lesions, and completed patient-oriented eczema measure (POEM) and treatment use questionnaires. In return, subjects were rewarded every week with personalized lifestyle reports based on their DNA. RESULTS: Over the course of the 11 day recruitment period, 164 (82% women and 18% men) filled in the form to participate, of which 65 fulfilled the inclusion criteria and signed the informed consent. Ten were excluded as they did not complete the mandatory study task of returning the DNA sample. 55 (91% women, 9% men) subjects returned the DNA sample and were enrolled throughout Denmark, the majority outside the Copenhagen capital region in rural areas with relatively low physician coverage. The mean age was 28.5 (SD ±9.5 years, range 18-52 years). The baseline POEM score was 14.5±5.6 (range 6-28). Based on the POEM, 7 individuals had mild, 28 had moderate, 17 had severe, and 3 had very severe eczema. The retention rate was 96% as 53 out of 55 enrolled completed the study. The adherence was very high, and more than 90% of all study tasks were completed. Follow up of 41 subjects showed that 90% would take part again or continue if the study had been longer. CONCLUSION: A virtual trial design enables recruitment with broad geographic reach and throughout the full spectrum of disease severity. Providing personalized genetic reports as a reward seems to contribute to high adherence and retention.

Preterm Birth Has Effects on Gut Colonization in Piglets Within the First 4 Weeks of Life.

OBJECTIVES: Preterm neonates have an immature gastrointestinal tract and show an altered bacterial colonization of the gut. However, it is not clear if such immature gut microbiota (GM) colonization is induced by specific delivery, diet, environment, and/or host factors related to preterm birth. Using piglets as models for infants, we hypothesized that both shortened gestational age (GA) and start of enteral feeding affect GM composition after caesarean delivery and rearing in identical environments. METHODS: Caesarean-delivered preterm and term pigs were reared in incubators and fed total parenteral nutrition (TPN) or gradually increasing early enteral feeding (EEF) for 5 days, followed by full enteral feeding with bovine milk until day 26. GM composition was determined by 16S rRNA gene-amplicon sequencing and luminal short-chain fatty acids (SCFAs) by GC-MS. RESULTS: Both GA and EEF feeding affected GM composition on day 5, but only the GA effect persisted until day 26. On day 5, Enterobacteriaceae were dominant, with Lachnospiraceae members also being abundant. Enterobacteriaceae still dominated the GM at day 26 but with higher Akkermansia relative abundance in term pigs. Colonic concentrations of acetate and propionate were higher, and formate lower in term pigs, relative to preterm pigs on day 26. CONCLUSIONS: Preterm and term piglets, born and reared in similar ways, show differences in GM colonization during the first 4 weeks of life, which may play a role for early and later gut dysfunction resulting from preterm birth.

Rapid gut growth but persistent delay in digestive function in the postnatal period of preterm pigs.

Preterm infants often tolerate full enteral nutrition a few weeks after birth but it is not known how this is related to gut maturation. Using pigs as models, we hypothesized that intestinal structure and digestive function are similar in preterm and term individuals at 3-4 wk after birth and that early enteral nutrition promotes maturation. Preterm or term cesarean-delivered pigs were fed total parenteral nutrition, or partial enteral nutrition [Enteral (Ent), 16-64 ml·kg(-1)·day(-1) of bovine colostrum] for 5 days, followed by full enteral milk feeding until day 26 The intestine was collected for histological and biochemical analyses at days 0, 5, and 26 (n = 8-12 in each of 10 treatment groups). Intestinal weight (relative to body weight) was reduced in preterm pigs at 0-5 days but ENT feeding stimulated the mucosal volume and peptidase activities. Relative to term pigs, mucosal volume remained reduced in preterm pigs until 26 days although plasma glucagon-like peptide 2 (GLP-2) and glucose-dependent insulin-trophic peptide (GIP) levels were increased. Preterm pigs also showed reduced hexose absorptive capacity and brush-border enzyme (sucrase, maltase) activities at 26 days, relative to term pigs. Intestinal structure shows a remarkable growth adaptation in the first week after preterm birth, especially with enteral nutrition, whereas some digestive functions remain immature until at least 3-4 wk. It is important to identify feeding regimens that stimulate intestinal maturation in the postnatal period of preterm infants because some intestinal functions may show long-term developmental delay.

Physical activity level is impaired and diet dependent in preterm newborn pigs.

BACKGROUND: Preterm infants show delayed development of motor function after birth. This may relate to functional immaturity of many organs, including the gut and brain. Using pigs as model for preterm infants, we hypothesized that early initiation of enteral feeding stimulates both gut growth and neonatal physical activity. METHODS: In experiment 1, preterm and term pigs were fed parenteral nutrition (PN) or PN plus bovine colostrum (BC, 16-64 ml/kg/d enterally) for 5 d. In experiment 2, preterm pigs were fed PN+BC or PN+formula for 5 d. In experiment 3, preterm pigs were fed BC, formula, or human milk (HM) for 10 d. Incubator home cage activity (HCA) was quantified by continuous camera recordings. RESULTS: Preterm birth was associated with reduced intestinal weight and HCA (experiment 1), and BC or formula supplementation increased intestinal weights and HCA (experiments 1+2). Enteral BC and HM feeding increased HCA, intestinal weights, and necrotizing enteritis resistance, relative to formula (experiment 3). CONCLUSION: Preterm pigs show decreased physical activity, and the first enteral feeds diet dependently stimulate both gut growth and physical activity. The effects may arise from maturation of digestive, metabolic, and neurological functions, including gut serotonin production, by the first enteral feeds and milk bioactive factors.

The effect of high-fat diet on the composition of the gut microbiota in cloned and non-cloned pigs of lean and obese phenotype.

The aim of this study was to investigate the effect of high-far-high-energy diet on cloned and non-cloned domestic pigs of both lean and obese phenotype and to evaluate if the lean cloned pigs had a lower inter-individual variation as compared with non-cloned pigs. The microbiota of colon and terminal ileum was investigated in cloned and non-cloned pigs that received a high-far-high-energy diet with either restricted or ad libitum access to feed, resulting in lean and obese phenotypes, respectively. The fecal microbiota of lean pigs was investigated by terminal restriction fragment length polymorphism (T-RFLP). The intestinal microbiota of lean and obese cloned and non-cloned pigs was analyzed by quantitative real time PCR and a novel high-throughput qPCR platform (Fluidigm). Principal component analysis (PCA) of the T-RFLP profiles revealed that lean cloned and non-cloned pigs had a different overall composition of their gut microbiota. The colon of lean cloned pigs contained relatively more bacteria belonging to the phylum Firmicutes and less from the phylum Bacteroidetes than obese cloned pigs as estimated by qPCR. Fluidigm qPCR results revealed differences in specific bacterial groups in the gut microbiota of both lean and obese pigs. Our results suggest that high-far-high-energy diet is associated with changes in the gut microbiota even in the absence of obesity. Overall, the cloned pigs had a different gut microbiota from that of non-cloned pigs. To our knowledge this is the first study to investigate the gut microbiota of cloned domestic pigs of lean and obese phenotype.

Changes in the gut microbiota of cloned and non-cloned control pigs during development of obesity: gut microbiota during development of obesity in cloned pigs.

BACKGROUND: Obesity induced by a high-caloric diet has previously been associated with changes in the gut microbiota in mice and in humans. In this study, pigs were cloned to minimize genetic and biological variation among the animals with the aim of developing a controlled metabolomic model suitable for a diet-intervention study. Cloning of pigs may be an attractive way to reduce genetic influences when investigating the effect of diet and obesity on different physiological sites. The aim of this study was to assess and compare the changes in the composition of the gut microbiota of cloned vs. non-cloned pigs during development of obesity by a high-fat/high-caloric diet. Furthermore, we investigated the association between diet-induced obesity and the relative abundance of the phyla Firmicutes and Bacteroidetes in the fecal-microbiota. The fecal microbiota from obese cloned (n = 5) and non-cloned control pigs (n= 6) was investigated biweekly over a period of 136 days, by terminal restriction fragment length polymorphism (T-RFLP) and quantitative real time PCR (qPCR). RESULTS: A positive correlation was observed between body-weight at endpoint and percent body-fat in cloned (r=0.9, P<0.0001) and in non-cloned control pigs (r=0.9, P<0.0001). Shannon Weaver and principal component analysis (PCA) of the terminal restriction fragments (T-RFs) revealed no differences in the bacterial composition or variability of the fecal microbiota between the cloned pigs or between cloned and non-cloned control pigs. Body-weight correlated positively with the relative abundance of Firmicutes in both cloned (r=0.37; P<0.02) and non cloned-control pigs (r=0.45; P<0.006), and negatively with the abundance of Bacteroidetes in cloned pigs (r=-0.33, P<0.04), but not in the non-cloned control pigs. CONCLUSION: The cloned pigs did not have reduced inter-individual variation as compared to non-cloned pigs in regard to their gut microbiota in neither the obese nor the lean state. Diet-induced obesity was associated with an increase in the relative abundance of Firmicutes over time. Our results suggest that cloned pigs are not a more suitable animal model for gut microbiota-obesity related studies than non-cloned pigs. This study is the first to evaluate if cloned pigs provide a better animal model than conventional pigs in diet-intervention, obesity and gut microbiota research.