Predictors of Phosphodiesterase Type 5 Inhibitor Treatment Failure in Patients Diagnosed With Erectile Dysfunction

INTRODUCTION

Erectile dysfunction (ED) is a prevalent condition, especially in aging populations, with significant implications for quality of life. While phosphodiesterase type 5 inhibitors (PDE5Is) are the first-line treatment, a substantial percentage of patients do not respond satisfactorily. This study aimed to identify predictors of PDE5I treatment failure in ED patients.

METHODS

Data from January 2016 to January 2022 was reviewed for patients with ED who either failed PDE5I treatment or had a successful outcome. Demographic, medical, and laboratory data were collected and analyzed. Patients with contraindications or who did not complete the treatment were excluded.

RESULTS

The treatment failure group comprised 288 patients, while 225 age-matched patients formed the control responder group. There were no significant differences in marriage duration, comorbidities, smoking, or BMI. However, HbA1c levels, free testosterone, and SHBG were significantly different between the two groups.

CONCLUSION

This study found that high HbA1c levels, low free testosterone, and high sex hormone-binding globulin (SHBG) were associated with PDE5I treatment failure. Managing high HbA1c levels and addressing hormonal imbalances may enhance PDE5I treatment effectiveness in ED patients. However, further research is needed to explore other factors contributing to treatment outcomes.

To respond or not to respond: exploring empathy-related psychological and structural brain differences between placebo analgesia responders and non-responders

Introduction

Placebo responsiveness is highly variable across individuals. In the domain of pain, it may range from pronounced hypoalgesia to no response at all. Which factors predict such variation awaits clarification, as the available literature is characterized by mixed and inconclusive results. Particularly interesting in this case are social factors such as empathy or prosocial behavior, as prior work has stressed the connection between feeling pain yourself and empathizing with pain observed in others.

Methods

In a mixed confirmatory and exploratory approach, this study investigated potential psychological and structural brain differences between placebo responders and non-responders in the domain of pain. We aggregated data of four behavioral and neuroimaging studies that had been designed to investigate the effects of placebo analgesia on empathy.

Results

Analyses comparing groups of placebo responders and non-responders showed significant group differences in trait characteristics, with responders reporting increased helping behavior and lower psychopathic traits compared to non-responders. Uncorrected results further showed higher pain-related empathic concern in responders vs. non-responders. These results were accompaniedby tentative group differences in brain structure: placebo analgesia non-responders exhibited increased gray matter volume in left inferior temporal and parietal supramarginal cortical areas, and an increased cortical surface area in bilateral middle temporal cortex.

Discussion

Together, our findings suggest that modifiability of one's pain perception by means of placebo effects is linked to personality traits characterizing social emotions and behavior. They also hint that these psychological as well as brain structural characteristics might be beneficial for the identification of placebo responders. At the same time, they stress the importance of considering contextual factors such as the study setting or paradigm when investigating the association between individual characteristics and placebo responding.

Clinical efficacy of alternative TNF inhibitor and secukinumab between primary non-responder and secondary non-responder of prior TNF inhibitor in ankylosing spondylitis

OBJECTIVES

To compare the drug retention times and clinical efficacy of alternative tumour necrosis factor inhibitors (TNFi) and secukinumab in primary and secondary non-responders with ankylosing spondylitis (AS).

METHODS

AS patients treated with biologics and enrolled in the Korean College of Rheumatology Biologics registry were examined. Patients who did not respond to previous TNFi treatment were defined as primary and secondary non-responders. Data regarding drug discontinuation and clinical efficacy were collected after 1 year. Kaplan-Meier and Cox regression analyses were performed to compare drug survival and associated factors. Logistic regression analyses were conducted to compare the clinical efficacy secukinumab with that of alternative TNFi.

RESULTS

In total, 124 patients (83 receiving alternative TNFi and 41 receiving secukinumab) had biologic changes due to clinical inefficacy. Drug retention rates in the alternative TNFi and secukinumab groups were similar (P = 0.096). However, subgroup analyses including only secondary non-responders revealed that secukinumab users showed a higher hazard ratio (HR) for drug discontinuation (HR = 3.77, P = 0.045). In addition, secukinumab was negatively associated with achieving BASDAI50 or a major improvement in the ASDAS.

CONCLUSION

Alternative TNFi showed better drug retention and clinical efficacy in AS patients experiencing previous TNFi failure, in secondary non-responders. Therefore, alternative TNFi may be a more suitable treatment for secondary non-responders.

Prevalence of healthcare workers fully vaccinated against hepatitis B without circulating antibodies in Italy and role of age at baseline cycle vaccination: a systematic review and meta-analysis

INTRODUCTION

Healthcare workers (HCWs) susceptible to hepatitis B represent an important public health concern. National and international guidelines recommend assessing the hepatitis B immune status of all HCWs and possibly vaccinating those found to be seronegative (non-responders). We conducted a meta-analysis to estimate the rate of hepatitis B sero-susceptibility among HCWs in Italy and to explore possible options for the management of non-responders.

AREAS COVERED

Nineteen studies, selected from scientific articles available in the Scopus, MEDLINE/PubMed and ISI Web of Knowledge databases between 1 January 2016 and 22 April 2022, were included. The prevalence of HBV-susceptible HCWs was 27.1% (95%CI = 23.2-31.7%). In a comparison by sex (males vs. females) the RR was 1.16 (95%CI = 1.03-1.31), and by full-cycle vaccination period (adolescence vs. infancy) the RR was 0.30 (95%CI = 0.25-0.37). Occupational health screenings for hepatitis B, with subsequent vaccination of non-responders, and exclusion of susceptible HCWs from high-risk settings have been common management strategies.

EXPERT OPINION

It is highly probable that a proportion of the next generation of medical students and HCWs will not show circulating IgG on serologic evaluation. Therefore, more targeted efforts are needed to identify these individuals and actively immunize them.

Methylglyoxal reduces molecular responsiveness to 4 weeks of endurance exercise in mouse plantaris muscle

Endurance exercise triggers skeletal muscle adaptations, including enhanced insulin signaling, glucose metabolism, and mitochondrial biogenesis. However, exercise-induced skeletal muscle adaptations may not occur in some cases, a condition known as exercise-resistance. Methylglyoxal (MG) is a highly reactive dicarbonyl metabolite and has detrimental effects on the body such as causing diabetic complications, mitochondrial dysfunction, and inflammation. This study aimed to clarify the effect of methylglyoxal on skeletal muscle molecular adaptations following endurance exercise. Mice were randomly divided into 4 groups (n = 12 per group): sedentary control group, voluntary exercise group, MG-treated group, and MG-treated with voluntary exercise group. Mice in the voluntary exercise group were housed in a cage with a running wheel, while mice in the MG-treated groups received drinking water containing 1% MG. Four weeks of voluntary exercise induced several molecular adaptations in the plantaris muscle, including increased expression of peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α), mitochondria complex proteins, toll-like receptor 4 (TLR4), 72-kDa heat shock protein (HSP72), hexokinase II, and glyoxalase 1; this also enhanced insulin-stimulated Akt Ser⁴⁷³ phosphorylation and citrate synthase activity. However, these adaptations were suppressed with MG treatment. In the soleus muscle, the exercise-induced increases in the expression of TLR4, HSP72, and advanced glycation end products receptor 1 were inhibited with MG treatment. These findings suggest that MG is a factor that inhibits endurance exercise-induced molecular responses including mitochondrial adaptations, insulin signaling activation, and the upregulation of several proteins related to mitochondrial biogenesis, glucose handling, and glycation in primarily fast-twitch skeletal muscle.

Complementary effects on glycaemic and non-glycaemic parameters between responders and non-responders treated with pioglitazone and canagliflozin in drug-naive subjects with type 2 diabetes

OBJECTIVES

The aim of this study was to investigate the differential regulation of metabolic parameters between pioglitazone and canagliflozin in relation to their glycaemic efficacies.

METHODS

Drug-naive subjects with T2DM received pioglitazone 15-30 mg/day or canagliflozin 50-100 mg/day monotherapy for 3 months. Those who had a ≥1% reduction in HbA1c were defined as responders and others who had a <1% reduction were defined as non-responders.

RESULTS

In the pioglitazone group, baseline BMI, FFA, HOMA-R or adipo-IR was significantly higher, and HDL-C was significantly lower in responders vs non-responders. In the canagliflozin group, baseline HbA1c or FBG was significantly higher, and HOMA-B or age was significantly lower in responders vs non-responders. In pioglitazone responders, significant decreases in HbA1c (from 10.75% to 8.31%), FBG (-29.7%), FFA (-37.7%), non-HDL-C (-13.4%), TG (-30.1%), HOMA-R (-35.6%) or adipo-IR (-38.7%), and increases in BMI (2.8%) or HDL-C (14.2%) were observed. In pioglitazone non-responders, none of the parameters were regulated. In canagliflozin responders, significant decreases in HbA1c (from 11.31% to 8.60%), FBG (32.1%), BMI (-2%) or HOMA-R (-33.8%), and increases in HOMA-B (50%) were observed. In canagliflozin non-responders, significant decreases in BMI (-2.4%), insulin (-21.8%) or HOMA-R (-33.6%) were observed.

CONCLUSIONS

(i) Glycaemic efficacy of pioglitazone is linked to body weight and atherogenic lipids while this is not the case with canagliflozin. (ii) Responders (or non-responders) to pioglitazone have some distinct features from non-responders (or responders) to canagliflozin. Collectively, a combination of pioglitazone and canagliflozin may compensate for each other's metabolic drawbacks or augment their advantages, thereby achieving overall improvements in the metabolic profiles and pathogenic defects of patients with T2DM.

A genome-wide association study identifying SVEP1 variant as a predictor of response to tolvaptan for cirrhotic ascites

BACKGROUND & AIMS

Tolvaptan, vasopressin V2-receptor antagonist, has been used for patients with difficult-to-treat ascites in Japan. In this study, we conducted a genome-wide association study (GWAS) in the Japanese population to identify genetic variants associated with tolvaptan's efficacy for patients with hepatic ascites.

METHODS

From 2014 through 2018, genomic DNA samples were obtained from 550 patients who were treated with tolvaptan. Of those, 80 cases (non-responder; increase of body weight [BW]) and 333 controls (responder; >1.5 kg decrease of BW) were included in the GWAS and replication study.

RESULTS

Genome-wide association study showed 5 candidate SNPs around the miR818, KIAA1109, and SVEP1 genes. After validation and performing a replication study, an SNP (rs2991364) located in the SVEP1 gene was found to have a significant genome-wide association (OR = 3.55, P = 2.01 × 10^-8 ). Multivariate analyses showed that serum sodium (Na), blood urea nitrogen (BUN) and SVEP1 SNP were significantly associated with the response (OR = 0.92, P = .003; OR = 1.02, P = .02 and OR = 3.98, P = .000008, respectively). Based on a prediction model of logistic regression analysis in a population with the rs2991364 risk allele, the failure probability (=exp (score: 22.234 + BUN*0.077 + Na*-0.179) (1 + exp (score)) was determined for the detection of non-responders. Assuming a cutoff of failure probability at 38.6%, sensitivity was 84.4%, specificity was 70% and AUC was 0.774.

CONCLUSION

SVEP1 rs2991364 was identified as the specific SNP for the tolvaptan response. The prediction score (>38.6%) can identify tolvaptan non-responders and help to avoid a lengthy period of futile treatment.

Immunogenicity and safety of HBAI20 Hepatitis B vaccine in non-responders: Double-blinded, randomised, controlled phase 2 trial

BACKGROUND & AIMS

Approximately 5%-10% of the general population respond inadequately to licensed recombinant hepatitis B vaccines. We assessed the immunogenicity and safety of a new HBAI20 vaccine, consisting of a new AI20 adjuvant (20-µg recombinant human IL-2 attached to 20-µg aluminium hydroxide) in combination with HBVaxPro®-10 µg.

METHODS

In a double-blinded, randomised, controlled phase 2 trial, 18- to 59-year-old healthy non-responders (titre <10 mIU/ml after three or more doses of hepatitis B vaccine) were assigned (3:1 ratio) to receive either HBAI20 vaccine or HBVaxPro®-10 µg in a 0, 1 and 2-month schedule. The primary outcome was seroprotection (titre ≥ 10 mIU/ml) measured 1-3 months following the third vaccination.

RESULTS

A total of 133 participants were randomised to receive either HBAI20 vaccine (n = 101) or HBVaxPro®-10 µg (n = 32). In the modified intention-to-treat analysis, the seroprotection rate after the third vaccination was 92.0% (80/87) in the HBAI20 group and 79.3% (23/29) in the HBVaxPro®-10-µg group, P = .068. Using a generalised linear mixed model to adjust for stratification factors, a higher odds of seroprotection with HBAI20 vaccine was shown (adjusted odds ratio = 3.48, P = .028). Frequency of mild and moderate local adverse events was greater in the HBAI20 group than in the HBVaxPro®-10 µg. Rates of severe local adverse events and systemic adverse events were low and similar in both groups.

CONCLUSIONS

In this group of hepatitis B vaccine non-responders, the HBAI20 vaccine demonstrated a higher seroprotection rate when adjusting for stratification factors and a similar safety profile compared to the licensed recombinant HBVaxPro®-10 µg.

Immune persistence induced by three doses of 60 μg hepatitis B vaccine in non-responders following standard primary vaccination in Chinese adults

This study consisted of two rounds of cross-sectional observations designed to evaluate the persistence of immune protection induced high antigen content hepatitis B (HB) vaccine at 60 μg/1.0 ml formulations administered at a three-dose schedule (Days 0, 28, and 56) in non-responders to routine HB vaccination. In the original phase 3 study, we enrolled 1091 healthy participants (16-60 years old) seronegative for antibody against HB surface antigen (anti-HBs) after primary vaccination. Participants were randomized (2:2:1) to receive three booster doses of HB vaccine containing 60 μg, 30 μg, or 10 μg of antigen per dose 28 days apart. In the group receiving the 60 μg HB vaccine, 428 participants' serum samples were available at pre-vaccination and 28 days after each vaccine dose and were included in immunogenicity analysis. With two written informed consents, we collected blood samples from 276 (67.2%) participants in 2014 and 239 (58.2%) in 2019, who had completed the full course of revaccination and reached the seropositive (anti-HBs≥10 mIU/ml) standard in the 60 μg vaccine group of the original phase 3 study. The HBV seropositive rate was found to decrease from 96.0% in 28 days after receiving the third dose of 60 μg HB vaccine, to 48.2% in 2014, and to 40.6% in 2019, with anti-HBs GMC of seropositive individuals was 584.0 mIU/ml, 142.4 mIU/ml, and 169.1 mIU/ml, respectively. Analysis of 181 vaccinees who had serologic test results available both in 2014 and in 2019, and results revealed a dynamic trend in anti-HBs titer similar to that for the whole immune persistence cohort. Of paramount importance, the serologic test results found that 24.9% (45/181) participants had higher anti-HBs concentrations in 2019 than in 2014, this could be interpreted as natural boosters, secondary to HBV exposure without infection because protected. In conclusion, protective antibody persists about 11 years after immunization of Chinese non-responders with 3 doses of 60 μg HB vaccine. Booster doses of vaccine do not seem necessary to ensure long-term protection.

Increased Duration of Exercise Decreases Rate of Nonresponse to Exercise but May Not Decrease Risk for Cancer Mortality

INTRODUCTION

Previous studies have observed an inverse relationship between exercise and breast cancer risk. However, there is interindividual variability in response to exercise training interventions. We investigated whether increasing the dose of aerobic exercise (150 or 300 min·wk-1), while keeping intensity of exercise constant (70%-80% HRmax), decreases the number of exercise nonresponders and further decreases associated risk for cancer mortality in our study population of women genetically predisposed for breast cancer.

METHODS

Healthy premenopausal women at elevated risk of breast cancer were randomized into control (<75 min·wk-1, n = 47), low-dose exercise (150 min·wk-1, n = 39), and high-dose exercise groups (300 min·wk-1, n = 39) for approximately 6 months. We assessed 1) clinical effectiveness (CE), defined as an improvement in predicted V˙O2max of ≥1 mL·kg-1·min-1, and twice the typical error (2× TE) of V˙O2max as thresholds to classify exercise "nonresponders"; 2) CE and 2× TE relative to exercise adherence levels; and 3) related changes in V˙O2max to predicted cancer mortality risk.

RESULTS

After our 6-month intervention, we observed that 23.5% of women in the low-dose group and 5.6% of women in the high-dose group were clinical nonresponders (P = 0.04). Clinical nonresponder status was independent of adherence level. Associated reduction in risk for cancer mortality was observed among 87.2% of women in the low-dose group and 94.9% in the high-dose group (P = 0.43).

CONCLUSION

Increasing volume (not intensity) of exercise via time spent exercising significantly decreases the number of "nonresponders." True nonresponders were observed as some women did not improve their fitness capacity despite high exercise adherence levels. Lastly, it appears 150 min·wk-1 is sufficient to decrease the predicted risk of cancer mortality.

Evaluation of a New Spike (S)-Protein-Based Commercial Immunoassay for the Detection of Anti-SARS-CoV-2 IgG

Background: The investigation of the antibody response to SARS-CoV-2 represents a key aspect in facing the COVID-19 pandemic. In the present study, we compared the new Immundiagnostik IDK® anti-SARS-CoV-2 S1 IgG assay with four widely-used commercial serological assays for the detection of antibodies targeting S (spike) and NC (nucleocapsid) proteins. Methods: Serum samples were taken from an unbiased group of convalescent patients and from a negative control group. Sample were simultaneously analyzed by the new Immundiagnostik IDK® anti-SARS-CoV-2 S1 IgG assay, by the DiaSorin LIAISON® SARS-CoV-2 S1/S2 IgG assay, and by the Euroimmun anti-SARS-CoV-2 S1 IgG ELISA. Antibodies binding NC were detected by the Abbott SARS-CoV-2 IgG assay and by the pan-immunoglobulin immunoassay Roche Elecsys® anti-SARS-CoV-2. Moreover, we investigated samples of a group of COVID-19 convalescent subjects that were primarily tested S1 IgG non-reactive. Samples were also tested by live virus and pseudovirus neutralization tests. Results: Overall, the IDK® anti-SARS-CoV-2 S1 IgG assay showed the highest sensitivity among the evaluated spike (S) protein-based assays. Additionally, the Immundiagnostik assay correlated well with serum-neutralizing activity. Conclusions: The novel IDK® anti-SARS-CoV-2 S1 IgG assay showed high sensitivity and specificity, representing a valid option for use in the routine diagnostic.

Role of the IL23/IL17 Pathway in Crohn's Disease

Crohn's disease (CD) is a chronic relapsing disorder of the gastrointestinal tract and represents one of the main entities of inflammatory bowel disease (IBD). CD affects genetically susceptible patients that are influenced by environmental factors and the intestinal microbiome, which results in excessive activation of the mucosal immune system and aberrant cytokine responses. Various studies have implicated the pro-inflammatory cytokines IL17 and IL23 in the pathogenesis of CD. IL23 is a member of the IL12 family of cytokines and is able to enhance and affect the expansion of pathogenic T helper type 17 (Th17) cells through various mechanisms, including maintenance of Th17 signature genes, upregulation of effector genes or suppression of repressive factors. Moreover, IL17 and IL23 signaling is able to induce a cascade of pro-inflammatory molecules like TNF, IFNγ, IL22, lymphotoxin, IL1β and lipopolysaccharide (LPS). Here, IL17A and TNF are known to mediate signaling synergistically to drive expression of inflammatory genes. Recent advances in understanding the immunopathogenetic mechanisms underlying CD have led to the development of new biological therapies that selectively intervene and inhibit inflammatory processes caused by pro-inflammatory mediators like IL17 and IL23. Recently published data demonstrate that treatment with selective IL23 inhibitors lead to markedly high response rates in the cohort of CD patients that failed previous anti-TNF therapy. Macrophages are considered as a main source of IL23 in the intestine and are supposed to play a key role in the molecular crosstalk with T cell subsets and innate lymphoid cells in the gut. The following review focuses on mechanisms, pathways and specific therapies in Crohn's disease underlying the IL23/IL17 pathway.

Asphyxia and Neonatal Respiratory Distress Syndrome Are Independent Predictors of the Non-response to Inhaled Nitric Oxide in the Newborns With PPHN

Aim: Not all the neonates respond with improvement in oxygenation following inhaled nitric oxide treatment (iNO) treatment. The aim of this study was to assess the independent risk factors associated with non-response to iNO during the 2 weeks of postnatal treatment in neonates diagnosed with persistent pulmonary hypertension (PPHN). Materials and Methods: This retrospective cohort study included all newborns with PPHN who received iNO treatment for more than 24 h. Demographic, obstetric, perinatal data and clinical complications were extracted from the hospitalization records. Subjects were divided into two groups according to their response to iNO inspiration during the first 24 h of iNO treatment. No response was defined as an increase in SpO₂ < 5% or the inability to sustain saturation levels in the first 24 h of iNO treatment. For descriptive statistics, χ² and t-test analysis were used to compare categorical and continuous variables between the two groups. To evaluate independent risk factors of non-responsiveness to iNO treatment, binary logistic regression analysis were performed. Results: A total of 75 newborns were included in the study. Sixty-two cases were in the responders group, and 13 cases were in the non-responders group. Univariate analysis showed that asphyxia, neonatal respiratory distress syndrome (NRDS), pulmonary surfactant administration, meconium aspiration syndrome (MAS), the severity of pulmonary hypertension (PH), and high-frequency oscillatory ventilation (HFOV) therapy were the high-risk factors affecting the response to iNO treatment in the newborns with PPHN. The binary logistic regression analysis indicated that asphyxia and NRDS incidence were independent predictors of non-responsiveness to iNO treatment [asphyxia: OR 4.193, 95% CI 1.104-15.927, P = 0.035; NRDS: OR 0.154, 95% CI 0.036-0.647, P = 0.011]. The patients in the non-responders group had shorter iNO inspiration followed by MV duration, supplemental oxygen and hospital stay, and higher mortality. There were no significant differences in IVH, PVL, and BPD between two groups. Conclusion: In the newborns with PPHN, asphyxia and NRDS resulted as the independent risk factors of non-responsiveness to iNO therapy. Asphyxia in the newborns with PPHN is detrimental to the response to iNO treatment, while NRDS is beneficial.

Response heterogeneity to lifestyle intervention among Latino adolescents

OBJECTIVE

To characterize the heterogeneity in response to lifestyle intervention among Latino adolescents with obesity.

METHODS

We conducted secondary data analysis of 90 Latino adolescents (age 15.4 ± 0.9 y, female 56.7%) with obesity (BMI% 98.1 ± 1.5%) that were enrolled in a 3 month lifestyle intervention and were followed for a year. Covariance pattern mixture models identified response phenotypes defined by changes in insulin sensitivity as measured using a 2 hour oral glucose tolerance test. Baseline characteristics were compared across response phenotypes using one-way ANOVA and chi-square test.

RESULTS

Three distinct response phenotypes (PH1, PH2, PH3) were identified. PH1 exhibited the most robust response defined by the greatest increase in insulin sensitivity over time (β ± SE, linear 0.52 ± 0.17, P < .001; quadratic -0.03 ± 0.01, P = .001). PH2 showed non-significant changes, while PH3 demonstrated modest short-term increases in insulin sensitivity which were not sustained over time (linear 0.08 ± 0.03, P = .002; quadratic -0.01 ± 0.002, P = .003). At baseline, PH3 (1.1 ± 0.4) was the most insulin resistant phenotype and exhibited the highest BMI% (98.5 ± 1.1%), 2 hours glucose concentrations (144.0 ± 27.5 mg/dL), and lowest beta-cell function as estimated by the oral disposition index (4.5 ± 2.8).

CONCLUSION

Response to lifestyle intervention varies among Latino youth with obesity and suggests that precision approaches are warranted to meet the prevention needs of high risk youth.

Inter-Individual Different Responses to Continuous and Interval Training in Recreational Middle-Aged Women Runners

A crucial subject in sports is identifying the inter-individual variation in response to training, which would allow creating individualized pre-training schedules, improving runner’s performance. We aimed to analyze heterogeneity in individual responses to two half-marathon training programs differing in running volume and intensity in middle-aged recreational women. 20 women (40 ± 7 years, 61 ± 7 kg, 167 ± 6 cm, and VO₂max = 48 ± 6 mL⋅kg^–1⋅min^–1) underwent either moderate-intensity continuous (MICT) or high-intensity interval (HIIT) 12-week training. They were evaluated before and after training with maximal incremental tests in the laboratory (VO₂max) and in the field (time to exhaustion, TTE; short interval series and long run). All the women participated in the same half-marathon and their finishing times were compared with their previous times. Although the improvements in the mean finishing times were not significant, MICT elicited a greater reduction (3 min 50 s, P = 0.298), with more women (70%) improving on their previous times, than HIIT (reduction of 2 min 34 s, P = 0.197, 50% responders). Laboratory tests showed more differences in the HIIT group (P = 0.008), while both groups presented homogeneous significant (P < 0.05) increases in TTE. Both in the short interval series and in the long run, HIIT induced better individual improvements, with a greater percentage of responders compared to MICT (100% vs 50% in the short series and 78% vs 38% in the long run). In conclusion, variability in inter-individual responses was observed after both MICT and HIIT, with some participants showing improvements (responders) while others did not (non-responders) in different performance parameters, reinforcing the idea that individualized training prescription is needed to optimize performance.

A Novel and Simple Exercise Test Parameter to Assess Responsiveness to Cardiac Resynchronization Therapy

This study assessed the value of heart rate recovery index (HRRI), a new parameter of an exercise test, as the predictor of response to cardiac resynchronization therapy (CRT). Methods: Consecutive patients receiving a CRT device were followed up after implantation and every 6 months. An effort test (ET) was quantified by minimum heart rate/maximum heart rate, as well as acceleration and deceleration times. HRRI was calculated as the ratio between acceleration and deceleration time (AT/DT) and compared to outcome. We used logistic regression to assess the predictive value of HRRI for responders and non-responders to CRT. The area under the curve (AUC) was computed to distinguish between positive and negative outcomes. Results: A total of 109 patients (74 men, mean age 63.3 ± 9.8 years) were analyzed; permanent long-term fusion CRT pacing was possible in 65 patients. Patients were assigned to two groups: responders and non-responders (98/11 patients). During a mean follow-up of 36 months, 545 ETs were performed. HRRI was significantly higher in responders versus non-responders (3.16 ± 2 vs. 1.4 ± 0.5, p < 0.001). The optimal cutoff value for HRRI as a predictor of CRT response was 1.51 (area under the receiver operating characteristic (ROC) curve = 0.844). Responders had significant left-ventricular (LV) reverse remodeling (LV end-diastolic volume = 240 ± 90 mL vs. 217 ± 89 mL, p < 0.001) and higher LV ejection fraction (26 ± 5.8% vs. 35 ± 8.7%, p < 0.001). Conclusions: HRRI computation during routine ET is useful for the evaluation of responsiveness to CRT.

An insight into primary biliary cholangitis and its recent advances in treatment: semi-synthetic analogs to combat ursodeoxycholic-acid resistance

INTRODUCTION

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease which on progression causes cirrhosis; various studies also suggested that several diseases can co-exist in patients. In existing depiction of disease PBC, apart from entire use of ursodeoxycholic acid (UDCA), several patients need to step forward to liver-transplantation or death due to resistance or non-responder with UDCA monotherapy.

AREAS COVERED

To overcome this non-respondent treatment, novel bile acid semi-synthetic analogs have been identified which shows their potency against for farnesoid X receptor and transmembrane G protein-coupled receptor-5 which are identified as target for many developing analogs which have desirable pharmacokinetic profiles.

EXPERT OPINION

A range of studies suggests that adding semisynthetic analogs in therapeutic regime improves liver biochemistries in patients with suboptimal response to UDCA. Thus, the aspire of this review is to abridge and compare therapeutic value and current markets affirm of various bile acids semi-synthetic analogs which certainly are having promising effects in PBC monotherapy or in pooled treatment with UDCA for PBC.

Influence of Housing Conditions on Reliability of Immunocastration and Consequences for Growth Performance of Male Pigs

Simple Summary

Surgical castration of male piglets is societally criticized as it is painful and violates the integrity of the animals. Pork production with boars and immunocastrates are possible alternatives. Even if immunocastration is an animal-welfare-friendly alternative, its market share is low and the reliability of this technique is discussed controversially within the pork chain. Currently, the number and the reason for non-responders to vaccination are not clear. Various factors may contribute to impaired immune response including adverse and stressful housing conditions. This study, therefore, examines the influence of different housing conditions on the immune response after two Improvac^® vaccinations. To determine vaccination success, testosterone concentrations, GnRH-binding, and boar taint compounds were evaluated. Furthermore, the growth performance of male pigs was compared. The results show that immunocastration is reliable under different housing systems and prevents boar taint. Moreover, the growth performance of immunocastrates is high and even superior to that of boars and barrows after the 2nd vaccination. Accordingly, immunocastration is not only animal-welfare-friendly but also economically attractive and suitable for different housing systems.

Abstract

Immunocastration is a sustainable alternative to piglet castration but faces limited market acceptance. The phenomenon of non-responders has not to date been examined in detail, but adverse and stressful housing conditions (e.g., mixing of groups) might impair the success of vaccinations. Therefore, we evaluated the influence of housing conditions on the immune response after two Improvac^® vaccinations at an age of 12 and 22 weeks, respectively. Boars, immunocastrates and barrows (n = 48 each) were assigned to three different housing conditions (n = 36 enriched, n = 36 standard n = 72 repeated social mixing). Immune response was quantified by measuring GnRH-binding and its consequences for testosterone concentrations, development of the genital tract and boar taint. Growth performance was evaluated via average daily gain (ADG). GnRH-binding and testosterone levels revealed that immunocastration reliably suppressed testicular functions after the 2nd vaccination. Housing conditions did not modify testicular function but influenced ADG as animals under mixing grew slower than those under enriched conditions. Gonadal status had only a slight impact on ADG except in immunocastrates, which showed a temporarily higher ADG after the 2nd vaccination. The results show that immunocastration is a reliable procedure under different housing conditions and competitive in terms of growth performance.

Rate of non-response to ursodeoxycholic acid in a large real-world cohort of primary biliary cholangitis patients in Italy

Background and aim: Response to ursodeoxycholic acid (UDCA) is crucial for the prediction of primary biliary cholangitis (PBC) prognosis, and different response criteria were validated and proposed by reference centers for PBC. To date, rates of non-response to UDCA from real-world series are lacking.Methods: Hepatology/Gastroenterology centers belonging to 'Club Epatologi Ospedalieri' (CLEO) and 'Associazione Italiana Gastroenterologi Ospedalieri' (AIGO) were invited to participate in the study, and asked to extract all patients followed for PBC, without any selection or exclusion, and fill in the database provided.Results: Thirty-four centers were enrolled throughout Italy, for a total of 713 patients. None of these centers, except one, had a hepatology outpatient clinic devoted to the care of patients with autoimmune liver diseases. After excluding 79 cases of PBC/autoimmune hepatitis overlaps, 634 patients were analyzed: mean age, 64.4 ± 12.0 years; 91.2% females; F/M 10.3/1. For patients with at least 1 year of UDCA treatment (583), rates of non-response to UDCA were evaluated according to the Paris-I/-II, Toronto and GLOBE criteria, and compared with those in the original cohorts: 27% vs 39% in Paris-I cohort; 39.6% vs 52% in Paris-II; 20.1% vs 43.5% in Toronto; 15.7% vs 30% in GLOBE (age-specific cutoffs). Mean alkaline phosphatase levels on UDCA treatment, and the age-adjusted prevalence of F3/F4 fibrosis, appeared lower in this PBC population than in reference cohorts.Conclusions: A mean ∼15% better response to UDCA is observed in a real-world PBC population, probably due to migration of some of most severe/advanced cases to PBC referral centers.

Moving beyond threshold-based dichotomous classification to improve the accuracy in classifying non-responders

We examined maximal oxygen consumption responses following exercise training to demonstrate the limitations associated with threshold‐based dichotomous classification of responders and non‐responders and proposed alternative methods for classification. Specifically, we: 1) calculated individual probabilities of response, and 2) classified individuals using response confidence intervals (CI) and reference points of zero and a smallest worthwhile change of 0.5 METs. Our findings support the use of individual probabilities and individual CIs to improve the accuracy in non‐response classification.

The management of suspected or confirmed laryngopharyngeal reflux patients with recalcitrant symptoms: A contemporary review

OBJECTIVE

To summarise current knowledge about the prevalence, aetiology and management of recalcitrant laryngopharyngeal reflux (LPR) patients-those who do not respond to anti-reflux medical treatment.

METHODS

A literature search was conducted following the PRISMA guidelines to identify studies that reported success of anti-reflux medical treatment with emphasis on studies that attempted to be rigorous in defining a population of LPR patients and which subsequently explored the characteristics of non-responder patients (ie aetiology of resistance; differential diagnoses; management and treatment). Three investigators screened publications for eligibility from PubMED, Cochrane Library and Scopus and excluded studies based on predetermined criteria. Design, diagnostic method, exclusion criteria, treatment characteristics, follow-up and quality of outcome assessment were evaluated.

RESULTS

Of the 139 articles screened, 45 met the inclusion criteria. The definition of non-responder patients varied substantially from one study to another and often did not include laryngopharyngeal signs. The reported success rate of conventional therapeutic trials ranged from 17% to 87% and depended on diagnostic criteria, treatment scheme, definition of treatment failure and treatment outcomes that varied substantially between studies. The management of non-responders differed between studies with a few differential diagnoses reported. No study considered the profile of reflux (acidic, weakly acid, non-acid or mixed) or addressed personalised treatment with the addition of alginate or magaldrate, low acid diet, or other interventions that have emerging evidence of efficacy.

CONCLUSION

To date, there is no standardised management of LPR patients who do not respond to traditional treatment approached. A diagnostic and therapeutic algorithm is proposed to improve the management of these patients. Future studies will be necessary to confirm the efficacy of this algorithm through large cohort studies of non-responder LPR patients.

LEVEL OF EVIDENCE

2a.

Cluster analysis and subgrouping to investigate inter-individual variability to non-invasive brain stimulation: a systematic review

Cluster analysis and other subgrouping techniques have risen in popularity in recent years in non-invasive brain stimulation research in the attempt to investigate the issue of inter-individual variability - the issue of why some individuals respond, as traditionally expected, to non-invasive brain stimulation protocols and others do not. Cluster analysis and subgrouping techniques have been used to categorise individuals, based on their response patterns, as responder or non-responders. There is, however, a lack of consensus and consistency on the most appropriate technique to use. This systematic review aimed to provide a systematic summary of the cluster analysis and subgrouping techniques used to date and suggest recommendations moving forward. Twenty studies were included that utilised subgrouping techniques, while seven of these additionally utilised cluster analysis techniques. The results of this systematic review appear to indicate that statistical cluster analysis techniques are effective in identifying subgroups of individuals based on response patterns to non-invasive brain stimulation. This systematic review also reports a lack of consensus amongst researchers on the most effective subgrouping technique and the criteria used to determine whether an individual is categorised as a responder or a non-responder. This systematic review provides a step-by-step guide to carrying out statistical cluster analyses and subgrouping techniques to provide a framework for analysis when developing further insights into the contributing factors of inter-individual variability in response to non-invasive brain stimulation.

Sources of Inter-individual Variability in the Therapeutic Response of Blood Glucose Control to Exercise in Type 2 Diabetes: Going Beyond Exercise Dose

In the context of type 2 diabetes, inter-individual variability in the therapeutic response of blood glucose control to exercise exists to the extent that some individuals, occasionally referred to as “non-responders,” may not experience therapeutic benefit to their blood glucose control. This narrative review examines the evidence and, more importantly, identifies the sources of such inter-individual variability. In doing so, this review highlights that no randomized controlled trial of exercise has yet prospectively measured inter-individual variability in blood glucose control in individuals with prediabetes or type 2 diabetes. Of the identified sources of inter-individual variability, neither has a prospective randomized controlled trial yet quantified the impact of exercise dose, exercise frequency, exercise type, behavioral/environmental barriers, exercise-meal timing, or anti-hyperglycemic drugs on changes in blood glucose control, in individuals with prediabetes or type 2 diabetes. In addition, there is also an urgent need for prospective trials to identify molecular or physiological predictors of inter-individual variability in the changes in blood glucose control following exercise. Therefore, the narrative identifies critical science gaps that must be filled if exercise scientists are to succeed in optimizing health care policy recommendations for type 2 diabetes, so that the therapeutic benefit of exercise may be maximized for all individuals with, or at risk of, diabetes.

Significant transcriptome and cytokine changes in hepatitis B vaccine non-responders revealed by genome-wide comparative analysis

Individuals fail to elicit protective antibody after hepatitis B vaccination remain at risk for hepatitis B virus infection. Analysis of the transcriptome of peripheral blood mononuclear cells (PBMCs) is essential to elucidate the characteristics of gene expression in non-responders. In this study, we enrolled seven responders who had received three injections and seven non-responders who had six injections of hepatitis B vaccine before. All the participants were then vaccinated with a three-dose boost regimen. Microarray analysis and Luminex assay were applied to examine mRNA expression and Th1/Th2/Th9/Th17/Th22/Treg cytokine and chemokine profiles in non-responders and responders. Differentially expressed genes in PBMCs of non-responders at 5 time points, i.e. pre-vaccination, 3^rd, 7^th, 28^th day post the first dose vaccination and 7^th day post the second dose vaccination indicated a dense network trend. Compared with responders, nine coding genes (BPI, DEFA1B, DEFA4, CEACAM8, MMP8, FOLR3, LTF, TCN1 and TKTL1) were significantly up-regulated in non-responders at all 5 time points, which could probably be the characteristic genes in hepatitis B vaccine non-responsiveness. Gene ontology analysis revealed that most of the DEGs were related with immune responses. Validation results of these 9 genes using quantitative real-time polymerase chain reaction were mostly consistent with the results of microarray. Cytokine analysis demonstrated that IL-27 and CXCL12 concentrations in responders were significantly higher than non-responders on the 3^rd day after the first dose and 7^th day after the second dose of vaccination, respectively. No significant difference was observed in other cytokine and chemokine signatures between the two groups. In conclusion, our results revealed characteristic transcriptome and cytokine changes in hepatitis B vaccine non-responders after boost immunization.

Treatment of primary biliary cholangitis ursodeoxycholic acid non-responders: A systematic review

BACKGROUND

Primary biliary cholangitis (PBC), formerly known as primary biliary cirrhosis, is a chronic cholestatic liver disease characterized by an immune mediated destruction of intrahepatic bile ducts. Ursodeoxycholic acid (UDCA) has been the primary medication for the treatment of PBC, resulting in improved liver tests, resolution of symptoms and increased transplant free survival. However, not all patients respond to UDCA. The aim of this systematic review is to provide an evidence based assessment of the medications that have been studied in patients who are refractory to UDCA.

METHODS

We performed a systematic literature search on MEDLINE and the Cochrane Database of Systematic Reviews of the published literature. A total of 23 articles fulfilling our inclusion criteria were found.

RESULTS

Several studies have shown an improvement in liver biochemistries with the use of obeticholic acid in conjunction with UDCA. Fibrates, including fenofibrate and bezafibrate, have evidence supporting benefit in this population but need more robust studies to confirm these observational results. Neither obeticholic acid nor fibrates have shown to increase transplant free survival. While there may be some benefit with methotrexate, colchicine, budesonide, mycophenolate mofetil and azathioprine, these findings were not consistent and the benefits were marginal. Further investigation is needed.

CONCLUSION

In patients with PBC refractory to UDCA, obeticholic acid or a fibrate is a reasonable choice as an adjunctive treatment to UDCA. Further investigation with randomized controlled trials is needed to provide high quality evidence to formulate standardized therapies in this difficult to treat population.

In Utero Transfer of Adeno-Associated Viral Vectors Produces Long-Term Factor IX Levels in a Cynomolgus Macaque Model

The safe correction of an inherited bleeding disorder in utero prior to the onset of organ damage is highly desirable. Here, we report long-term transgene expression over more than 6 years without toxicity following a single intrauterine gene transfer (IUGT) at 0.9G using recombinant adeno-associated vector (AAV)-human factor IX (hFIX) in the non-human primate model we have previously described. Four of six treated animals monitored for around 74 months expressed hFIX at therapeutic levels (3.9%-120.0%). Long-term expression was 6-fold higher in males and with AAV8 compared to AAV5, mediated almost completely at this stage by random genome-wide hepatic proviral integrations, with no evidence of hotspots. Post-natal AAV challenge without immunosuppression was evaluated in two animals exhibiting chronic low transgene expression. The brief neutralizing immune reaction elicited had no adverse effect and, although expression was not improved at the dose administered, no clinical toxicity was observed. This long-term surveillance thus confirms the safety of late-gestation AAV-hFIX transfer and demonstrates that postnatal re-administration can be performed without immunosuppression, although it requires dose optimization for the desired expression. Nevertheless, eventual vector genotoxicity and the possibility of germline transmission will require lifelong monitoring and further evaluation of the reproductive function of treated animals.

Parents' difficulties as co-therapists in CBT among non-responding youths with anxiety disorders: Parent and therapist experiences

No increased effect has been associated with parent involvement in cognitive behavioral therapy (CBT) for youths with anxiety disorders. The purpose of this study was to explore parent and therapist experiences of CBT among non-responding youths with anxiety disorders, with a primary focus on parent involvement in therapy. Interpretative phenomenological analysis was applied to 24 sets of semi-structured interviews with families and therapists of anxiety-disordered youths who had not profited from CBT with parental inclusion. From the superordinate theme parents' difficulties acting as co-therapists, which emerged from the analyses, two master themes represented the perspectives of parents (difficulty working together with the youth and feeling unqualified, with limited resources), and two represented the perspectives of therapists (family dynamics stood in the way of progress and difficulty transferring control to parents). Parent and therapist experiences complemented each other, offering two different perspectives on parent difficulties as co-therapists. However, the two groups' views on their respective roles in therapy were in conflict. Parents wished to remain being "just the parents" and for the experts to take over, while therapists wished to act as facilitators transferring the control to parents. Clinical implications are drawn for parental involvement and enhancement of treatment outcomes for likely non-responders.

Polymorphisms in period genes and bone response to hormone therapy in postmenopausal Korean women

OBJECTIVE

In this study, we aimed to explore the association between polymorphisms in the period (PER) gene and bone response to hormone therapy (HT) in postmenopausal Korean women.

METHODS

The PER1 c.2284C > G, c.2247C > T, PER2 c.3731G > A, PER3 c.2592G > A, c.3083T > C polymorphisms, and PER3 54bp variable number of tandem repeats (VNTR) were analyzed in 509 postmenopausal Korean women who received HT. Bone mineral density (BMD) at the lumbar spine and femoral neck before and after 1 year of HT and serum levels of osteoprotegerin (OPG), soluble receptor activator of the nuclear factor-κB ligand (sRANKL) and bone turnover markers were measured after 6 months of HT.

RESULTS

The PER1 c.2884 C > G polymorphism and PER3 54bp VNTR were associated with annual percent changes in BMD of the femoral neck after 1 year of HT (p < 0.05). Changes in BMD at the femoral neck in the non-CC genotype of the PER1 c.2884C > G polymorphism and in the 4-repeat homozygote of PER3 54bp VNTR were significantly lower than those in CC genotype and non-4-repeat homozygote, respectively. The PER1 c.2884C > G polymorphism was associated with the non-response (>3% BMD loss/year after HT) of HT. The non-CC genotype of the PER1 c.2884C > G polymorphism showed a 1.92-times higher risk of non-response at the lumbar spine and/or femoral neck (p = 0.01) compared with the CC genotype. No significant changes in bone markers after 6 months of HT were noted according to the PER1 c.2884C > G polymorphism.

CONCLUSIONS

The PER1 c.2884C > G polymorphism may be associated with risk of non-response to HT in postmenopausal Korean women.

The 'Switch' study protocol: a randomised-controlled trial of switching to an alternative tumour-necrosis factor (TNF)-inhibitor drug or abatacept or rituximab in patients with rheumatoid arthritis who have failed an initial TNF-inhibitor drug

BACKGROUND

Rheumatoid Arthritis (RA) is one of the most common autoimmune diseases, affecting approximately 1% of the UK adult population. Patients suffer considerable pain, stiffness and swelling and can sustain various degrees of joint destruction, deformity, and significant functional decline. In addition, the economic burden due to hospitalisation and loss of employment is considerable, with over 50% of patients being work-disabled within 10 years of diagnosis. Despite several biologic disease modifying anti-rheumatic drugs (bDMARD) now available, there is a lack of data to guide biologic sequencing. In the UK, second-line biologic treatment is restricted to a single option, rituximab. The aim of the SWITCH trial is to establish whether an alternative-mechanism-TNF-inhibitor (TNFi) or abatacept are as effective as rituximab in patients with RA who have failed an initial TNFi drug.

METHODS/DESIGN

SWITCH is a pragmatic, phase IV, multi-centre, parallel-group design, open-label, randomised, controlled trial (RCT) comparing alternative-mechanism-TNFi and abatacept with rituximab in patients with RA who have failed an initial TNFi drug. Participants are randomised in a 1:1:1 ratio to receive alternative mechanism TNFi, (monoclonal antibodies: infliximab, adalimumab, certolizumab or golimumab or the receptor fusion protein, etanercept), abatacept or rituximab during the interventional phase (from randomisation up to week 48). Participants are subsequently followed up to a maximum of 96 weeks, which constitutes the observational phase. The primary objective is to establish whether an alternative-mechanism-TNFi or abatacept are non-inferior to rituximab in terms of disease response at 24 weeks post randomisation. The secondary objectives include the comparison of alternative-mechanism-TNFi and abatacept to rituximab in terms of disease response, quality of life, toxicity, safety and structural and bone density outcomes over a 12-month period (48 weeks) and to evaluate the cost-effectiveness of switching patients to alternative active therapies compared to current practice.

DISCUSSION

SWITCH is a well-designed trial in this therapeutic area that aims to develop a rational treatment algorithm to potentially inform personalised treatment regimens (as opposed to switching all patients to only one available (and possibly unsuccessful) therapy), which may lead to long-term improved patient outcomes and gains in population health.

TRIAL REGISTRATION

UKCRN Portfolio ID: 12343; ISRCTN89222125 ; NCT01295151.

Revaccination of non- and low- responders after a standard three dose hepatitis B vaccine schedule

BACKGROUND

Guangdong province of China is HBV high endemicity and 1.6 million neonates are administrated 5 μg yeast recombinant anti-HBV vaccine each year. But few studies are performed to evaluate the immunogenicity and revaccination effect on non- and low- responders.

METHODS

2,199 children were administered intramuscularly with 5 μg vaccine at 0, 1 and 6 mo after birth. A 3 ml blood sample was drawn from each infant 1 mo after the third dose for determination of anti-HBs level. Three additional doses (10 μg each) were given to non- and low- responders.

RESULTS

Of 1,814 subjects, 3.1% were non-responders (anti-HBs titer < 10 mIUml (-1) ) and 28.9% were low-responders (anti-HBs ≥ 10 mIUml (-1) and < 100 mIUml (-1) ). Low birth weight (LBW) was a risk factor for non- and low- responders (RR = 1.6, 95%CI = 1.2-2.0). After revaccination, of the 34 non-responders, 14.7% became low-responders and 85.3% became responders. Of the 74 low-responders, 21.6% remained at the same level and 78.4% shifted into responder category.

CONCLUSIONS

Based on the lower responding rate after the primary immunization cycle and the higher responding rate after the additional cycle, measurement of anti-HBs level should be considered for people who had been immunized with three-dose 5 μg HB vaccine in Guangdong, especially for specific populations including LBW infants, healthcare workers, and patients with immunodeficiency disorders. An amount of 10 μg vaccine should be revaccinated to any non- and low- responders to provide adequate seroprotection.

Making preventive medicine more personalized: implications for exercise-related research

OBJECTIVE

This commentary offers a discussion of the need to consider behavioral interventions such as physical exercise as integral components of personalized medicine.

METHODS

We discuss the concept of personalized medicine and review existing evidence of variability in response to exercise training.

RESULTS

We argue that increased understanding is needed regarding sources of variability in exercise responsiveness, and that such understanding should lead to more tailored, often multimodal interventions.

CONCLUSION

Studies of personalized medicine to date have primarily investigated heterogeneity in drug responsiveness; we believe it is time to begin considering preventive strategies such as exercise within a broader scope of personalized care.

Hepatitis B in health care workers: Indian scenario

Healthcare workers have a high risk of occupational exposure to many blood-borne diseases including HIV, Hepatitis B, and Hepatitis C viral infections. Of these Hepatitis B is not only the most transmissible infection, but also the only one that is preventable by vaccination. In developing countries, Hepatitis B vaccination coverage among healthcare workers is very low for various reasons, including awareness, risk assessment, and low priority given by the health managements of both government and private hospitals. Most of the hospitals lack post-exposure management strategies including the coordination among various departments for reporting, testing, and vaccination. This review, therefore, focuses on the current situation of Hepatitis B vaccine status in the healthcare workers of India, and provides updated guidelines to manage the accidental exposure to hepatitis B virus-infected biological materials in healthcare workers. The review also emphasizes on what options are available to a healthcare worker, in case of exposure and how they can respond to the standard vaccination schedules, besides the need to educate the healthcare workers about Hepatitis B infection, available vaccines, post-vaccine immune status, and post-exposure prophylaxis.

Treatment of chronic HCV infection in special populations

The mainstay of treatment of chronic hepatitis C is pegylated interferon combined with ribavirin and more than 50% of naïve patients will have viral cure with either 6 months (genotypes 2 and 3) or 12 months (genotypes 1,4, and 6) with the initial treatment. However, populations have been defined that respond less well to routine treatment including African Americans, immune suppressed populations, obese patients and cirrhotic patients. These types of patients are enriched in groups of patients who are non-responders to treatment. This article discusses viral kinetics that may impact treatment response, strategies to maximize treatment effectiveness in these populations and the treatment of non-responders in general. Early viral kinetics can be used to define response or non-response and these results can be used to modify subsequent treatment length and dose.