Regulatory Framework for Drug Development in Rare Diseases.

Drug development is a highly regulated industry. Therapeutic options for rare diseases must meet the same high standards for the demonstration of safety and efficacy as do those for more common diseases. The approval of the Orphan Drug Act in 1983 has resulted in many more resources for preclinical research, the standardization of patient registries, and the use of real-world data, among other measures, that, along with the advances in drug development, has resulted in the approval of therapies for some of the most unusual diseases. Increased attention to the diagnosis and treatment of rare diseases has also accelerated the development of gene therapies that may offer significant amelioration and even cures for such diseases in the near future. Rare diseases disproportionately affect children, with severe and debilitating effects. Few effective treatments are available for most rare diseases. To avoid the unnecessary waste of data collected in studies of these patients, and to promote efficient drug development, there is a growing collaboration among patient communities, investigators, clinicians, sponsors, and regulatory authorities. All interested parties are working together to identify the most appropriate research questions and move quickly to make available safe and effective treatments. This article is a survey of the most commonly used regulatory remedies that have been put in place to serve as a framework for drug development in rare diseases.

First open-label, single-arm, prospective study of real-world use of FIX replacement therapy in a predominantly pediatric hemophilia B population in China.

BACKGROUND: Nonacog alfa (recombinant factor IX [FIX]) is approved in China for the control and prevention of bleeding events in patients with hemophilia B. This was the first study to assess prophylaxis and on-demand therapy with recombinant FIX replacement in a real-world setting in China. This study aimed to evaluate the safety and efficacy of nonacog alfa in Chinese patients with hemophilia B. METHODS: In this open-label, multicenter study (clinicaltrials.gov identifier NCT02336178), patients received on-demand or prophylactic treatment with intravenous nonacog alfa for approximately 6 months or 50 exposure days, whichever occurred first. The primary safety outcome was medically important events (i.e., development of FIX inhibitors, allergic reactions, and thrombotic events). Key secondary efficacy outcomes included the annualized bleeding rate for on-demand treatment and prophylaxis, response to on-demand treatment, the number of infusions per bleeding event, and the number of breakthrough bleeding events within 48 hours of prophylaxis. RESULTS: Seventy male patients (mean [standard deviation] age 7.8 [7.2] years) were enrolled (on-demand, n = 37; prophylaxis, n = 57 [24 patients were included in both groups]). Thirty-eight (54%) patients had up to 50 FIX exposure days before the study. The only medically important event was a transient low-titer FIX inhibitor (incidence 1.4%, 95% confidence interval, 0-7.7). The mean annualized bleeding rate was 26.3 for on-demand treatment and 6.5 for prophylaxis. A mean (standard deviation) of 1.5 (1.7) nonacog alfa infusions were given per bleeding episode; 78.8% of episodes resolved with 1 infusion. Response was "excellent" or "good" for 88% of the on-demand infusions. Twenty-three bleeding events (n = 11 patients) occurred within 48 hours of 2032 prophylaxis doses (1.13%). CONCLUSION: In the real-world setting, nonacog alfa is safe and effective for on-demand treatment and for prophylaxis for patients with hemophilia B in China.

Once-weekly prophylaxis regimen of nonacog alfa in patients with hemophilia B: an analysis of timing of bleeding event onset.

In a pivotal, multicenter, open-label study, 25 patients aged 12-54 years with moderately severe/severe hemophilia B received on-demand nonacog alfa (6 months; dose at investigator's discretion) followed by once-weekly prophylaxis with nonacog alfa 100 IU/kg (12 months). During prophylaxis, patients had a median spontaneous annualized bleeding rate (sABR) of 1.0 and significant reductions in ABR (P < 0.0001). This post hoc analysis examined the time of onset of spontaneous bleeding events (sBEs) and spontaneous target joint bleeding events (sTJBEs). The postdosing day (D) of onset of sBEs observed during prophylaxis and steady-state FIX activity data (FIX:C) between 144 and 196 h postdose were collected at weeks 26 and 78. Twelve patients (48%) had no sBEs; the remaining 13 (52%) had the following onset of sBEs: less than 1 D (0%), 1 to less than 2D (5%), 2 to less than 3 D (22%), 3 to less than 4 D (9%), 4 to less than 5D (22%), 5 to less than 6D (23%), 6 to less than 7D (11%), and at least 7D (8%). Reductions in sBEs and sTJBEs during on-demand versus prophylaxis treatment were experienced by all 13 patients. Target joint sABR during prophylaxis was 0 for 5/13 patients. ABR reduction ranged from 66.1% (27.2→9.2) to 97.8% (46.2→1.0); sTJBE reductions ranged from 6.2% (2.1→2.0) to 100% (from 40.1, 19.1, 3.9, 9.0, 6.1--0). During prophylaxis, 47% (8/17) of trough FIX activity samples were more than 2%. In sBE patients, ABR and number of TJBEs were reduced with once-weekly nonacog alfa. When sBEs occurred, they followed no apparent pattern for day of occurrence. Clinicaltrials.gov identifier: NCT01335061.

Safety and Efficacy of Moroctocog Alfa (AF-CC) in Chinese Patients with Hemophilia A: Results of Two Open-Label Studies.

INTRODUCTION: Moroctocog alfa albumin-free cell culture (AF-CC) increases plasma levels of factor VIII (FVIII) activity and, in China, is indicated for the control and prevention of bleeding episodes in patients with hemophilia A. This study aimed to evaluate the efficacy, safety, and recovery data of moroctocog alfa (AF-CC) in patients with hemophilia participating in two open-label studies, both conducted in China. METHODS: The authorization study (clinicaltrials.gov identifier NCT00868530) enrolled patients aged ≥6 years, previously treated with ≥1 exposure day of FVIII replacement therapy. The real-world study (clinicaltrials.gov identifier NCT02492984) enrolled patients of any age who were previously untreated or requiring surgical prophylaxis. In both studies, on-demand treatment was administered over 6 months. Key assessments included response to treatment, FVIII inhibitor development, and recovery. RESULTS: In the authorization study (N = 53; mean age, 23.2 years; severe hemophilia, 23%), response was excellent/good for 90% of infusions at 24 hours. Seven patients developed inhibitors. Mean (SD) FVIII recovery at the initial and final visits was 1.77 (0.50) and 1.67 (0.45) (IU/dL)/(IU/kg), respectively. In the real-world study (N = 85; mean age, 9.5 years; severe hemophilia, 58%), response was rated as excellent or good for most (87%) on-demand infusions and for all surgical prophylaxis patients (n = 14). Seven patients developed FVIII inhibitors. Mean (SD) FVIII recovery at the initial and final visits was 1.71 (0.50) and 1.68 (0.31) (IU/dL)/(IU/kg), respectively. No new safety signals were observed in either study. CONCLUSION: On-demand treatment and surgical prophylaxis with moroctocog alfa (AF-CC) is safe and effective for both previously treated and previously untreated Chinese patients with hemophilia A.

Effect of Renal or Hepatic Impairment on the Pharmacokinetics, Safety, and Tolerability of Intravenous Rivipansel.

Two studies evaluated the effects of renal and hepatic impairment on pharmacokinetics and safety of rivipansel (NCT02813798, NCT02871570). A single intravenous 840-mg rivipansel dose was administered to subjects with renal impairment or normal renal function in study 1005 and subjects with moderate hepatic impairment or normal hepatic function in study 1006. Plasma (both studies) and urine (study 1005) samples were collected for 96 hours postdose. All subjects in studies 1005 (n = 28) and 1006 (n = 16) completed all study procedures. Rivipansel exposure (AUCinf ) was 47%, 124%, and 437% higher and total clearance 30%, 57%, and 82% lower in the mild, moderate, and severe renal impairment groups, respectively, than in the normal renal function group. Overall rivipansel exposure was 20% lower and total clearance 31% higher in the moderate hepatic impairment group than in the normal hepatic function group. Ten treatment-emergent adverse events occurred in studies 1005 and 1006; no event was considered treatment related. As expected, clearance of rivipansel decreased with increasing renal impairment. The difference observed between rivipansel pharmacokinetics in subjects with moderate hepatic impairment and subjects with normal hepatic function was not considered clinically significant. Single doses of rivipansel were well tolerated in subjects with either renal or hepatic impairment.

Safety and Efficacy of Tigecycline to Treat Multidrug-resistant Infections in Pediatrics: An Evidence Synthesis.

BACKGROUND: The need for antimicrobial therapies effective against multidrug resistant organisms for children remains unmet. Tigecycline shows antibacterial activity across a broad spectrum of bacteria and is approved for treating complicated skin and skin-structure infections, complicated intra-abdominal infections and, in the United States, community-acquired bacterial pneumonia for adult patients. No blinded, randomized phase 3 tigecycline clinical trials on neonates or children have been completed or planned. This review aimed to provide a comprehensive synthesis of all the existing data sources, both on-label and off-label, for tigecycline use in children. METHODS: Data on tigecycline use in children were identified from published and unpublished sources including clinical trials, expanded access and compassionate use programs, databases of healthcare records and patient safety monitoring. RESULTS: Pharmacokinetic simulations predicted that tigecycline 1.2 mg/kg (maximum dose 50 mg) every 12 hours (q12h) in children 8-11 years and 50 mg q12h in children 12 to <18 years would achieve exposure similar to adults receiving 50 mg q12h. Available phase 2 pediatric clinical trial data and data from other sources demonstrated similar clinical efficacy between adult and pediatric patients treated with tigecycline. These data showed no new or unexpected safety concerns with tigecycline in children. CONCLUSIONS: Information presented here may help guide the appropriate use of tigecycline in children with multidrug resistant infections. Continued pharmacovigilance from real-world observational studies may also further refine appropriate use of tigecycline.

A single-arm, open-label study to assess the immunogenicity, safety, and efficacy of etanercept manufactured using the serum-free, high-capacity manufacturing process administered to patients with rheumatoid arthritis.

OBJECTIVE: To evaluate the immunogenicity, safety, and efficacy of etanercept (ETN) manufactured using the serum-free, high-capacity manufacturing (SFHCM) process in patients with rheumatoid arthritis (RA). METHODS: In this global, multicenter, open-label, single-arm study (NCT02378506), 187 adult patients with moderate to severe RA received ETN 50 mg once weekly for 24 weeks manufactured using the SFHCM process. Immunogenicity (presence of antidrug antibodies (ADAs) and neutralizing antibodies (NAbs)) was assessed at 12 and 24 weeks. Safety and efficacy were evaluated at 4, 12, and 24 weeks. RESULTS: Eight (4.5%) patients tested positive for ADA, and there were no NAbs detected at any time throughout the study. Ninety (48.1%) patients reported treatment-emergent adverse events (AEs), of which 27 (14.4%) reported injection-site reactions, and 43 (23.0%) reported infections. The majority of AEs were mild or moderate in severity, and the drug was well tolerated. Throughout the duration of the study (week 4 to week 24), there was a progressive increase in the American College of Rheumatology (ACR)-defined responses (ACR20: 55.9%-82.0%, ACR50: 16.1%-57.8%, and ACR70: 3.2%-26.7%) from baseline and the proportion of patients achieving low disease activity and remission, with a corresponding decrease in measures of disease activity. CONCLUSION: The immunogenicity, safety, and efficacy of ETN manufactured using the SFHCM process were similar to the current approved ETN formulation. ClinicalTrials.gov registration: NCT02378506.

The Path to Perfect Pediatric Posology - Drug Development in Pediatrics.

Reluctance to enroll pediatric subjects in clinical trials has left gaps in information about dosing, safety, and efficacy of medications. Pharmacotherapeutic information for pediatric patients may be available for only a small range of ages and may be deficient, as children respond differently as they grow and mature from prematurity to adolescence. Current regulations, however, require early planning for the participation of children in drug development, as pediatric plans must be submitted at the end of phase 1 (European Union) or the end of phase 2 (United States). These plans are extensive, outlining planned studies, subjects to be enrolled, dose and dosage form justification, planned observations, and statistical analysis as well as planned modeling, simulation, and extrapolation analyses. The extent to which efficacy information in adults can be extrapolated to children depends on how similar the disease is in adults and each of the 5 pediatric age groups. Extrapolation may not be possible for conditions that do not occur in adults, requiring a complete development plan in adults, or extrapolation may be complete because of similar pathology and response to treatment. Pharmacokinetic and safety information cannot be extrapolated and must be collected in children of all ages, unless a waiver is granted. Physiologically based pharmacokinetic modeling, optimal design, population pharmacokinetics, and scavenged samples are all examples of new methodologies being used to study pediatric therapeutics. Clinicaltrials.gov and EU Clinical Trials registry are good sources of results of pediatric trials, although sponsors are also working toward prompt publication of study results in peer-reviewed journals.

Assessment of the Effects of Age and Renal Function on Pharmacokinetics of Bazedoxifene in Postmenopausal Women.

Bazedoxifene (BZA), a chemically distinct selective estrogen receptor modulator, has demonstrated efficacy and long-term safety in phase 3 placebo-controlled studies for prevention and treatment of osteoporosis. Here, we assessed the potential effects of age and renal function on BZA pharmacokinetics in healthy postmenopausal women (aged 55-84 years; CLcr, 32-109 mL/min). This was an open-label, single-dose, parallel, nonrandomized inpatient study conducted in healthy postmenopausal women and postmenopausal women with impaired renal function. Each subject received a single oral dose of BZA in a 20-mg tablet. Twenty-six subjects were enrolled: 8 in each of 3 age groups (55-64 years, 65-74 years, ≥75 years) and 2 (aged 71 and 75 years) with mild renal impairment; all subjects received treatment and completed the study. Age-related changes in pharmacokinetics were apparent. Although the correlation was modest (R2 = 0.28), BZA CL/F decreased steadily with age, such that the oldest group (>75 years) had a mean CL/F 60% less than the youngest group (55-64 years). Over the observed range of CLcr, there was a weak positive correlation (R2 = 0.19) between BZA CL/F and CLcr.

Performing and interpreting individual pharmacokinetic profiles in patients with Hemophilia A or B: Rationale and general considerations.

OBJECTIVES: In a separate document, we have provided specific guidance on performing individual pharmacokinetic (PK) studies using limited samples in persons with hemophilia with the goal to optimize prophylaxis with clotting factor concentrates. This paper, intended for clinicians, aims to describe how to interpret and apply PK properties obtained in persons with hemophilia. METHODS: The members of the Working Party on population PK (PopPK) of the ISTH SSC Subcommittee on Factor VIII and IX and rare bleeding disorders, together with additional hemophilia and PK experts, completed a survey and ranking exercise whereby key areas of interest in the field were identified. The group had regular web conferences to refine the manuscript's scope and structure, taking into account comments from the external feedback to the earlier document. RESULTS: Many clinical decisions in hemophilia are based on some form of explicit or implicit PK assessment. Individual patient PK profiles can be analyzed through traditional or PopPK methods, with the latter providing the advantage of fewer samples needing to be collected on any prophylaxis regimen, and without the need the for a washout period. The most useful presentation of PK results for clinical decision making are a curve of the factor activity level over time, the time to achieve a certain activity level, or related parameters like half-life or exposure (AUC). Software platforms have been developed to deliver this information to clinicians at the point of care. Key characteristics of studies measuring average PK parameters were reviewed, outlining what makes a credible head-to-head comparison among different concentrates. Large data collections of PK and treatment outcomes currently ongoing will advance care in the future. CONCLUSIONS: Traditionally used to compare different concentrates, PK can support tailoring of hemophilia treatment by individual profiling, which is greatly simplified by adopting a PopPK/Bayesian method and limited sampling protocol.

Assessment of Relative Bioavailability of Moroctocog Alfa and Moroctocog Alfa (AF-CC) in Subjects With Severe Hemophilia A.

An open-label, single-dose, randomized, two-period, crossover study comparing the pharmacokinetics of factor VIII activity in plasma (FVIII:C) after administration of an albumin-free presentation of moroctocog alfa (test) and moroctocog alfa manufactured using the previous technique (reference) was conducted in 30 (25 evaluable) male subjects who had severe hemophilia A (FVIII:C < 1 IU/dL). Blood samples were collected for 48 h after administration of each dose. FVIII: C was assayed using a chromogenic substrate assay. The FVIII:C pharmacokinetic parameters were calculated using noncompartmental analysis. The presentations would be bioequivalent if the 90% confidence limits of the ratio of the geometric mean values of AUCinf and recovery fell within the interval of 80-125%. The bioequivalence criteria were met. A total of 10 treatment-related adverse events were observed in a total of nine subjects. All were mild and none was determined to be related to administration of study medication.

The Education of Prescribers for Safe and Effective Use of Medications.

The transformation of medical education, with the disappearance of sequential lectures in pharmacology, clinical pharmacology, and therapeutics, has left gaps in skills needed for new physicians and other prescribers to safely incorporate medications into clinical practice. Brinkman et al. conducted a Delphi study of European Union (EU) medical school educators and practitioners to identify core competencies needed to prescribe medications. Their findings offer directions for learned societies, such as ASCPT, to enhance pharmacology education and practice.

A Pilot Dose-Finding Study of Etanercept in Rheumatoid Arthritis.

A randomized, parallel-dose study assessed the pharmacokinetics (PK) and pharmacodynamics (PD) of etanercept in 61 patients with rheumatoid arthritis (RA) who received doses from 10 mg once-weekly to 50 mg twice-weekly for 4 weeks. Empiric application of a maximal-effect (Emax ) model to pooled steady-state concentrations (Css ) and PD markers provided half-maximal-effect concentration estimates of 567, 573, 465, 87, and 159 ng/mL for change from baseline in number of swollen joints, number of painful joints, erythrocyte sedimentation rate, interleukin-6, and matrix metalloproteinase-3, respectively. Css >∼2,000 ng/mL did not appear to offer additional benefit. It was concluded that the middle doses, 10 mg twice-weekly, 50 mg every 2 weeks, and 50 mg once-weekly, would provide Css in the target range of 500-2,000 ng/mL. The revised US Food and Drug Administration guideline for development of medicines for treatment of RA encourages a study design incorporating PK/PD assessment to inform later studies.

Thrombogenicity evaluation in 221 patients with haemophilia B treated with nonacog alfa.

: Risk for thrombotic events with factor IX replacement therapy in patients with haemophilia B remains a concern for patients, those who treat them, and regulatory agencies, based on experience with early use of prothrombin complex concentrates. The current post hoc analysis assessed the incidence of thrombotic events and changes in prothrombin fragment 1 + 2, thrombin-antithrombin complex, and D-dimer in 221 patients with haemophilia B who received nonacog alfa in clinical studies. Thrombotic event and coagulation marker data were collected from 8 interventional studies utilizing on-demand, prophylactic, and preventive regimens in patients with haemophilia B. Mean age was 25 years (min-max, 0-69), with 51 (23%) patients aged less than 12 years and 15 (7%) aged less than 2 years. None tested positive for inhibitors. Mean time on study was 60.9 ±â€Š32 weeks and mean number of exposure days was 69.3 (min-max, 1-496). Sixty-nine (31%) patients regularly received infusions that were approximately 100 IU/kg as part of a routine prophylaxis regimen, and 29 (13%) patients underwent surgical procedures. No clinical thrombotic events were reported, and no patient experienced clinically significant changes in coagulation markers between baseline and end-of-study testing. These collective data support the low thrombotic risk associated with nonacog alfa in paediatric, adult, and surgical patients with haemophilia B receiving different treatment regimens, including doses of approximately 100 IU/kg. Although careful thrombotic clinical evaluation is important, regular coagulation marker monitoring does not appear to be warranted in patients with haemophilia B.

An Open-label, Single-dose, Pharmacokinetic Study of Factor VIII Activity After Administration of Moroctocog Alfa (AF-CC) in Male Chinese Patients With Hemophilia A.

PURPOSE: Hemophilia A represents up to 80% of all hemophilia cases in China. In patients with this condition, bleeding can be prevented and controlled by administering clotting factor VIII (FVIII). Since their initial availability, recombinant FVIII products have undergone several iterations to enhance their safety. Moroctocog alfa albumin-free cell culture (AF-CC) is among the third generation of recombinant FVIII products and received regulatory approval in China in August 2012. The present study characterizes the single-dose pharmacokinetic parameters of FVIII activity (FVIII:C) after administration of moroctocog alfa (AF-CC) in male Chinese patients with hemophilia A. METHODS: This multicenter, open-label, single-dose study enrolled 13 male Chinese patients diagnosed with severe hemophilia A (FVIII:C <1%) and a history of at least 150 exposure-days to any FVIII-containing product. Eligible patients received a single dose of moroctocog alfa (AF-CC) 50 IU/kg IV within 10 minutes. Blood samples were collected within 2 hours before administration and through 72 hours after dosing. FINDINGS: Pharmacokinetic parameters were assessed based on FVIII:C and were analyzed by age groups: ages 6 to <12 years (n = 3) and ≥12 years (n = 10). The mean plasma concentration-time profile for FVIII:C activity was consistently lower in patients aged 6 to <12 years compared with those aged ≥12 years. Geometric AUC0-∞ and Cmax were approximately 57% and 28% lower in the younger patients relative to the older patients, respectively. A total of 4 adverse events occurred in 4 patients. Low-titer, transient FVIII inhibitors were observed in 2 patients and were considered serious adverse events. Neither case resulted in clinical manifestations nor required treatment. IMPLICATIONS: This is the first report of the pharmacokinetic parameters of FVIII:C after moroctocog alfa (AF-CC) in an all-Chinese population of males with hemophilia A. The pharmacokinetic profile in older patients was similar to that previously reported with recombinant FVIII products in studies with a predominantly white population; younger patients had reduced exposure to FVIII:C. The single doses of moroctocog alfa (AF-CC) were well tolerated; 2 cases of transient, low-titer FVIII inhibitor development were observed. ClinicalTrials.gov identifier: NCT02461992.

Core Entrustable Professional Activities in Clinical Pharmacology for Entering Residency: Biologics.

Biologicals are a rapidly expanding class of medications used in the treatment of many different conditions. This article reviews the common characteristics of this class and the requirements for safe and effective use in patients. Several vignettes are included to illustrate common challenges.

Correction: The impact of anti-drug antibodies on drug concentrations and clinical outcomes in rheumatoid arthritis patients treated with adalimumab, etanercept, or infliximab: Results from a multinational, real-world clinical practice, non-interventional study.

[This corrects the article DOI: 10.1371/journal.pone.0175207.].

Lack of Effect of Rivipansel on QTc Interval in Healthy Adult African American Male Subjects.

Rivipansel is a pan-selectin inhibitor in phase 3 development for the treatment of vaso-occlusive crises in patients with sickle cell disease. This single-dose, randomized, 3-period, 3-treatment (400 mg moxifloxacin open-label, 4 g rivipansel-blinded, and placebo-blinded) crossover study evaluated the effect of rivipansel on the QT/QTc interval in 48 healthy male African American subjects (age, 21-53 years; weight, 60-115 kg). Time-matched, placebo-adjusted change from baseline QT interval using Fridericia's correction method (QTcF) was determined using a repeated-measures mixed-effects model. The highest upper bound of the 2-sided 90% confidence interval (CI) for QTcF change was 3.22 milliseconds 3 hours postdose. Moxifloxacin showed the anticipated QTcF effect, indicating that the study had adequate sensitivity to detect changes in the QTcF interval. The study concluded that no QTcF effect was demonstrated with rivipansel compared with placebo, as the upper bound of the 2-sided 90%CI was less than 10 milliseconds at all times. Exposure-response modeling for rivipansel concentrations and change from baseline in QTcF data corroborated a lack of effect with rivipansel compared with placebo. Single doses of rivipansel 4 g by intravenous infusion over 20 minutes were well tolerated in this study.

The impact of anti-drug antibodies on drug concentrations and clinical outcomes in rheumatoid arthritis patients treated with adalimumab, etanercept, or infliximab: Results from a multinational, real-world clinical practice, non-interventional study.

OBJECTIVE: To assess the incidence of anti-drug antibodies (ADA) in patients with rheumatoid arthritis (RA) treated with the TNF inhibitors etanercept (ETN), adalimumab (ADL), or infliximab (IFX), and determine the potential relationship with trough drug concentration, efficacy, and patient-reported outcomes. METHODS: This multi-national, non-interventional, cross-sectional study (NCT01981473) enrolled adult patients with RA treated continuously for 6-24 months with ETN, ADL, or IFX. ADA and trough drug concentrations were measured by independent assays ≤2 days before the next scheduled dose. Efficacy measurements included Disease Activity Score 28-joint count (DAS28), low disease activity (LDA), remission, and erythrocyte sedimentation rate (ESR). Targeted medical histories of injection site/infusion reactions, serum sickness, and thromboembolic events were collected. RESULTS: Baseline demographics of the 595 patients (ETN: n = 200; ADL: n = 199; IFX: n = 196) were similar across groups. The mean duration of treatment was 14.6, 13.5, and 13.1 months for ETN, ADL, and IFX, respectively. All ETN-treated patients tested negative for ADA, whereas 31.2% and 17.4% patients treated with ADL and IFX, respectively, tested positive. In ADL- or IFX-treated patients, those with ADA had significantly lower trough drug concentrations. There were negative correlations between trough drug levels and both CRP and ESR in ADL- and IFX-treated patients. DAS28-ESR LDA and remission rates were higher in patients without ADA. The rate of targeted medical events reported was low. CONCLUSION: ADA were detected in ADL- and IFX-treated but not ETN-treated patients. Patients without ADA generally showed numerically better clinical outcomes than those with ADA. TRIAL REGISTRATION: This study was registered on www.ClinicalTrials.gov (NCT01981473).