The change over time in the prescription pattern of the first targeted drug after failure of conventional therapy in patients with rheumatoid arthritis: a 20-year real-world experience.

OBJECTIVES: To evaluate the change over time in the pattern of the first biologic/targeted synthetic drug (b/tsDMARD) prescription and baseline characteristics in patients with rheumatoid arthritis (RA) from 1999 to the present. METHODS: A retrospective data analysis from RA patients enrolled in an Italian single-center registry was conducted. The analysis was limited to all the patients who received the first b/tsDMARD between October 1999 and December 2022. Patients were stratified according to the date of b/tsDMARD initiation into 4 groups (1999-2004, 2005-2010, 2011-2016, and 2017-2022) and a comparative analysis of prescription patterns and patients' baseline characteristics was performed. RESULTS: The study population included 1206 patients. The characteristics of patients at baseline in the 4 groups were similar overall, with the exception of disease duration (12.26, 10.5, 9.7, 8.1 years, respectively; p<0.0001), mean number of conventional DMARDs used before the first b/tsDMARD (3, 2.5, 2.1, 1.4, respectively; p<0.0001), and mean clinical disease activity index (CDAI) score (30.1, 24.3, 21.8, 20.4, respectively; p<0.0001). A progressive reduction (from 95 to 43% of patients) in the prescription of first-line TNF-α inhibitors toward other mechanisms of action has been observed. The rate of patients treated with b/tsDMARDs as monotherapy progressively increased (from 18 to 26%) especially among those not receiving a TNFα inhibitor. CONCLUSIONS: The expansion of the therapeutic armamentarium has changed the management strategy of RA over time towards an earlier introduction of targeted drugs (increasingly often as monotherapy) in patients with progressive lower disease activity and a history of failure with fewer previous conventional drugs.

Effectiveness and safety of filgotinib in rheumatoid arthritis patients: data from the GISEA registry.

OBJECTIVES: The aim of this study was to evaluate the effectiveness and safety profile of filgotinib, a JAK1 preferential inhibitor, in rheumatoid arthritis (RA) patients included in Italian GISEA (Group for the Study of Early Arthritis) registry. METHODS: Data from RA patients treated with filgotinib, recorded in the GISEA registry, were analysed. Disease activity scores and patient-reported outcomes (PROs) were assessed at baseline, as well as during 12-month follow-up. A difficult-to-treat (D2T) RA patient was defined according with EULAR criteria. Retention rate of filgotinib was estimated by the Kaplan-Meier method and factors influencing drug discontinuation were estimated by Cox regression models. RESULTS: 246 RA patients (female 89%, 57.6±12.2 years old) started filgotinib, mostly as second (22%) or further (43.9%) b/tsDMARDs line of treatment. At 3 and 12 months, 18.8% and 27.5% of patients achieved Clinical Diseases Activity Index based remission and 30.1% and 37.7% obtained a visual analogue scale of pain ≤20 (all p<0.01 vs. baseline). Filgotinib survival rate was 84.5% at the 6-month and 75.8% at 12-month follow-up, and was comparable either in monotherapy or combination therapy, and irrespective of glucocorticoid intake. b/tsDMARD naive patients had the lowest hazard ratio (HR) of filgotinib discontinuation (HR 0.29, 95%CI 0.14-0.64), while D2T-RA the highest (HR 1.82, 95%CI 1.01-3.3). Eight patients (3.3%) discontinued filgotinib due to adverse events. CONCLUSIONS: In an Italian real-life setting, filgotinib is confirmed to be safe and with a good effectiveness profile both in monotherapy and without glucocorticoids.

Retrospective evaluation of patient profiling and effectiveness of apremilast in an Italian multicentric cohort of psoriatic arthritis patients.

OBJECTIVES: We aimed to evaluate the baseline characteristics, the reasons for prescription, and the effectiveness/safety profile of real-life apremilast for the treatment of psoriatic arthritis (PsA). METHODS: PsA patients treated with apremilast were retrospectively extracted from an Italian multicentric cohort. Baseline population characteristics and reasons for apremilast prescription were analysed. Clinical response was defined as the proportion of patients achieving Disease Activity in PSoriatic Arthritis (DAPSA) remission/low disease activity (LDA), minimal disease activity (MDA), and very low disease activity (VLDA). Six-month retention rate was computed by the Kaplan-Meier method, with a detailed analysis of reasons for discontinuation. Univariate and multivariate models were developed to examine predictors of clinical response and persistence. RESULTS: The study population included 131 patients mainly with oligoarticular PsA (58%), carrying at least one comorbidity (64.1%, in particular history of malignancies [25.9%] and latent tuberculosis [16.3%]) treated with apremilast as first-line targeted therapy (47.7%) or in biologics failures (52.3%). Contraindication to biologics (60.3%) and lack of poor prognostic factors (27.5%) were the most frequent reason for apremilast prescription. The 6-month retention rate was 72.1%. Inefficacy (n=7), diarrhoea (n=10), nausea (n=3), and headache (n=7) were the most frequent reasons for discontinuation. At 3 months DAPSA LDA/remission, MDA, and VLDA were observed in 40.3, 6.7, and 5.6% of patients, respectively. Female sex was a negative predictor of both retention rate and clinical response. CONCLUSIONS: In our real-life analysis apremilast was mainly used in oligoarticular PsA carrying comorbidities leading to contraindications to biologics. Effectiveness and safety profiles were consistent with clinical trials.

Prevalence of Ankylosing Spondylitis Disease Activity Score (ASDAS) inactive disease in a cohort of patients treated with TNF-alpha inhibitors.

BACKGROUND: Treat to target (T2T), aiming at inactive disease (ID), has become the recommended strategy for axial-SpA (ax-SpA). Using the Ankylosing Spondylitis Disease Activity Score (ASDAS), we assessed the prevalence of ID in ax-SpA patients treated with TNFα inhibitors (TNFi). METHODS: A multicentric, cross-sectional study was performed assessing disease activity status (BASDAI and ASDAS) of consecutive patients with ax-SpA on stable treatment with TNFi for at least six months. We analyzed differences with nonradiographic axSpA (nr-ax-SpA) and the influence of population characteristics and comorbidities in reaching ID. ID was defined as ASDAS-CRP <1.3. RESULTS: A total of 218 patients were enrolled, 165 with AS and 53 with nr-ax-SpA. ASDAS-CRP ID was reached by 89 (40.8%) patients, while 163 (74.8%) of patients achieved good disease control with BASDAI. There were no significant differences between the two diagnostic groups. Multivariate logistic regression demonstrated a negative correlation of concomitant fibromyalgia, higher BASMI and current NSAIDs with the chances of reaching ASDAS-CRP ID or BASDAI <4. CONCLUSION: T2T represents a new challenge in the management of ax-SpA, with recently introduced disease activity measures being significantly more stringent. The prevalence of ID was affected by concomitant fibromyalgia, decreased spine mobility and concomitant NSAIDs.

Prospectively-followed pregnancies in patients with inflammatory arthritis taking biological drugs: an Italian multicentre study.

OBJECTIVES: Information on new drugs does not include their possible effects on pregnancy because pregnant women are excluded from clinical trials. Although not classified as teratogenic in animals, limited data is available on biological anti-rheumatic agents and their safety in human pregnancy. The aim of the study is to evaluate the safety of biological drugs in pregnant patients with chronic arthritis. METHODS: Pregnancy outcome and maternal disease variations were prospectively followed in six Italian Rheumatology Centres. Patients exposed to biological agents during the periconceptional period or during pregnancy were included in the study. The occurrence of congenital malformations as well as the obstetric and neonatal outcomes were assessed. RESULTS: Between 1999 and 2013 we identified 79 exposed pregnancies in 67 women affected by different rheumatic diseases with peripheral chronic arthritis. At the time of the start of pregnancy, 56 patients were taking etanercept, 13 adalimumab, 3 infliximab, 2 each certolizumab-pegol and rituximab, 1 each golimumab, anakinra and abatacept. Biological treatment was stopped after a mean of 41 days since documented pregnancy. Live births were reported in 66% of pregnancies. The rate of spontaneous pregnancy loss was 20%. Only one congenital malformation was reported. CONCLUSIONS: TNF-alpha inhibitors can be considered safe in the periconception period, representing a possible therapeutic choice also in young women affected by an aggressive form of chronic arthritis and hoping for a pregnancy. Reports of exposure during 2nd/3rd trimester are still limited and suggest caution. Experience with abatacept, tocilizumab, anakinra and rituximab in pregnancy is insufficient.

Survival on treatment with second-line biologic therapy: a cohort study comparing cycling and swap strategies.

OBJECTIVE: The aim of this study was to evaluate the survival on treatment with second-line biologic therapy in RA patient non-responders to TNF inhibitors (TNFis) by comparing treatments with a second anti-TNF (cycling strategy) or with agents with a different mechanism of action (MoA; swap strategy). METHODS: RA patients treated with biologics since 1999 who stopped a first-line TNFi and started a second-line biotherapy were included in this cohort study. After adjusting for propensity scores, drug retention rates were calculated using the Kaplan-Meier method. The log-rank test was used to compare survival curves and the Cox regression model was used to compare risk for discontinuation between the two groups. RESULTS: Two hundred and one patients discontinued the first TNFi, switching to a second anti-TNF [n = 119 (59.2%)] or to abatacept [n = 26 (31.7%)], rituximab [n = 40 (48.8%)] or tocilizumab [n = 15 (18.3%)]. Drug survival was significantly higher in the swap group than in the cycling group (P < 0.0001). After adjustment for propensity scores, probability of treatment retention in the swap group was significantly higher (hazard ratio = 2.258, 95% CI 1.507, 3.385), even after stratification according to the reason for the first TNFi discontinuation (P = 0.005). No significant differences emerged when comparing the retention rates of different MoAs (P = 0.51) in the swap group. CONCLUSION: In the clinical practice setting, the best option for managing TNFi non-responders seems to be swapping to a different MoA, with no differences between abatacept, rituximab and tocilizumab, irrespective of the reason for first TNFi discontinuation.

Ten-year drug survival of anti-TNF agents in the treatment of inflammatory arthritides.

Tumor necrosis factor (TNF) inhibitor therapies (anti-TNFs) are used routinely as first-line biotherapy for the treatment of rheumatoid arthritis (RA) and spondyloarthritis (SpA: psoriatic arthritis [PsA] and ankylosing spondylitis [AS]) in patients who have failed traditional non-biologic disease-modifying anti-rheumatic drugs (DMARDs). However, about 30% of patients experience failure of first-line anti-TNF agent because of inefficacy or adverse events. This study analyzed long-term anti-TNFα drug survival in a clinical practice setting. The overall 10-year retention rate of first-line anti-TNF agent is about 23%, being significantly higher for SpA compared with RA patients. ETN is the most persistent anti-TNF with a drug survival rate significantly higher than IFX and ADA.

The impact of EMA recommendations on the real-life use of Janus kinases inhibitors for rheumatoid arthritis: the Expanded Risk Score in RA as a tool to quantify the risk of cardiovascular events.

Objective: To evaluate in patients with rheumatoid arthritis (RA) the impact of EMA recommendations on the real-life prescription of JAK inhibitors (JAKis) and the use of the Expanded Risk Score in RA (ERS-RA) to quantify the risk of major adverse cardiac events (MACE). Methods: We conducted a retrospective analysis of real-life RA patients treated with JAKis. Patients were classified as ineligible for JAKis if they fulfilled EMA criteria (>65 years-old, history of malignancy, or increased risk of venous thromboembolic events [VTE] or MACE including smoking). Risk of MACE was defined according to ORAL Surveillance trial inclusion criteria (ORALSURV) or by using the ERS-RA. Results: Of 194 patients enrolled, 57.9% were classified as ineligible according to EMA definition (ORALSURV criteria). The most frequent reason for ineligibility was increased MACE risk (70.2%), followed by age>65 (34.2%), smoking (30.7%), and increased risk of VTE (20.2%) or malignancy (7%). The use of the ERS-RA reduced the rate of patients carrying an increased CV risk to 18.6% (p<0.001 versus ORALSURV), leading to 46.4% overall ineligible patients. Over a drug-exposure of 337 patient/years, we observed 2 VTE, one MACE (non-fatal stroke), and one solid malignancy (all in the group of patients classified as ineligible according to both the definitions). Conclusions: Rigorous application of EMA indications in clinical practice could result in the exclusion of a large proportion of RA patients from treatment with JAKis. A proper quantification of the risk for MACE by dedicated tools as ERS-RA is advocated to better tailor the management of RA.

Corrigendum: The Impact of Anti-rheumatic Drugs on the Seroprevalence of Anti-SARS-CoV-2 Antibodies in a Cohort of Patients With Inflammatory Arthritis: The MAINSTREAM Study.

[This corrects the article DOI: 10.3389/fmed.2022.850858.].

The Impact of Anti-rheumatic Drugs on the Seroprevalence of Anti-SARS-CoV-2 Antibodies in a Cohort of Patients With Inflammatory Arthritis: The MAINSTREAM Study.

Objectives: Given the high occurrence of asymptomatic subsets, the true prevalence of SARS-CoV-2 infection in rheumatic patients is still underestimated. This study aims to evaluate the seroprevalence of SARS-CoV-2 antibodies in rheumatic musculoskeletal diseases (RMD) patients receiving immunomodulatory drugs. Methods: All consecutive patients with rheumatoid arthritis or spondyloarthritis receiving disease-modifying antirheumatic drugs (DMARDs) evaluated between 4th May and 16th June 2020 were included. All participants were tested for anti-SARS-CoV-2 antibodies (IgG, IgM, IgA) by ELISA and were questioned about previous COVID-19 symptoms and clinical course. Results were compared with healthy population from the same region and with a control group of healthy subjects diagnosed with confirmed COVID-19. Results: The study population includes 358 patients. The overall prevalence of anti-SARS-CoV-2 antibodies (18.4%) was higher than prevalence rate based on swab-positivity (1.12%) or clinically suspected cases (10.6%), but consistent with seroprevalence observed in the healthy population. Among seropositive patients 58% were asymptomatic. Mean anti-SARS-CoV-2 titer was comparable with the control group. No differences in seroprevalence were observed according to age, sex, rheumatic disease and treatment with conventional, biologic or targeted synthetic DMARDs, whereas glucocorticoids and comorbidities resulted in higher seroprevalence rate. Conclusions: The results of this study are reassuring about the low impact of RMDs and immunomodulatory therapies on the risk and clinical course of COVID-19 and on humoral immune response to SARS-CoV-2 infection.

Immunosuppressant Treatment in Rheumatic Musculoskeletal Diseases Does Not Inhibit Elicitation of Humoral Response to SARS-CoV-2 Infection and Preserves Effector Immune Cell Populations.

COVID-19 has proven to be particularly serious and life-threatening for patients presenting with pre-existing pathologies. Patients affected by rheumatic musculoskeletal disease (RMD) are likely to have impaired immune responses against SARS-CoV-2 infection due to their compromised immune system and the prolonged use of disease-modifying anti-rheumatic drugs (DMARDs), which include conventional synthetic (cs) DMARDs or biologic and targeted synthetic (b/ts) DMARDs. To provide an integrated analysis of the immune response following SARS-CoV-2 infection in RMD patients treated with different classes of DMARDs we carried out an immunological analysis of the antibody responses toward SARS-CoV-2 nucleocapsid and RBD proteins and an extensive immunophenotypic analysis of the major immune cell populations. We showed that RMD individuals under most DMARD treatments mount a sustained antibody response to the virus, with neutralizing activity. In addition, they displayed a sizable percentage of effector T and B lymphocytes. Among b-DMARDs, we found that anti-TNFα treatments are more favorable drugs to elicit humoral and cellular immune responses as compared to CTLA4-Ig and anti-IL6R inhibitors. This study provides a whole picture of the humoral and cellular immune responses in RMD patients by reassuring the use of DMARD treatments during COVID-19. The study points to TNF-α inhibitors as those DMARDs permitting elicitation of functional antibodies to SARS-CoV-2 and adaptive effector populations available to counteract possible re-infections.

Clinical management of patients with rheumatoid arthritis during the COVID-19 pandemic.

Introduction: Coronavirus disease 2019 (COVID-19) pandemic raises a great challenge in the management of patients with rheumatoid arthritis (RA), which are generally more susceptible to infection events because of the autoimmune condition itself and the treatment with immunomodulatory drugs. The use of disease-modifying anti-rheumatic drugs (DMARDs), including biologics and targeted-synthetic DMARDs, has aroused particular interest because of both their immunosuppressive effects and their hypothetical potential in COVID-19 treatment.Areas covered: For this narrative review, a literature search was conducted between December 2019 and February 2021 on PubMed including epidemiological studies, gathering the main evidence available to date about the impact of COVID-19 on RA patients and the influence of anti-rheumatic drugs on patients' susceptibility to this infection. We also summarize the recommendations from the international guidelines on the management of rheumatic diseases and treatments in this pandemic context, especially focused on RA.Expert opinion: About a year after the outbreak of the pandemic, we are able to answer some of the most relevant questions regarding patients with RA and their management in this pandemic context. Our efforts must now be directed toward consolidating the currently available data with more rigorous studies and facing new issues and challenges including, foremost, vaccination.

Clinical pharmacology of filgotinib in the treatment of rheumatoid arthritis: current insights.

INTRODUCTION: Rheumatoid arthritis (RA) is a chronic autoimmune disease, whose natural course has been deeply modified thanks to the development of new therapeutic approaches. The Janus kinase inhibitors (Jakinibs) represent the newest class of drugs introduced for treating RA. Among these, Filgotinib (FIL) has been developed as Janus kinase1 (JAK1) selective inhibitor, specifically targeting key pro-inflammatory mediators in RA pathogenesis. AREAS COVERED: This narrative review provides an overview on FIL as new therapeutic approach for RA, with focus on its pharmacological properties, clinical efficacy, and safety profile. The following electronic databases were adopted for the study search: PubMed, Google Scholar, ClinicalTrials.gov and Abstract archive from the American College of Rheumatology and the European Alliance of Associations for Rheumatology. EXPERT OPINION: The phase II and phase III randomized controlled trials (RCTs) performed so far and their long-term extensions showed a comparable clinical efficacy of FIL to biologic treatments, with an acceptable safety profile. Thanks to these data, FIL was approved in Europe and Japan for the treatment of active RA, increasing the spectrum of therapeutic approaches and improving the possibility of a more tailored therapeutic strategy. Real-life data and head-to-head clinical trials will be needed to confirm its efficacy and safety.

Mild cognitive impairment in psoriatic arthritis: Prevalence and associated factors.

ABSTRACT: To assess the prevalence and factors associated with mild cognitive impairment (MCI) in patients suffering from psoriatic arthritis (PsA).A cross-sectional evaluation was conducted in consecutive PsA patients. Sociodemographic data and the clinimetric variables related to PsA and psoriasis were collected for each patient. MCI was assessed through the Montreal Cognitive Assessment (MoCA). The cognitive performance of PsA patients was compared to healthy subjects using one-way analysis of variance (ANOVA). The correlations among variables were studied by the Spearman rank correlation coefficient. A multivariate logistic regression analysis was carried out to establish the predictors of MCI.The study involved 96 PsA patients and 48 healthy subjects. MCI (defined as a MoCA score < 26/30) was detected in 47 (48.9%) PsA patients. Compared to healthy subjects, the MoCA score resulted significantly lower in PsA patients (P = .015). The main differences involved the denomination and language domains. MoCA was negatively correlated with age (r = -0.354; P < .0001), HAQ-DI (r = -0.227; P = .026), and fatigue (r = -0.222; P = .029), and positively correlated with psoriasis duration (r = 0.316; P = .001) and DLQI (r = 0.226; P = .008).The multivariate logistic regression analysis revealed the duration of psoriasis (P = .0005), age (P = .0038), PASI (P = .0050), and HAQ-DI (P = .0193) as predictors of the MoCA score.MCI is present in a significant proportion of PsA patients, and is mainly determined by age, cutaneous variables, and disability.

Retention rate of a second line with a biologic DMARD after failure of a first-line therapy with abatacept, tocilizumab, or rituximab: results from the Italian GISEA registry.

OBJECTIVES: EULAR recommendations do not suggest which biologic disease-modifying anti-rheumatic drug (bDMARD) should be preferred after failure of a first bDMARD in the treatment of rheumatoid arthritis (RA). In particular, few data are available regarding the effectiveness of a second-line bDMARD after failure of abatacept (ABA), tocilizumab (TCZ), and rituximab (RTX). The aim of this study was to analyze the retention rate of a second line with tumor necrosis factor inhibitors (TNFi) or other mechanisms of action (MoAs), after the failure of either RTX, TCZ, or ABA. METHODS: Two hundred and seventy-eight RA patients from the Italian GISEA registry were included in the study. RTX was the first bDMARD in 18% of patients, ABA in 45.7%, and TCZ in 36.3%, while the second bDMARD was a TNFi (group 1) in 129 patients and an agent with a different MoA (group 2) in 149. RESULTS: During a median follow-up of 22 months (IQR 68), 129 patients discontinued their treatment; patients of group 1 discontinued the treatment more frequently than patients of group 2 (p<0.001) with retention rates of 33.6±5.7% and 63.6±4.6% after 104 weeks for group 1 and group 2, respectively (p<0.001). At multivariate analysis, the mechanism of action was the only predictor for the maintenance in therapy. CONCLUSIONS: According to our data, ABA, RTX, and TCZ seem to maintain a good retention rate also when used as a second-line therapy, suggesting their use after the failure of a non-TNFi as first-line therapy. However, specifically designed studies are needed to evaluate the more appropriate therapeutic strategies in RA, according to the first-line drug, including new targeted synthetic DMARDs. Key Points • A large proportion of rheumatoid arthritis patients fail the first biologic DMARD. • Few data are available about the efficacy of biologic DMARD after the failure of a non-TNF inhibitor. • Abatacept, rituximab, or tocilizumab seem to maintain a good retention rate after the failure of a first-course therapy with a non-TNF inhibitor.

Impact of corticosteroids and immunosuppressive therapies on symptomatic SARS-CoV-2 infection in a large cohort of patients with chronic inflammatory arthritis.

BACKGROUND: Prevalence and outcomes of coronavirus disease (COVID)-19 in relation to immunomodulatory medications are still unknown. The aim of the study is to investigate the impact of glucocorticoids and immunosuppressive agents on COVID-19 in a large cohort of patients with chronic immune-mediated inflammatory arthritis. METHODS: The study was conducted in the arthritis outpatient clinic at two large academic hospitals in the COVID-19 most endemic area of Northern Italy (Lombardy). We circulated a cross-sectional survey exploring the prevalence of severe acute respiratory syndrome-coronavirus-2 nasopharyngeal swab positivity and the occurrence of acute respiratory illness (fever and/or cough and/or dyspnea), administered face-to-face or by phone to consecutive patients from 25 February to 20 April 2020. COVID-19 cases were defined as confirmed or highly suspicious according to the World Health Organization criteria. The impact of medications on COVID-19 development was evaluated. RESULTS: The study population included 2050 adults with chronic inflammatory arthritis receiving glucocorticoids, conventional-synthetic (cs), or targeted-synthetic/biological (ts/b) disease-modifying drugs (DMARDs). Laboratory-confirmed COVID-19 and highly suspicious infection were recorded in 1.1% and 1.4% of the population, respectively. Treatment with glucocorticoids was independently associated with increased risk of COVID-19 (adjusted OR [95% CI] ranging from 1.23 [1.04-1.44] to 3.20 [1.97-5.18] depending on the definition used). Conversely, patients treated with ts/bDMARDs were at reduced risk (adjusted OR ranging from 0.46 [0.18-1.21] to 0.47 [0.46-0.48]). No independent effects of csDMARDs, age, sex, and comorbidities were observed. CONCLUSIONS: During the COVID-19 outbreak, treatment with immunomodulatory medications appears safe. Conversely, glucocorticoids, even at low-dose, may confer increased risk of infection. TRIAL REGISTRATION: Retrospectively registered. Not applicable.

Personalized medicine in rheumatoid arthritis: How immunogenicity impacts use of TNF inhibitors.

Up to 40% of patients treated with tumor necrosis factor alpha inhibitors (TNFi) do not respond to therapy. Testing drug bioavailability and/or anti-drug antibody (ADAb) levels may justify dosage adjustment or switch to different drugs, enabling a personalized medicine approach. We report a multicenter cross-sectional study on different methods [ELISA and a cell based functional assay (reporter gene assay - RGA)] for drug/ADAb detection, and on the relationship between drug bioavailability and ADAb. 163 patients with rheumatoid arthritis (RA) treated with infliximab (IFX; n = 67), adalimumab (ADL; n = 49) or etanercept (ETA; n = 47) were tested for drug and ADAb levels. Furthermore, we report prospective data from additional 70 patients (59 RA and 11 juvenile idiopathic arthritis - JIA) tested for drug and ADAb levels at baseline (T0) and after 3 (T3) and 6 months (T6) of treatment with ADL or ETA only. IFX-treated patients were not included because of the increasing use of IFX biosimilars. Stringent inclusion criteria were used in order to avoid unwanted variables in both studies; none of the patients used TNFi before the study, and TNFi was used only in combination with methotrexate. Clinical response was defined according to EULAR response criteria. The two assays performed comparably in the comparison study. Accordingly, ELISA was selected for the prospective study because of its feasibility in the clinical setting. The cross-sectional study found ADAb in IFX and ADL treated groups only, that were associated with a decrease in pharmacological drug availability in the blood. Comparable results were found for the ADL-treated group in the prospective study which also showed a relationship between drug/ADAb levels and the loss of clinical response. Altogether our findings support drug and anti-drug Ab monitoring in the real-world clinical setting thus enabling individualized treatment and reducing disability in chronic inflammatory arthritis.