Immune checkpoint inhibitors (ICIs) have improved survival rates in oncology, but there is a rising concern for immune-related adverse health outcomes. Monitoring drug serum concentration would enable tailored dosing, however this strategy has not yet been evaluated for ICIs. Fully automated analyte capture assays with timeresolved fluorometry using protein A as tracer, were developed for three different ICIs; the cytotoxic T lymphocyte Antigen-4 (CTLA4) inhibitor ipilimumab (Yervoy; Bristol-Myers Squibb) and the Programmed Death1 (PD-1) inhibitors nivolumab (Opdivo; Bristol-Myers Squibb) and pembrolizumab (Keytruda; Merck). Drug trough levels were measured in serum samples from ICI-treated patients. Measuring ranges were 1-100 mg/L for all three drugs. Automation allowed for 110 samples to be analyzed in <4 h. Median drug trough-levels after 5-7 weeks of treatment were 20 (range <1.0-45) mg/L for ipilimumab (n = 113), 60 (range 14-75) mg/L) for nivolumab (n = 21) and 19 (range 7.4-39) mg/L for pembrolizumab (n = 20). Routine drug concentration monitoring for ipilimumab, nivolumab and pembrolizumab is feasible using fully automated analyte capture assays constructed with commercially available reagents. The large drug serum concentration ranges in samples from real-world patients, should be further investigated to assess the clinical relevance of ICI concentration monitoring.

Background A large proportion of individuals with coeliac disease (CeD) remain undiagnosed. Objective The aim of this study was to assess serological screening for CeD in the adult general population. Design The study was based on the fourth Trøndelag Health Study, a population-based study performed 2017–2019 in Nord-Trøndelag County, Norway, including 56 042 participants >20 years of age (54% participation rate). Serum samples were analysed with a dual antitransglutaminase 2 (TG2) IgA and IgG assay and seropositive participants were invited to endoscopy with duodenal biopsies. A CeD diagnosis was given if mucosal damage (Marsh grade 3) was found. Results Histological evaluation of 657 seropositive participants confirmed CeD in 423. The positive predictive value (PPV) of a positive TG2 IgA was 73.3% (95% CI 69.7% to 77.0%) for biopsy-confirmed CeD. TG2 IgA ≥10 times the upper limit of normal (ULN), as used in the no-biopsy approach in children, increased the PPV to 88.1% (95% CI 84.8% to 91.4%). Primary TG2 IgG response was found in 87 participants, five of whom had biopsy-confirmed CeD. One of the participants with CeD primarily responding with TG2 IgG was IgA deficient. The PPV of a positive TG2 IgG was 5.8% (95% CI 1.9% to 12.9%) and of TG2 IgG ≥10× ULN was 9.5% (95% CI 1.2% to 30.4%) for biopsy-confirmed CeD in TG2 IgA-negative individuals. Conclusion The TG2 IgA assay showed excellent abilities as a screening tool for CeD in the adult general population. However, the diagnostic accuracy of TG2 IgG was too poor for selectively identifying individuals with CeD.

Objectives The objectives of this study are to identify a therapeutic serum level for adalimumab associated with remission and low disease activity in patients with rheumatoid arthritis.Methods Associations between serum adalimumab trough levels and disease activity were examined using longitudinal data from a 48-week randomised phase III trial including patients with tumour necrosis factor inhibitor-naïve rheumatoid arthritis with active disease starting adalimumab treatment. Disease activity was classified according to 28-joint Disease Activity Score (DAS28)-erythrocyte sedimentation rate and C reactive protein (CRP) levels.Results Adalimumab trough levels were recorded longitudinally for 336, 330 and 302 patients at weeks 12, 24 and 48, respectively. All patients received concomitant methotrexate. Median adalimumab trough levels were 6.4 mg/L (IQR 3.4–9.5) at week 12, 7.5 mg/L (IQR 3.5–10.9) at week 24 and 7.6 mg/L (IQR 3.6–12.0) at week 48. In serial serum samples from weeks 12, 24 and 48, trough levels ≥3.9 mg/L were associated with DAS28 remission (OR 3.88 (95% CI 1.80, 8.38), p<0.001) and lower CRP levels (p<0.001). Week 12 trough levels ≥3.5 mg/L were associated with DAS28 low disease activity at week 24 (OR 2.62 (1.50, 4.56), p<0.001) and remission at week 48 (OR 1.99 (1.02, 3.88), p=0.04), as well as lower CRP levels at both time points (p<0.001).Conclusion Adalimumab trough levels above 4.0 mg/L were associated with remission/low disease activity throughout the first year of adalimumab therapy and can be considered a lower target level for therapeutic drug monitoring of adalimumab therapy.

Objectives: To explore associations between serum adalimumab level, treatment response and drug survival in order to identify optimal drug levels for therapeutic drug monitoring of adalimumab. Also, to assess the occurrence and risk factors of anti-drug antibody (ADAb) formation. Methods: Non-trough adalimumab and ADAb levels were measured by automated fluorescence assays in serum collected after 3 months of adalimumab treatment in patients with RA, PsA or axial SpA (axSpA) included in the observational NOR-DMARD study. Treatment response was evaluated after 3 months and drug survival was evaluated during long-term follow-up. Results: In 340 patients (97 RA, 69 PsA, 174 axSpA), the median adalimumab level was 7.3 mg/l (interquartile range 4.0-10.3). A total of 33 (10%) patients developed ADAbs. Findings were comparable across diagnoses. In RA and PsA, adalimumab levels >= 6.0 mg/l were associated with treatment response [odds ratio (OR) 2.2 (95% CI 1.0, 4.4)] and improved drug survival [hazard ratio 0.49 (95% CI 0.27, 0.80)]. In axSpA, a therapeutic level could not be identified, but higher adalimumab levels were associated with response. Factors associated with ADAb formation were previous bDMARD use, no methotrexate comedication and the use of adalimumab originator compared with GP2017. Conclusion: Higher adalimumab levels were associated with a better response and improved drug survival for all diagnoses, with a suggested lower threshold of 6.0 mg/l for RA/PsA. This finding, the large variability in drug levels among patients receiving standard adalimumab dose and the high proportion of patients developing ADAbs encourages further investigations into the potential role of therapeutic drug monitoring of adalimumab.

BACKGROUND:Antidrug antibodies to TNF inhibitors might affect clinical outcomes. Proactive therapeutic drug monitoring allows for early detection of antidrug antibodies and might reduce negative clinical consequences. We aimed to explore how antidrug antibodies to the TNF inhibitor infliximab influence treatment outcomes, and to assess the effect of proactive therapeutic drug monitoring. METHODS:This was a predefined exploratory analysis of data from the randomised, controlled NOR-DRUM trials. The trials were conducted in rheumatology, gastroenterology, and dermatology departments at 21 Norwegian hospitals. Adult patients (aged 18-75 years) with immune-mediated inflammatory diseases were randomly assigned to proactive therapeutic drug monitoring or standard infliximab dosing in the NOR-DRUM A trial (30-week follow-up) and the NOR-DRUM B trial (52-week follow-up). Antidrug antibodies were assessed with a drug-sensitive assay before each infusion. The outcomes of remission (at week 30), disease worsening (during 52 weeks), infusion reactions, and infliximab discontinuation were assessed according to the presence of antidrug antibodies and use of therapeutic drug monitoring. FINDINGS:Between March 1, 2017, and Dec 12, 2019, 616 patients were included in the NOR-DRUM trials, of whom 615 had at least one serum infliximab and antidrug antibody assessment and were included in the present analyses. Mean age was 45 years (IQR 32-56), 305 (50%) patients were women, and 310 (50%) patients were men. Antidrug antibodies were detected in 147 (24%) patients. Remission at week 30 occurred in 25 (35%) of 72 patients with antidrug antibodies and 180 (54%) of 335 without antidrug antibodies (risk ratio 0·62 [95% CI 0·45-0·86]; p=0·0037). In patients with antidrug antibodies compared with patients without antidrug antibodies, higher rates were found for: disease worsening over 52 weeks (0·76 per person-year vs 0· 35 per person-year, hazard ratio [HR] 2·02 [95% CI 1·33-3·07]; p=0·0009), infusion reactions (0·16 per person-year vs 0·03 per person-year, HR 17·02 [6·98-41·47]; p<0·0001), and infliximab discontinuation (1·00 per person-year vs 0·20 per person-year, HR 6·64 [4·84-9·11]; p<0·0001). These associations were more pronounced in patients with high concentrations of antidrug antibodies than in those with low concentrations of antidrug antibodies. Independent of antibody status, therapeutic drug monitoring was associated with a lower risk of disease worsening (HR 0·41 [0·29-0·59]; p=0·0001) or an infusion reaction (HR 0·30 [0·12-0·73]; p=0·0076), and was associated with an increase in the rate of infliximab discontinuation (HR 1·37 [1·02-1·83]; p=0·037). INTERPRETATION:In patients where antidrug antibodies were detected, remission was less likely to be reached and sustained, and infusion reaction or discontinuation of infliximab was more likely. Timely detection of antidrug antibodies by proactive therapeutic drug monitoring facilitated treatment decisions that reduced the negative consequences, both regarding infliximab effectiveness and safety. This highlights the role of proactive therapeutic drug monitoring in optimising infliximab therapy. FUNDING:Inter-regional KLINBEFORSK grants and South-Eastern Norway Regional Health Authority grants.

ObjectivesImmune responses following SARS-CoV-2 vaccination in patients with inflammatory bowel disease (IBD) are not well characterized. The aims of this study were to explore the serological response associated with IBD, and immunosuppressive medications including serum concentrations of biologics and thiopurine metabolites.Materials and methodsThis prospective, observational study included adult patients with ulcerative colitis (UC) and Crohn's disease (CD), and healthy controls. Antibodies to the receptor-binding domain of SARS-CoV-2 spike proteins, and serum concentrations of ongoing biologic and immunomodulatory medications were assessed prior to, and 2-5 weeks after the second vaccine dose. Serologic response was defined as anti-Spike antibodies >= 70 AU/ml.ResultsIn 958 IBD patients (380 UC, 578 CD) and 323 healthy controls, the median (Q(1;) Q(3)) anti-Spike antibody level (AU/ml) was lower in patients (618 (192; 4370)) compared to controls (3355 (896; 7849)) (p < 0.001). The antibody levels were lower in CD (439 (174; 3304)) compared to UC (1088 (251; 5975)) (p < 0.001). No associations were demonstrated between antibody levels and serum drug concentrations for TNF inhibitor (TNFi), vedolizumab and ustekinumab. Patients receiving TNFi + thiopurines with a subtherapeutic 6-thioguanine nucleotide (6-TGN) level had higher response rate (93%) compared to patients with 6-TGN within the therapeutic range (53%) (p = 0.003). A diagnosis of UC, mRNA-1273 vaccine, and other treatments than TNFi + thiopurines were associated with humoral response.ConclusionsPatients with CD had an attenuated humoral response to SARS-COV-2 vaccination as compared to patients with UC. The lack of association between serum levels of biologics and serologic response indicates vaccination regardless of proximity to drug administration.

AbbVie, BristolMyers Squibb and Pfizer Inc. ZS has acted as an advisor for AbbVie, Eli Lilly, Gedeon Richter, Novartis, Pfizer Inc and Roche; as a consultant for AbbVie, Eli Lilly, Novartis, Pfizer Inc, Roche and Sanofi; has received grant/research support from Pfizer Inc and UCB; and is a member of the Speakers’ Bureau for AbbVie, Eli Lilly, MSD, Novartis, Pfizer Inc, Roche, Sanofi and UCB. JTG has acted as a consultant for AbbVie, BristolMyers Squibb, Eli Lilly, Genentech, Gilead Sciences and UCB; and has received grant/research support from Pfizer Inc. SY has acted as a consultant for Corbus, Janssen, Kezar Life Sciences and Pfizer Inc; and has received remuneration from Pfizer Inc for their services as a member of the Steering Committee for ORAL Surveillance. DLB served as a member of the Steering Committee for ORAL Surveillance, with funding from Pfizer Inc paid to Brigham and Women’s Hospital; has served on Advisory Boards for AngioWave, Bayer, Boehringer Ingelheim, Cardax, CellProthera, Cereno Scientific, Elsevier Practice Update Cardiology, High Enroll, Janssen, Level Ex, Medscape Cardiology, Merck, MyoKardia, NirvaMed, Novo Nordisk, PhaseBio, PLx Pharma, Regado Biosciences and Stasys; has served on the Board of Directors for AngioWave (stock options), Boston VA Research Institute, Bristol Myers Squibb (stock), DRS.LINQ (stock options), High Enroll (stock), the Society of Cardiovascular Patient Care and TobeSoft; was the Inaugural Chair for the American Heart Association Quality Oversight Committee; has served as a consultant for Broadview Ventures; has been on Data Monitoring Committees for Acesion Pharma, Assistance PubliqueHôpitaux de Paris, Baim Institute for Clinical Research (formerly Harvard Clinical Research Institute, for the PORTICO trial, funded by St. Jude Medical, now Abbott), Boston Scientific (Chair, PEITHO trial), Cleveland Clinic (including for the ExCEED trial, funded by Edwards), Contego Medical (Chair, PERFORMANCE 2), Duke Clinical Research Institute, Mayo Clinic, Mount Sinai School of Medicine (for the ENVISAGE trial, funded by Daiichi Sankyo; for the ABILITYDM trial, funded by Concept Medical), Novartis, Population Health Research Institute and Rutgers University (for the NIHfunded MINT Trial); has received honoraria from the American College of Cardiology (Senior Associate Editor, Clinical Trials and News, ACC. org; Chair, ACC Accreditation Oversight Committee), Arnold and Porter law firm (work related to Sanofi/BristolMyers Squibb clopidogrel litigation), Baim Institute for Clinical Research (formerly Harvard Clinical Research Institute; REDUAL PCI Clinical Trial Steering Committee funded by Boehringer Ingelheim; AEGISII Executive Committee funded by CSL Behring), Belvoir Publications (Editor in Chief, Harvard Heart Letter), Canadian Medical and Surgical Knowledge Translation Research Group (Clinical Trial Steering Committees), Cowen and Company, Duke Clinical Research Institute (Clinical Trial Steering Committees, including for the PRONOUNCE trial, funded by Ferring Pharmaceuticals), HMP Global (Editor in Chief, Journal of Invasive Cardiology), Journal of the American College of Cardiology (Guest Editor; Associate Editor), K2P (CoChair, Interdisciplinary Curriculum), Level Ex, Medtelligence/ ReachMD (CME Steering Committees), MJH Life Sciences, Oakstone CME (Course Director, Comprehensive Review of Interventional Cardiology), Piper Sandler, Population Health Research Institute (for the COMPASS Operations Committee, Publications Committee, Steering Committee and USA national coleader, funded by Bayer), Slack Publications (Chief Medical Editor, Cardiology Today’s Intervention), Society of Cardiovascular Patient Care (Secretary/Treasurer), WebMD (CME Steering Committees) Wiley (Steering Committee), Clinical Cardiology (Deputy Editor), NCDRACTION Registry Steering Committee (Chair), and VA CART Research and Publications Committee (Chair); holds patent interests in sotagliflozin (named on a patent for sotagliflozin assigned to Brigham and Women’s Hospital who assigned to Lexicon; neither DLB nor Brigham and Women’s Hospital receive any income from this patent); research funding from Abbott, Acesion Pharma, Afimmune, Aker Biomarine, Amarin, Amgen, AstraZeneca, Bayer, Beren, Boehringer Ingelheim, Boston Scientific, BristolMyers Squibb, Cardax, CellProthera, Cereno Scientific, Chiesi, CSL Behring, Eisai, Ethicon, Faraday Pharmaceuticals, Ferring Pharmaceuticals, Forest Laboratories, Fractyl, Garmin, HLS Therapeutics, Idorsia, Ironwood, Ischemix, Janssen, Javelin, Lexicon, Lilly, Medtronic, Merck, Moderna, MyoKardia, NirvaMed, Novartis, Novo Nordisk, Owkin, Pfizer Inc, PhaseBio, PLx Pharma, Recardio, Regeneron, Reid Hoffman Foundation, Roche, Sanofi, Stasys, Synaptic, The Medicines Company, 89Bio; royalties from Elsevier (Editor, Braunwald’s Heart Disease); has served as site coinvestigator for Abbott, Biotronik, Boston Scientific, CSI, Endotronix, St. Jude Medical (now Abbott), Philips, SpectraWAVE, Svelte, Vascular Solutions; is a trustee for the American College of Cardiology; and has completed unfunded research for FlowCo and Takeda. GGK is a shareholder of IQVIA; has received grant/research support from AbbVie, Acceleron, Amgen, Arena, AstraZeneca, Cytokinetics, Eli Lilly, Gilead Sciences, GlaxoSmithKline, Huya Bioscience International, Johnson is an employee of the University of North Carolina at Chapel Hill; and has served as a member of the Steering Committee for ORAL Surveillance, with funding from Pfizer Inc paid to the University of North Carolina at Chapel Hill. IV, JW, CW, KK, SM, AY and JLR are employees and stockholders of Pfizer Inc. CAC was an employee and stockholder of Pfizer Inc at the time of this analysis. MHB has acted as a consultant for AbbVie, Eli Lilly, Gilead Sciences, and Pfizer Inc; has received grant/research support from Gilead, Pfizer Inc and UCB; is a member of the Speakers’ Bureau for AbbVie; and is supported by the National Institute for Health Research (NIHR) Manchester Biomedical Research Centre and is in receipt of an NIHR Senior Investigator award.

Background Antidrug antibodies to TNF inhibitors might affect clinical outcomes. Proactive therapeutic drug monitoring allows for early detection of antidrug antibodies and might reduce negative clinical consequences. We aimed to explore how antidrug antibodies to the TNF inhibitor infliximab influence treatment outcomes, and to assess the effect of proactive therapeutic drug monitoring. Methods This was a predefined exploratory analysis of data from the randomised, controlled NOR-DRUM trials. The trials were conducted in rheumatology, gastroenterology, and dermatology departments at 21 Norwegian hospitals. Adult patients (aged 18-75 years) with immune-mediated inflammatory diseases were randomly assigned to proactive therapeutic drug monitoring or standard infliximab dosing in the NOR-DRUM A trial (30-week follow-up) and the NORDRUM B trial (52-week follow-up). Antidrug antibodies were assessed with a drug-sensitive assay before each infusion. The outcomes of remission (at week 30), disease worsening (during 52 weeks), infusion reactions, and infliximab discontinuation were assessed according to the presence of antidrug antibodies and use of therapeutic drug monitoring. Findings Between March 1, 2017, and Dec 12, 2019, 616 patients were included in the NOR-DRUM trials, of whom 615 had at least one serum infliximab and antidrug antibody assessment and were included in the present analyses. Mean age was 45 years (IQR 32-56), 305 (50%) patients were women, and 310 (50%) patients were men. Antidrug antibodies were detected in 147 (24%) patients. Remission at week 30 occurred in 25 (35%) of 72 patients with antidrug antibodies and 180 (54%) of 335 without antidrug antibodies (risk ratio 062 [95% CI 045-086]; p=00037). In patients with antidrug antibodies compared with patients without antidrug antibodies, higher rates were found for: disease worsening over 52 weeks (076 per person-year vs 0 35 per person-year, hazard ratio [HR] 202 [95% CI 133-307]; p=00009), infusion reactions (016 per person-year vs 003 per person-year, HR 1702 [698-4147]; p<00001), and infliximab discontinuation (100 per person-year vs 020 per person-year, HR 664 [484-911]; p<00001). These associations were more pronounced in patients with high concentrations of antidrug antibodies than in those with low concentrations of antidrug antibodies. Independent of antibody status, therapeutic drug monitoring was associated with a lower risk of disease worsening (HR 041 [029-059]; p=00001) or an infusion reaction (HR 030 [012-073]; p=00076), and was associated with an increase in the rate of infliximab discontinuation (HR 137 [102-183]; p=0037). Interpretation In patients where antidrug antibodies were detected, remission was less likely to be reached and sustained, and infusion reaction or discontinuation of infliximab was more likely. Timely detection of antidrug antibodies by proactive therapeutic drug monitoring facilitated treatment decisions that reduced the negative consequences, both regarding infliximab effectiveness and safety. This highlights the role of proactive therapeutic drug monitoring in optimising infliximab therapy.

Background The durability of vaccine-induced humoral immunity against SARS-CoV-2 in patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressive therapy is not known. The aim of this study was to compare the persistence of anti-Spike antibodies following two-dose SARS-CoV-2 vaccination between IMID patients and healthy controls and to identify factors associated with antibody decline. Methods IMID patients on immunosuppressive medication enrolled in the prospective observational Nor-vaC study were included. Participants received two-dose SARS-CoV-2 vaccination. Serum collected at two time points following vaccination (first assessment within 6-48 days, second within 49-123 days) were analyzed for antibodies binding the receptor-binding domain (RBD) of the SARS-CoV-2 Spike protein. Multivariable regression models estimated percent reduction in anti-RBD over 30 days and factors associated with reduction. Results A total of 1108 patients (403 rheumatoid arthritis, 195 psoriatic arthritis, 195 spondyloarthritis, 124 ulcerative colitis, 191 Crohn's disease) and 134 controls provided blood samples within the defined intervals (median 19 days [IQR 15-24] and 97 days [87-105] after second vaccine dose). Antibody levels were lower in patients compared to controls at both time points, with median anti-RBD 2806 BAU/ml [IQR 1018-6068] in patients and 6187 BAU/ml [4105-7496] in controls (p<0.001) at first assessment, and 608 BAU/ml [IQR 58-1053] in patients and 1520 BAU/ml [979-3766] in controls (p<0.001) at second assessment. At second assessment, low anti-RBD antibody levels (defined as <200 BAU/ml) were found in 449 (41%) patients, and 6 (5%) controls (p<0.001). The change was - 83% in patients and - 66% in controls (p<0.001). Patients had a greater estimated 30 days percent reduction in anti-RBD levels compared to controls - 4.9 (95% CI - 7.4 to - 2.4), (p<0.05). Among therapies, mono- or combination treatment with tumor necrosis factor inhibitors was associated with the greatest decline. Conclusions Within 4 months after vaccination, antibody levels declined considerably in both IMID patients and controls. Patients had lower initial antibody levels and a more pronounced decline compared to healthy controls and were therefore more likely to decline to low antibody levels. These results support that IMID patients need additional vaccine doses at an earlier stage than healthy individuals.

BackgroundImmunogenicity is a leading cause of treatment failure to TNF inhibitors, and also affects drug safety. Variations in HLA class II genes have been suggested to predispose to anti-drug antibody formation (ADA), but characterisation of biologically relevant HLA haplotypes, based on high-resolution genotyping, is lacking.ObjectivesTo assess associations between HLA loci and formation of ADA to infliximab across different immune mediated inflammatory diseases.MethodsPatients with immune mediated inflammatory diseases on infliximab therapy (N=612; 181 spondyloarthritis, 120 rheumatoid arthritis, 72 psoriatic arthritis, 114 ulcerative colitis, 80 Crohn’s disease and 45 psoriasis) participating in the Norwegian Drug Monitoring (NOR-DRUM) trials (1, 2) were included in the present analyses. Neutralising ADA were assessed with an automated fluorescence assay at each infusion. Next generation sequencing-based HLA typing was performed. Associations with ADA formation were assessed at locus, allele, haplotype and amino acid level. Peptide binding predictions for infliximab were performed.ResultsADA were detected in 147 patients (24%). Significant associations were shown between ADA and several HLA loci, whereas conditional analyses indicated HLA-DQB1 (p=1.4x10-6) as the primary risk locus. Highest risk of ADA formation was seen for patients carrying at least one of the HLA-DQ2 haplotypes; DQB1*02:01~DQA1*05:01 and DQB1*02:02~DQA1*02:01 (OR 3.18, 95% CI 2.15 to 4.69, p=5.9x10-9) (Figure 1). These findings were consistent across diagnoses (Table 1), and remained significant when adjusting for other possible predictors of ADA. Computational predictions indicated that both these HLA-DQ2 haplotypes could strongly bind two peptide motifs (INTVESEDI and VYACEVTHQ) in the infliximab heavy and light chain.Table 1.HLA-DQ2 carrier frequencies according to the different disease phenotypes and for all diagnosis combinedDiagnosisHLA-DQ2 carrier-frequency among patients with ADA formationHLA-DQ2 carrier-frequency among patients without ADA formationP-valueRA (N=120)0.3160.1340.02PsA (N=72)0.550.2310.01SpA (N=181)0.3640.1820.02UC (N=114)0.5560.2640.006CD (N=80)0.4290.3030.33Ps (N=45)0.8670.2670.0004All disease phenotypes0.4690.2175.9x10-9ConclusionThe risk of ADA to infliximab was three-fold higher in patients carrying the HLA-DQ2 risk haplotypes across diseases. A biological role for the HLA-DQ2 molecules encoded by the two different HLA-DQ2 risk haplotypes in the formation of ADA was further supported by peptide binding predictions. These novel findings provide promise for future incorporation of HLA-DQ2 testing to facilitate personalised treatment decisions.References[1]Syversen SW et al. Jama. 2021;326(23):2375-84.[2]Syversen SW et al. Jama. 2021;325(17):1744-54.Disclosure of InterestsMarthe Kirkesæther Brun: None declared, Kristin Hammersbøen Bjørlykke: None declared, Marte K. Viken: None declared, Bitte Stenvik Employee of: is a former employee of UCB Pharma, Rolf A. Klaasen: None declared, Johanna Gehin: None declared, David J Warren: None declared, Joe Sexton: None declared, Øystein Sandanger: None declared, Cato Mørk Speakers bureau: Novartis Norway, LEO Pharma, ACO Hud Norge, Cellgene, Abbvie, and Galderma Nordic AB., Consultant of: Novartis Norway, LEO Pharma, ACO Hud Norge, Cellgene, Abbvie, and Galderma Nordic AB., Tore K. Kvien Speakers bureau: Amgen, Celltrion, Evapharma, Gilead, Hikma, Mylan, Oktal, Pfizer, Sandoz, Sanofi, UCB, Consultant of: Amgen, Celltrion, Evapharma, Gilead, Hikma, Mylan, Oktal, Pfizer, Sandoz, Sanofi, UCB, Grant/research support from: AbbVie, Amgen, BMS, Novartis, Pfizer, UCB, Espen A Haavardsholm Speakers bureau: Pfizer, AbbVie, Celgene, Novartis, Janssen, Gilead, Eli-Lilly, and UCB, Consultant of: Pfizer, AbbVie, Celgene, Novartis, Janssen, Gilead, Eli-Lilly, and UCB, Jørgen Jahnsen Speakers bureau: AbbVie, Boerhinger Ingelheim, BMS, Celltrion, Giliad, Hikma, Janssen Cilag, Novartis, Orion Pharma, Pfizer, Roche, Takeda, and Sandoz, Consultant of: AbbVie, Boerhinger Ingelheim, BMS, Celltrion, Giliad, Hikma, Janssen Cilag, Novartis, Orion Pharma, Pfizer, Roche, Takeda, and Sandoz, Guro Løvik Goll Speakers bureau: Pfizer, AbbVie, Boehringer Ingelheim, Roche, Orion pharma, Sandoz, Novartis, and UCB, Consultant of: Pfizer, AbbVie, Boehringer Ingelheim, Roche, Orion pharma, Sandoz, Novartis, and UCB, Benedicte A. Lie: None declared, Kristin Kaasen Jørgensen Speakers bureau: Roche, BMS, Celltrion, and Norgine., Consultant of: Roche, BMS, Celltrion, and Norgine., Nils Bolstad Speakers bureau: Roche Pharmaceuticals and Novartis, Consultant of: Janssen, Silje Watterdal Syversen: None declared

Anti‐drug antibodies (ADAb) frequently form early in the treatment course of infliximab and other tumour necrosis factor (TNF) inhibitors, leading to treatment failure and adverse events.

Importance:Proactive therapeutic drug monitoring (TDM), defined as individualized drug dosing based on scheduled monitoring of serum drug levels, has been proposed as an alternative to standard therapy to maximize efficacy and safety of infliximab and other biological drugs. However, whether proactive TDM improves clinical outcomes when implemented at the time of drug initiation, compared with standard therapy, remains unclear.Objective:To assess whether TDM during initiation of infliximab therapy improves treatment efficacy compared with standard infliximab therapy without TDM.Design, Setting, and Participants:Randomized, parallel-group, open-label clinical trial of 411 adults with rheumatoid arthritis, spondyloarthritis, psoriatic arthritis, ulcerative colitis, Crohn disease, or psoriasis initiating infliximab therapy in 21 hospitals in Norway. Patients were recruited from March 1, 2017, to January 10, 2019. Final follow-up occurred on November 5, 2019.Interventions:Patients were randomized 1:1 to receive proactive TDM with dose and interval adjustments based on scheduled monitoring of serum drug levels and antidrug antibodies (TDM group; n = 207) or standard infliximab therapy without drug and antibody level monitoring (standard therapy group; n = 204).Main Outcomes and Measures:The primary end point was clinical remission at week 30.Results:Among 411 randomized patients (mean age, 44.7 [SD, 14.9] years; 209 women [51%]), 398 (198 in the TDM group and 200 in the standard therapy group) received their randomized intervention and were included in the full analysis set. Clinical remission at week 30 was achieved in 100 (50.5%) of 198 and 106 (53.0%) of 200 patients in the TDM and standard therapy groups, respectively (adjusted difference, 1.5%; 95% CI, -8.2% to 11.1%; P = .78). Adverse events were reported in 135 patients (68%) and 139 patients (70%) in the TDM and standard therapy groups, respectively.Conclusions and Relevance:Among patients with immune-mediated inflammatory diseases initiating treatment with infliximab, proactive therapeutic drug monitoring, compared with standard therapy, did not significantly improve clinical remission rates over 30 weeks. These findings do not support routine use of therapeutic drug monitoring during infliximab induction for improving disease remission rates.Trial Registration:ClinicalTrials.gov Identifier: NCT03074656.

OBJECTIVES:To identify the therapeutic range for etanercept and to assess the incidence of anti-etanercept antibody formation. METHODS:Associations between etanercept serum concentration and disease activity as well as treatment response were examined in a longitudinal observational study of rheumatoid arthritis patients starting etanercept. Disease activity was assessed by ultrasound (grey scale and power Doppler), 28-joint Disease Activity Score (DAS28), Simplified Disease Activity Index, plasma calprotectin and C reactive protein. Etanercept concentration and anti-etanercept antibodies were analysed using automated in-house fluorescence assays. RESULTS:A total of 89 patients were included, whereof 66% were biological disease-modifying antirheumatic drug (DMARD) naïve and 91% used concomitant synthetic DMARD. At 3 months, the median etanercept concentration was 1.8 (IQR 1.1-2.5) mg/L. Longitudinal associations were found between etanercept concentration and disease activity assessed by plasma calprotectin, C reactive protein and DAS28, but not between etanercept concentration and improvement in disease activity by any of the parameters at 3, 6 or 12 months of treatment. Etanercept concentrations were not significantly different among patients who achieved response or remission, compared with non-response or non-remission. Hence, no therapeutic range could be identified. None of the patients developed anti-etanercept antibodies. CONCLUSION:Despite the use of sensitive and objective markers of inflammation, a therapeutic range could not be identified for etanercept. Hence, this study suggests that proactive therapeutic drug monitoring is unlikely to benefit rheumatoid arthritis patients treated with etanercept, but a potential benefit in certain clinical situations cannot be excluded.

A lack or loss of response to TNFα inhibitors (TNFi) has been associated with low serum drug levels and formation of anti-drug antibodies (ADAb). Therapeutic drug monitoring (TDM), an individualised treatment strategy based on regular assessments of serum drug levels, has been suggested to optimise efficacy of TNFi. It is still unclear if TDM improves clinical outcomes, and the value of TDM has recently been included in the research agenda across different specialities. This first randomised controlled trial on the effectiveness of TDM in a range of immune mediated inflammatory diseases including rheumatic diseases, the NORwegian DRUg Monitoring trial part A (NOR-DRUM (A)) focus on the induction period of infliximab (INX) treatment.To assess if TDM is superior to standard treatment in order to achieve remission in patients starting INX.In the investigator-initiated, randomised, open-label, multicentre NOR-DRUM (A) study, adult patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), spondyloarthritis (SpA), ulcerative colitis (UC), Crohn’s disease (CD) and psoriasis (Ps) starting INX therapy were randomly assigned to administration of INX according to a treatment strategy based on TDM (TDM arm) or to standard administration of INX without TDM (control arm). Study visits were conducted at each infusion. The primary endpoint was remission at week 30. In the TDM arm, the dose and interval were adjusted according to INX trough levels to reach the therapeutic range (Figure 1). If the patient developed significant levels of ADAb, INX was terminated. To guide the investigators, the TDM strategy was integrated in an interactive eCRF. The primary endpoint was analysed by mixed effect logistic regression in the full analyses set (FAS), adjusting for diagnoses. Infections and infusion reactions were specified as adverse events (AEs) of special interest.Clinical trial.gov:NCT03074656We enrolled 411 patients at 21 study centres between January 2017 and December 2018. 398 patients (RA 80, PsA 42, SpA 117, UC 80, CD 57, Ps 22) received the allocated strategy and were included in the FAS population. Demographic and baseline characteristics were comparable in both arms. TDM was not found to be superior to standard treatment with regard to the primary outcome. Remission at week 30 was reached in 100 (53%) and 106 (54%) of the patients in the TDM and control arm, respectively (adjusted difference, 1.5%; 95% confidence interval (CI), -8.2 to 11.1, p=0.78) (Figure 2). Consistent results were shown for all the secondary endpoints (Figure 3) and in the sensitivity analyses. Twenty patients (10%) in the TDM arm and 30 patients (15%) in the control arm developed significant levels of ADAb. The number of adverse events (AE) was similar in both groups, however infusion reactions were less frequent (5 patients (2.5%) vs 16 patients (8.0%)) in the TDM arm (difference 5.5% (95% CI 1.1, 9.8%))NOR-DRUM (A) is the first randomised trial to address effectiveness of TDM in the induction period of TNFi treatment, and the first trial to address TDM in rheumatic diseases. In this study, TDM was not superior to standard treatment in order to achieve remission. Although improved safety is indicated by a reduction in infusion reactions, implementation of TDM as a general strategy in the induction period of INX is not supported by the NOR-DRUM (A) study.Silje Watterdal Syversen Speakers bureau: Roche, Thermo Fisher, Guro Løvik Goll Consultant of: Novartis, Pfizer, Speakers bureau: Abbvie, Biogen, Boehringer Ingelheim, Orion Pharma, Eli Lilly, Novartis, Pfizer, MSD, Roche, UCB, Kristin Kaasen Jørgensen Consultant of: AOP Orphan, Celltrion, Sandoz, Speakers bureau: Norgine, Tillots, Øystein Sandanger: None declared, Joe Sexton: None declared, Inge Olsen: None declared, Johanna Gehin Speakers bureau: Roche, Marthe Kirksæther Brun: None declared, David Warren: None declared, Cato Mørk Consultant of: Abbot, Novartis, Celagene, Almiral, Galderma, ACO, Almiral, ACO, Speakers bureau: Novartis, Abbott, Abbvie, Celegene, LEO, Almiral, Galderma, Tore K. Kvien Grant/research support from: Received grants from Abbvie, Hospira/Pfizer, MSD and Roche (not relevant for this abstract)., Consultant of: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Paid instructor for: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Speakers bureau: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Jørgen Jahnsen Consultant of: AbbVie, Boerhinger Ingelheim, Celltrion, Ferring, Janssen, Meda, MSD, Norgine, Novartis, Orion Pharma, Pfizer, Pharmacosmos, Takeda, and Sandoz., Speakers bureau: AbbVie, Astro Pharma, Boerhinger Ingelheim, BMS, Celltrion, Ferring, Hikma, Janssen, Meda, MSD, Napp Pharma, Orion Pharma, Pfizer, Pharmacosmos, Roche, Takeda, Tillotts and Sandoz, Nils Bolstad Consultant of: Pfizer, Janssen, Speakers bureau: Orion Pharma, Napp Pharmaceuticals, Takeda, Roche, Novartis, Espen A Haavardsholm Grant/research support from: AbbVie, UCB Pharma, Pfizer Inc, MSD Norway, Roche Norway, Consultant of: Pfizer, AbbVie, Janssen-Cilag, Gilead, UCB Pharma, Celgene, Lilly, Paid instructor for: UCB Pharma, Speakers bureau: Pfizer, AbbVie, UCB Pharma, Celgene, Lilly, Roche, MSD

The successful use of chimeric antigen receptor (CAR) for hematological cancer treatment has influenced the direction taken in translational research toward an increasing focus on personalized targeted immunotherapy. Thus, a growing number of labs worldwide are now interested in testing their old antibody collections in this format to broaden the spectrum of utility and improve safety and efficacy. We herein present a straightforward protocol for the identification of an antibody from a hybridoma and the design of the single chain fragment that will be placed on the extracellular part of the CAR construct. We further show how to test the expression and the activity of the construct in primary T cells. We illustrate our demonstration with two new CARs targeted against the B cell receptor, more precisely the light chains κ and λ, that represent potential alternatives to the CD19 CAR used in the treatment of B-cell malignancies.

Abstract Objectives To identify a therapeutic target interval for certolizumab pegol drug levels and examine the influence of anti-drug antibodies in patients with inflammatory joint diseases. Methods Certolizumab pegol and anti-drug antibody levels were measured in serum samples collected after 3 months of certolizumab pegol treatment in 268 patients with inflammatory joint diseases (116 axial spondyloarthritis, 91 rheumatoid arthritis and 61 psoriatic arthritis) in the NOR-DMARD study. Treatment response was defined by Ankylosing Spondylitis Disease Activity Score Clinically important improvement in axial spondyloarthritis, European League Against Rheumatism good/moderate response in rheumatoid arthritis, and improvement in 28-joint Disease Activity Score of ≥ 0.6 in PsA. Serum drug levels and anti-drug antibodies were analysed using automated in-house assays. Results Certolizumab pegol serum levels varied considerably between individuals (median (IQR) 32.9 (17.3–43.9) mg/L). Certolizumab pegol level ≥ 20 mg/L was associated with treatment response for the total inflammatory joint disease population, with odds ratio (OR) 2.3 (95% CI 1.2–4.5, P = 0.01) and OR 1.9 (95% CI 1.0–3.5, P = 0.05) after 3 and 6 months of treatment, respectively. For individual diagnoses, this association was most consistent for axial spondyloarthritis, with OR 3.4 (95% CI 1.0–11.1, P < 0.05) and OR 3.3 (95% CI 1.0–10.8, P < 0.05), respectively. Certolizumab pegol level > 40 mg/L was not associated with any additional benefit for any of the diagnoses. Anti-drug antibodies were detected in 6.1% (19/310) of samples and were associated with low certolizumab pegol levels (P < 0.01). Conclusions Serum certolizumab pegol levels 20–40 mg/L were associated with treatment response in inflammatory joint diseases. Our study is the first to show this association in axial spondyloarthritis and psoriatic arthritis patients. The results suggest a possible benefit of therapeutic drug monitoring in patients with inflammatory joint disease on certolizumab pegol treatment. Trial registration NCT01581294, April 2012.

Background: Belatacept (Nulojix; Bristol-Myers Squibb, New York, NY) is a biological immunosuppressive drug used for the prophylaxis of acute rejection after renal transplantation. Few studies have described belatacept pharmacokinetics, and the effect of therapeutic drug monitoring has not been investigated. We have developed a drug-capture assay (using drug target) to measure belatacept in serum and applied this assay in a pharmacokinetic study in renal transplant recipients. Methods: CD80 was used to trap belatacept onto streptavidin-coated wells. Captured drug was quantified using Eu3+-labeled protein A and time-resolved fluorescence. The assay was applied in a pilot pharmacokinetic study in renal transplanted patients receiving belatacept infusions. Belatacept serum concentrations were determined at several time points between belatacept infusions. A simple population pharmacokinetic model was developed to visualize measured and predicted belatacept serum concentrations. Results: The assay range was 0.9-30 mg/L with accuracy within 91%-99% and coefficients of variation ranging from 1.2% to 3.6%. Predilution extended the measurement range to 130 mg/L with an accuracy of 90% and coefficients of variation of 3.8%. Samples were stable during storage at 48 degrees C for 15 days and during 2 freeze-thaw cycles. Belatacept concentrations were determined in a total of 203 serum samples collected during 26 infusion intervals from 5 renal transplant recipients. The population pharmacokinetic model visualized both measured and predicted concentrations. Conclusions: We have developed an automated, accurate, and precise assay for the determination of belatacept serum concentrations. The assay was successfully applied in a pharmacokinetic study in renal transplant recipients receiving belatacept infusions.

Traditional protocols for preparing Escherichia coli for electroporation are laborious and often deliver highly variable transformation efficiencies. Many laboratories resort to purchasing expensive commercially prepared cells. This article describes a simple method for producing electrocompetent E. coli by centrifuging bacteria through a glycerol/mannitol density cushion. The method is rapid and replaces tedious multistep procedures with two 15-min centrifugations. Standard cloning strains consistently produce more than 8×109transformants/μg pUC18, whereas the strains TG1 and LE392 display efficiencies of more than 3×1010/μg DNA.