was added as study site (but the site never included any patients) 2September 24 th 2018The biosimilar drugs Imraldi and Amgevita (adalimumab) was added as approved study drugs as all patients treated with adalimumab per national guideline had to switch to biosimilar adalimumab in the form of Imraldi or Amgevita. 3March 8 th 2019The biosimilar drug Zessly (infliximab) was added as approved study drug as all patients treated with infliximab per national guideline had to switch to biosimilar infliximab in the form of Zessly. Moreover, the eligibility criteria was revised to allow inclusion of patients in sustained LDA during ≥12 months. 4September 5 th 2019The Department of Rheumatology, Silkeborg Regional Hospital, was added as study site 5November 30 th 2020The biosimilar drugs Erelzi (etanercept) and Hyrimoz (adalimumab) was added as approved study drugs as all patients treated with etanercept or adalimumab per national guideline had to switch to biosimilar Erelzi or Hyrimoz, respectively. 6March 20 th 2020Suspension of patient enrolment due to the national implication of the COVID-19 pandemic to the Danish health care system. Moreover, remote monitoring by telephone contact was allowed for the following visits: month 4, month 8, month 12, and month 24. The primary endpoint assessment (visit 18 month) was considered to be essential to the patients and the trial; therefore, the visit was conducted as an outpatient consultation. Similarly, subacute visits due to symptoms of flare were also considered to be essential; thus, encouraged to be conducted as an outpatient consultation. 7April 2 nd 2020The inclusion period was closed 1 month before scheduled due to the continued national COVID-19 implication to the Danish health care system. 8June 12 th 2020Remote monitoring, due to the implication of the COVID-19 pandemic, was lifted; thus, all trial visits were onwards conducted as an outpatient consultation in accordance with the trial protocol.
S4Supplementary Data S2: Information on randomisation and allocation.A computer-generated allocation sequence was created in SAS PROC PLAN by senior biostatistician Robin Christensen (RC) who had no clinical involvement in the trial. Patients were allocated in permuted blocks of three to six stratified by trial site (Aalborg, Aarhus, Odense, or Silkeborg), diagnosis (RA, PsA, or axSpA) and biologic failure history (currently on biologic number ≤2, or ≥3). The allocation sequence was only accessible to RC and the independent data manager Johanne Hovgaard Winther (JHW). JHW entered the sequence into a dedicated electronic case report form (e-CRF) in Research Electronic Data Capture (REDCap). A randomisation ratio of 2:1 (tapering:control) was chosen to gain more data on the tapering group for exploratory sub-analyses; however, as discussed in the manuscript the trial is not powered for the sub-analyses. The unequal randomisation ratio with more patients allocated to the tapering group exposes a larger proportion of patients to the risk of flare. However, the potential harm is co...