AB1267 Bio-similar to bio-originator switchback: not a reliable quality indicator
Authors: S.Y. Lee, M.C.H. Szeto, J.B. Galloway
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> SB4 in an etanercept biosimilar which was licensed by the EMA in January 2016 for clinical use. Switching etanercept treated patients from reference etanercept (ETN) to SB4 can delivera substantial saving in drug costs. The SB4 to ETN switchback rate is often scrutinised by commissioners and clinicians, as it may be a quality indicator for the switch process. <h3>Objectives</h3> To evaluate SB4 drug survival andthe SB4 to ETN switchback rate in our cohort of patients with Rheumatoid Arthritis, Axial Spondyloarthropathy and Psoriatic Arthritis. <h3>Methods</h3> This was a retrospective observational study of 56 patients who were switched from ETN to SB4 in December 2016 at Kings College Hospital. Clinical data was collected 8 months post-switch to establish the number of patients in whom SB4 had been discontinued, the reasons for discontinuation, and the switchback rate. <h3>Results</h3> 84% (n= 47) of patients remained on SB4 at 8 months following the switch. Of the 9 patients who discontinued SB4, 89% (n=8) was due to loss of efficacy, whilst 11% (n=1) reported side effects. Of these, 78% (n=7) were switched over to a 3rd biologic agent, whilst 22% (n=2) were switched back to ETN. The median pre-SB4 switch DAS score for patients with RA who were switched to a 3rd biologic agent was 4.23 (Range: 2.59–7.65), whilst that of those switched back to ETN was 4.08 (Range: 3.35–4.81). <h3>Conclusions</h3> This switch back rate to ETN is considerably lower than what has been reported in the literature.<sup>1–3</sup> There appears to be a preference for switching patients to an alternative biologic agent, rather than switching patients back to the bio-originator. This could be explained by inadequate disease control on etanercept, which has been unmasked under the scrutiny of the biosimilar switch process. An alternative explanation could be that our local clinical commissioning group offers financial incentives if the department maintains a high percentage of etanercept treated patients on SB4. Hence, as prescribing practice can beinfluenced by both clinical factors and external targets, utilizing the switchback rate from biosimilar drugs to bio-originators is not a reliable indicator of the quality of biosimilar switch process. <h3>References</h3> [1] Hendricks O, Hørslev-Petersen K. When etanerceptswitch fails: Clinical considerations [abstract]. <i>Arthritis Rheumatol</i>2017;69(suppl 10). [2] Dyball S, Hoskins V, Christy-Kilner S, Haque S. Effectiveness and tolerabilityof Benepali in rheumatoid arthritis patients switched from enbrel [abstract]. <i>ArthritisRheumatol</i> 2017;69(suppl 10). [3] Holroyd C, Wallis D, Bennett S, et al. AB0377 Switching from bio-original etanercept to biosimilar etanercept sb4: Patient acceptability and outcomes inthe real world. <i>Annals of the Rheumatic Diseases</i> 2017;76:1180. <h3>Acknowledgements</h3> We thank the Rheumatologydepartment at Kings College Hospital NHS Foundation Trust for their kindassistance. <h3>Disclosure of Interest</h3> None declared