P263 Should we advocate biologic dose-reduction in patients with AxSpA?
Authors: Rossen Liz Van , Boyle Cathal , Chan Antoni , Gaffney Karl , Gilbert Annie , Harris Claire , Machado Pedro , Liliana Santos , Sengupta Raj , Keat Andrew 
Published: April 2020

Abstract

Background
Dose optimisation of biologic drugs is attractive on cost and safety grounds. As in RA, some patients with axSpA who respond well to TNF-inhibitor (TNFi) drugs can reduce the dose and remain symptomatically well. However, there are no clear data to support dose reduction strategies nor to identify those likely, and those unlikely, to respond to lower dose treatment.

Methods
71 patients, from 6 UK centres, who fulfilled criteria for AS (modified New York criteria) or AxSpA (ASAS criteria) and who had reduced their dose of TNFi therapy were identified and followed up for 24 months. All were stable responders to TNFi treatment; their responses to treatment fulfilled NICE criteria and were maintained for at least six months by the time of dose reduction. Those who reverted to full-dose treatment and those who did not were identified and data about demographics, disease activity and patients’ approaches to dose reduction were recorded.

Results
55 (77.5%) patients remained on lower-dose treatment (REM) and 16 (22.5%) reverted to full-dose (REV). Mean dose reduction for each of the 4 agents was adalimumab 39%, etanercept 39%, golimumab 26%, and infliximab 46%. Overall dose reduction was 39% and 44% for REM and REV patients respectively. Both groups responded equally to treatment by all measures at dose reduction. In this small study, the data suggest that female gender and younger age are associated with reversion and that REV patients scored lower on BASDAI and CRP at the initiation of TNFi treatment. REV patients’ mean BASDAI, BASFI, BASMI scores increased from dose reduction to dose reversion but mean CRP scores decreased from 3.76 to 3.5mg/dl (7.9%). Even at the point of reversion REV patients still met original response criteria. The majority of patients in both groups reached the decision jointly with clinicians. 62 (89.9%) patients were either confident or neither worried nor confident about the decision to reduce the dose. Patients’ approach to dose-reduction was not associated with reversion and neither the duration of disease nor the time to initiation of biologic treatment appeared to associate with the likely success or failure of reduced dose TNFi treatment. Men with high initial CRP levels appear likely to respond well to biologic dose-reduction. The worsening of symptoms but maintenance of low CRP levels raises questions as to the mechanisms underpinning dose-reversion.

Conclusion
77.5% patients in this study continued to respond well to a mean 39% reduction in biologic dose for 2 years. In the absence of long-term efficacy data, advocating dose-reduction to stable responders is appropriate.

Disclosures
L. Van Rossen: Consultancies; Novartis, UCB. Honoraria; Abbvie, Novartis, pfizer, UCB. Grants/research support; EKHUFT, UCB. C. Boyle: Honoraria; Novartis. A. Chan: None. K. Gaffney: Consultancies; Abbvie, UCB, Pfizer, Novartis, Lilly. Honoraria; Abbvie, UCB, Pfizer, Novartis, Lilly. Member of speakers’ bureau; Abbvie, UCB, Pfizer, Novartis, Lilly. Grants/research support; Abbvie, UCB, Pfizer, Novartis, Lilly. A. Gilbert: Other; consultant for Boehringer Ingelheim Germany as a Global Patient Relations manager working in Scleroderma. C. Harris: Honoraria; Novartis, UCB. P. Machado: Consultancies; Abbvie, BMS, Celgene, Janssen, MSD, Novartis, Pfizer, Roche and UCB. Honoraria; Abbvie, BMS, Celgene, Janssen, MSD, Novartis, Pfizer, Roche and UCB. S. Liliana: None. R. Sengupta: Consultancies; Abbvie, Biogen, Celgene, Novartis, UCB. Honoraria; Abbvie, Biogen, Celgene, Novartis, UCB. A. Keat: None.