THU0177 DURABILITY OF RESPONSE AMONG PATIENTS WITH RHEUMATOID ARTHRITIS INITIATING TOCILIZUMAB: DATA FROM THE US-BASED CORRONA RHEUMATOID ARTHRITIS REGISTRY
Authors: D. A. Pappas, T. Blachley, J. H. Best, S. Zlotnick, W. Reiss, K. Emeanuru, J. M. Kremer
Journal: Annals of the Rheumatic Diseases (2020)

Background: Understanding the durability of response to biologics and factors associated with failure to maintain response in a real-world setting can inform treatment decisions for patients with rheumatoid arthritis (RA). Objectives: To evaluate the durability of response and identify factors associated with decreased durability in US patients with RA initiating tocilizumab (TCZ) in routine clinical practice. Methods: TCZ-naïve patients enrolled in the Corrona RA registry who initiated TCZ (subcutaneous [SC] or intravenous [IV]) after January 1, 2010 and had ≥1 follow-up visit were included. Durability of response was defined as maintaining continuous TCZ and: (a) a minimum clinically important difference (MCID) in clinical disease activity index (CDAI) (defined as an improvement in CDAI compared to baseline of: ≥2 if baseline CDAI ≤10; ≥6 if baseline &gt;10 to ≤22; ≥11 if baseline &gt;22) or (b) low disease activity (LDA; CDAI ≤10). Patient response was no longer durable upon the first: discontinuation of TCZ or failure to maintain MCID or LDA. Secondary analyses estimated durability after including only patients: (a) with reported reasons for discontinuation (patients with non-medical reasons for discontinuation [eg, insurance coverage] were censored) or (b) who initiated TCZ-IV. Durability was calculated with Kaplan-Meier survival analysis. Cox proportional hazards modeling identified factors associated with durability. Results: A total of 1789 TCZ initiators (TCZ-IV, n=1284) were identified; 861, 483, and 298 patients were persistent and had follow-up visits at 1, 2, and 3 years, respectively. At baseline, the mean (SD) age was 58.5 (12.6) years, duration of RA was 12.0 (9.6) years and CDAI score was 23.2 (14.2). Most patients (93.4%) had prior biologic use and 67.4% had received ≥2 prior biologics. Among patients with follow-up data available at 1, 2 and 3 years, MCID in CDAI was achieved by 56.3% (261/464), 67.3% (183/272) and 69.8% (113/162), respectively. Overall, MCID durability remained above 50% after 36 months of follow-up, and the same is true when including only patients with reported reasons for discontinuation ( Fig 1 ). For TCZ-IV initiators, median MCID durability was 26 months ( Fig 1 ). For all MCID durability analyses, factors associated with reduced hazard of failure included increased duration of RA and higher baseline CDAI, while higher hazard of failure was associated with history of malignancy or diabetes ( Fig 2 ). Among patients with follow-up data available, LDA was achieved in 53.7% (249/464), 60.3% (164/272) and 67.3% (109/162) at 1, 2 and 3 years, respectively. The overall median (95% CI) LDA durability was 13.0 (12.0, 20.0) months; when including only patients with reported reasons for discontinuation it was 13.0 (9.0, 29.0) months; among TCZ-IV initiators it was 13.0 (10.0, 19.0) months. Factors associated with an increased hazard of failing to maintain LDA included history of malignancy and, in contrast to MCID, higher baseline CDAI. Conclusion: In this real-world RA population who initiated TCZ, most patients received ≥2 prior biologics. Median durability of response (MCID) was &gt;3 years. Among factors associated with shorter durability of response, history of malignancy was significant in all analyses. Acknowledgments: This study was sponsored by Corrona, LLC. Corrona is supported through contracted subscriptions with multiple pharmaceutical companies. The abstract was a collaborative effort between Corrona and Genentech, Inc., with financial support provided by Genentech, Inc. Disclosure of Interests: Dimitrios A Pappas: None declared, Taylor Blachley Employee of: Corrona, LLC, Jennie H. Best Shareholder of: Genentech, Inc., Employee of: Genentech, Inc., Steve Zlotnick Shareholder of: Genentech, Inc., Employee of: Genentech, Inc., William Reiss Shareholder of: Genentech, Inc., Employee of: Genentech, Inc., Kelechi Emeanuru Employee of: Corrona, LLC – employment, Joel M Kremer Shareholder of: May own stocks and opinions, Grant/research support from: Research and consulting fees from AbbVie Inc., Consultant of: AbbVie, Amgen, BMS, Genentech, Inc., Gilead, GSK, Lilly, Pfizer, Regeneron and Sanofi, Employee of: Corrona, LLC employee