SAT0209 Early Response to Tocilizumab (TCZ) and Benefit of Continued TCZ Treatment in Partial TCZ Responders: Results of the Mirai-Study
Authors: T. Dörner, G.-R. Burmester, H.-P. Tony, C. Iking-Konert, J. Kaufmann, P. Kästner, H. Kellner, R. Kurthen, S. Wagner, M.A. Peters, H. Schulze-Koops
Journal: Annals of the Rheumatic Diseases (2015)

<h3>Background</h3> MIRAI (NCT01332994) investigated the early response at week 16 to the IL-6 inhibitor tocilizumab (TCZ). Patients who only partially responded may benefit from continued TCZ treatment. Non-responders to TCZ subsequently received 1 cycle of rituximab (RTX; anti-CD20 therapy). <h3>Objectives</h3> We report efficacy results of early TCZ responders (week 16) and those of partial TCZ responders who continued TCZ treatment (week 32). <h3>Methods</h3> MIRAI was a German, multicenter, two-arm, open-label, phase-III-study. A homogeneous population of biological naïve patients (pts) with moderate/severe active RA who inadequately responded to traditional DMARDs was included. All pts received 4 TCZ infusions (8 mg/kg, q4w; 1st treatment period). At week 16, early TCZ responder (DAS28&lt;2.6) completed the study; partial responders (ΔDAS28&gt;1.2 or DAS28≥2.6 and ≤3.2) received further 4 TCZ infusions; non-responders (ΔDAS28≤1.2 and DAS28&gt;3.2) received subsequent RTX treatment (1g each at weeks 16 and 18). At week 32, DAS28/ACR/ CDAI/SDAI response was evaluated. <h3>Results</h3> Of the 519 pts treated with TCZ, 217 early TCZ responders (DAS28&lt;2.6) completed week 16 (ITT1), 213 partial responder to TCZ entered a 2nd TCZ period (ITT-TCZ2). Except for RA activity, baseline data were relatively balanced. Baseline RA activity was lower in the ITT1 than in the ITT-TCZ2 set (mean DAS28 ± SD: 5.4±1.0 vs. 6.0±0.9). At week 16, high rates for low CDAI/SDAI (about 90%) and CDAI/SDAI remission (about 40%) were seen in early TCZ responders. In partial TCZ responders, mean DAS28 and clinical response continued to improve under continued TCZ treatment throughout week 32. Of the 213 pts who partially responded to TCZ at week 16, 54.9% achieved DAS28&lt;2.6 at week 32. The benefit of continued TCZ therapy became distinctly more pronounced in higher levels of response, eg, ACR70 response increased from 8.5% at week 16 to 34.3% at week 32, low CDAI from 27.2% to 59.2%, and CDAI/SDAI remission from 0% to 19–22%. <h3>Conclusions</h3> Early responders to TCZ also achieved high ACR response rates as well as CDAI/SDAI remission rates at week 16. Initial partial responders to TCZ at week 16 benefited from continuous TCZ therapy beyond week 16 and provide further evidence that sufficient initial treatment substantially reduce the need of subsequent biologic therapy. <h3>Disclosure of Interest</h3> T. Dörner: None declared, G.-R. Burmester Grant/research support from: AbbVie, Pfizer, UCB, Roche, Consultant for: AbbVie, BMS, Novartis, Medimmune, MSD, Pfizer, UCB, Roche, Speakers bureau: AbbVie, BMS, Novartis, MSD, Pfizer, UCB, Roche, H.-P. Tony Consultant for: AbbVie, Celgene, Chugai, Janssen, Lilly, MSD, Roche, Speakers bureau: AbbVie, Chugai, Roche, C. Iking-Konert: None declared, J. Kaufmann: None declared, P. Kästner: None declared, H. Kellner: None declared, R. Kurthen: None declared, S. Wagner: None declared, M. Peters Employee of: Roche Pharma AG, H. Schulze-Koops Consultant for: Roche