Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.

Tasocitinib (CP-690,550), an Orally Available Selective Janus Kinase Inhibitor, Exhibits Sustained Safety and Efficacy in the Treatment of Rheumatoid Arthritis over 24 Months.

A. Connell,  Carol, Riese,  Richard, Wood,  Susan, Bradley,  John, H. Zwillich,  Samuel


Tasocitinib (CP-690,550) is an orally available, small molecule Janus kinase inhibitor that has previously demonstrated efficacy and acceptable safety in patients with active rheumatoid arthritis (RA) in randomized studies of up to 24 weeks of treatment. Here we report the safety and tolerability of tasocitinib and the durability of response beyond 24 weeks in patients with RA.


In this Phase 2/3, open label study of 1070 patients who had participated in a prior randomized study of tasocitinib (PRST), treatment was initiated with either 5 or 10 mg tasocitinib twice daily. The baseline is that of the PRST for patients who enrolled within 14 days of PRST participation; if enrollment was >14 days after PRST participation, baseline was the start of this study. The primary endpoints were laboratory safety and adverse event (AE) reports. Secondary endpoints included ACR20, ACR50 and ACR70 response rates, Disease Activity Score using the erythrocyte sedimentation rate (DAS28-4 [ESR]), and the Health Assessment Questionnaire-Disability Index (HAQ-DI). Results are reported for all patients (ALL) and stratified according to those who completed Month 12 (M12) and Month 24 (M24) visits.


1070 patients were treated for a total duration of 1295.7 patient-years; median days of treatment were 518.5 (ALL, n=1070), 655.0 (M12, n=648), and 796.0 (M24, n=207). Seventy patients discontinued from the study due to AEs. A total of 929 treatment-related AEs (TRAEs) were reported; the most frequently reported classes of events were infections and infestations (197, 18.4%), gastrointestinal disorders (109, 10.2%), and investigations [laboratory] (79, 7.4%). 188 serious AEs (SAEs) were reported, of which 48 (25.5%) were considered possibly related to treatment. The most frequently reported class of SAEs was infections (34, 18.1%, 2.62/100 patient-years of tasocitinib treatment).

Mean DAS28-4(ESR) at baseline was 6.41 (ALL); at month 12, 3.70 (ALL) and at month 24, 3.55 (ALL). ACR20, ACR50, and ACR70 percent responders were similar through month 24 in all groups, as seen in Figure 1.

Figure 1.% responders for (a) ACR20, (b) ACR50, (c) ACR70 and (d) mean DAS28-4(ESR) score for patients initially treated with tasocitinib 5 or 10 mg BID.

Mean HAQ-DI scores were improved compared with baseline and remained consistent over time for ALL patients: 1.46 (baseline), 0.86 (Month 12), and 0.76 (Month 24) and M24 patients: 1.38 (baseline), 0.74 (Month 12), and 0.76 (Month 24).


Tasocitinib is effective in the long-term treatment of RA with a manageable safety profile. Efficacy is demonstrated by sustained improvement in ACR response rates, DAS28-4(ESR), and HAQ-DI over a 24-month period.

To cite this abstract, please use the following information:
A. Connell, Carol, Riese, Richard, Wood, Susan, Bradley, John, H. Zwillich, Samuel; Tasocitinib (CP-690,550), an Orally Available Selective Janus Kinase Inhibitor, Exhibits Sustained Safety and Efficacy in the Treatment of Rheumatoid Arthritis over 24 Months. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1129
DOI: 10.1002/art.28896

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