Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.

Probability to Achieve Low Disease Activity at 52 Weeks in Rheumatoid Arthritis (RA) Patients Treated with Certolizumab Pegol (CZP) Depends On Time to and Level of Initial Response

van der Heijde¹, Désirée M.F.M., Schiff², M., Keystone³, Edward C., Landewe⁴, R., Kvien⁵, T.K., Curtis⁶, J. R., Khanna⁷, D.

Leiden University Medical Center, Leiden, Netherlands
Baylor Research Institute, Dallas, TX
Univ of Colorado School of Medicine, Denver, CO
Professor of Medicine/University of Toronto, Toronto, ON
Maastricht Univ Medical Ctr, Maastricht, Netherlands
Diakonhjemmet Hospital, Oslo, Norway
Univ of Alabama at Birmingham, Birmingham, AL
UCLA, Los Angeles, CA
UCB, Brussels, Belgium
David Geffen School of Medicine at UCLA, Los Angeles, CA

Purpose:

The relationship between an early response to biologic therapy and longer-term clinical outcomes has not been well characterized. We conducted a posthoc analysis to determine the relationship between initial improvement in DAS28(ESR) score within 12 weeks (wks) and probability to achieve low disease activity (LDA; DAS28 <=3.2) at Wk 52 in RA patients (pts) treated with CZP.

Methods:

The proportion of pts treated with CZP (200 or 400 mg) + MTX who had LDA at Wk 52 was assessed among pts who achieved or failed to achieve various DAS28 responses (ie, DAS28 decrease from baseline [BL] <0.3, 0.6, 0.9, 1.2, 1.5 and 1.8 units) by Wks 1, 2, 4, 6, 8, 10 or 12. Results were analyzed for the ITT (LOCF) population. Pts with non-imputable missing data during the first 12 wks of treatment were excluded from the analysis.

Results:

Of the 783 pts randomized to CZP + MTX, 98% had DAS28 >5.1 at BL; 30% achieved LDA by Wk 52. By Wk 12, 98%, 87% and 74% of CZP-treated pts had DAS28 decreases from BL >=0.3, >=1.2, and >=1.8, respectively. CZP-treated pts who improved their DAS from BL by <0.3 up to Wk 6 (N=41) had 0% probability of achieving LDA at Wk 52 (Table). Similarly, pts who improved their DAS from BL by <0.6 or 0.9 up to Wk 10 (N=45 and N=76, respectively) had 0% chance to achieve LDA at Wk 52. Pts who had a change of <0.3 at Wk 4, <0.6 and 0.9 at Wk 6, <1.2 at Wk 8, or <1.5 and 1.8 at Wk 12 had a <5% probability of achieving LDA at Wk 52 (bolded rows of Table).

Conclusion:

Long-term response to CZP can be estimated early in the course of treatment. The majority of RA pts respond within the first 12 wks of CZP treatment. Furthermore, the probability of not achieving LDA at Wk 52 can be predicted by a combination of the change in DAS28 from BL and the time at which DAS28 was assessed after starting CZP treatment.

Table. Percentage* of CZP-treated pts with LDA at Wk 52 out of those who failed to achieve DAS decreases up to wk of follow-up for the first 12 wks

	Wk
DAS28 Change	1	2	4	6	8	10	12
<0.3	19.5	11.6	3.2	0	0	0	0
	(N=220)	(N=112)	(N=63)	(N=41)	(N=27)	(N=19)	(N=14)
<0.6	21.0	14.8	7.1	2.5	3.2	0	0
	(N=352)	(N=209)	(N=126)	(N=79)	(N=63)	(N=45)	(N=34)
<0.9	22.8	17.0	8.9	4.2	2.8	0	0
	(N=457)	(N=317)	(N=202)	(N=144)	(N=106)	(N=76)	(N=67)
<1.2	24.7	19.1	12.8	7.5	4.5	3.1	1.0
	(N=546)	(N=418)	(N=288)	(N=214)	(N=157)	(N=129)	(N=103)
<1.5	26.1	21.5	16.5	11.7	7.2	5.5	2.1
	(N=605)	(N=492)	(N=369)	(N=281)	(N=221)	(N=182)	(N=145)
<1.8	27.9	24.4	17.4	12.3	9.5	7.3	4.9
	(N=656)	(N=573)	(N=448)	(N=357)	(N=294)	(N=245)	(N=206)
* N numbers are denominators for % calculations and are the number of pts not achieving the DAS28 change threshold at the wk presented.

To cite this abstract, please use the following information:
van der Heijde, Désirée M.F.M., Schiff, M., Keystone, Edward C., Landewe, R., Kvien, T.K., Curtis, J. R., et al; Probability to Achieve Low Disease Activity at 52 Weeks in Rheumatoid Arthritis (RA) Patients Treated with Certolizumab Pegol (CZP) Depends On Time to and Level of Initial Response [abstract]. Arthritis Rheum 2009;60 Suppl 10 :992
DOI: 10.1002/art.26069

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