Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

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


Achieving Minimal Disease Activity (MDA) Criteria with Anti-TNF Therapy in Psoriatic Arthritis Can Prevent Progressive Joint Damage

Coates,  Laura C., Helliwell,  Philip S.

Purpose:

Minimal disease activity (MDA) is defined by OMERACT as "that state of disease activity deemed a useful target of treatment by both the patient and physician, given current treatment possibilities and limitations" and criteria for MDA in psoriatic arthritis (PsA) have been developed. The aim was to investigate if achieving MDA can improve radiological outcome.

Methods:

The study was an analysis of most patients in the phase III infliximab studies. In both, patients with active PsA (>5 tender & swollen joints) who failed standard therapy (NSAIDs or DMARDs) were treated with infliximab 5mg/kg or placebo. In IMPACT1, patients were given double blind therapy for 16 weeks and open label treatment to week 94. In IMPACT2, patients were given double blind therapy for 24 weeks followed by open label treatment. Early escape was possible at week 16 for non-response.

Patients were classified as MDA if they fulfilled 5 of 7 from: tender joint count21; swollen joint count21; psoriasis activity and severity index21 or body surface area23; patient pain visual analogue score(VAS)215; patient global disease activity VAS220; health assessment questionnaire20.5; tender entheseal points21. Radiological progression was assessed using modified PsA Sharp-van der Heijde (S-vdH) scores for the hands and feet. All analysis is on an intention-to-treat basis.

Results:

In IMPACT1 full data were available for 63 patients. Of those receiving infliximab, 48% (15/31) achieved MDA at week 16 compared to 3% (1/32) on placebo (p<0.0001). At week 50, when all patients were treated with infliximab, 42% were in MDA. At week 50, 96% of those patients who achieved MDA showed no progression of radiological disease (increase in S-vdH score of 20), compared to 67% of those who did not achieve MDA (p=0.012). At week 98, 12/37 (30%) were in MDA. All patients who achieved MDA at week 98 showed no radiological progression, compared to 58% of those who did not achieve MDA (p=0.03).

In IMPACT2 data were available for 157 patients. Of those receiving infliximab, 52% (40/77) achieved MDA at week 24 compared to 21% (17/80) on placebo (p<0.001). At week 54, when all patients were on infliximab, 63 of 157 (40%) were in MDA. At week 54, 78% of those patients who achieved MDA showed no radiological progression, compared to 57% of those who did not achieve MDA (p=0.009). Cumulative probability plots of changes in S-vdH score through week 54 are shown. The curve for IMPACT2 patients consistently in MDA (at week 24 and 52) lies to the right of the control curve indicating less proportion of patients with radiographic progression and a smaller average amount of radiographic progression in MDA patients.

Conclusion:

Achieving MDA in PsA using effective therapy reduces ongoing radiological joint damage, even in a DMARD resistant cohort. The new MDA criteria could provide an objective target for treatment in trials and clinical practice.

To cite this abstract, please use the following information:
Coates, Laura C., Helliwell, Philip S.; Achieving Minimal Disease Activity (MDA) Criteria with Anti-TNF Therapy in Psoriatic Arthritis Can Prevent Progressive Joint Damage [abstract]. Arthritis Rheum 2009;60 Suppl 10 :2022
DOI: 10.1002/art.27094

Abstract Supplement

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