Early Predictors of Poor Long-Term Treatment Response in Spondyloarthritis

Determining which patients are unlikely to respond to therapy early on may help reduce unnecessary treatment and contain costs.

Patients being treated with certolizumab pegol (CZP) for psoriatic arthritis (PsA) or axial spondyloarthritis (SpA) are unlikely to achieve inactive disease if they exhibit poor response to therapy within the first 12 weeks of treatment, according to study results published in Arthritis Care & Research.1

Current recommendations for SpA advise treating to a target of clinical remission or inactive disease. According to these recommendations, SpA treatment regimens should be given up to 6 months to achieve the treatment targets, and therapy should be modified if no clinical response is evident by 3 months.2

Determining which patients are unlikely to respond to therapy early on — known as negative predictability — may help reduce unnecessary treatment and contain costs. Until recently, however, studies evaluating negative predictability in the treatment of axial SpA and PsA have been lacking.

Researchers, led by Désirée van der Heijde, MD, PhD, from Leiden University Medical Center in The Netherlands, examined the relationship between lack of treatment response at 12 weeks and clinical outcomes at 48 weeks in patients treated with CZP for axial SpA and PsA.

Data from patients treated with CZP in the RAPID-axSpA and RAPID-PsA trials — phase 3 studies comparing CZP vs placebo in axial SpA and PsA, respectively — were used in the study analysis.

The treatment target for axial SpA was inactive disease as measured by Ankylosing Spondylitis Disease Activity Score (ASDAS) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The treatment target for PsA was minimal disease activity as measured by Disease Activity Score in 28 joints using the CRP level (DAS28-CRP).

None of the 21 patients with axial SpA with high disease activity at 12 weeks attained inactive disease by 48 weeks. However, inactive disease was maintained at 48 weeks in the majority (68%) of the 50 patients with axial SpA with inactive disease at 12 weeks. Similar results were observed when BASDAI was used to measure disease activity.

In patients with PsA, 0% of 26 patients with very high DAS28-CRP disease activity at 12 weeks achieved minimal disease activity at 48 weeks. In contrast, 73% of 78 patients with DAS28-CRP minimal disease activity at 12 weeks maintained this disease state at 48 weeks.

Summary and Clinical Applicability

Current recommendations for SpA and PsA treatment suggest changing the treatment regimen if patients do not exhibit treatment response within the first 12 weeks. However, data on early predictors of poor treatment response in these populations were lacking until recently. Researchers found that in patients treated with CZP for axial SpA and PsA, patients with very high disease activity at 12 weeks were unlikely to achieve inactive disease at 48 weeks.

Dr van der Heijde told Rheumatology Advisor that negative predictability is a stronger indicator of outcomes than positive predictability, which relates to predicting whether the patient will achieve the intended outcome with continued treatment. If negative predictability for axial SpA and PsA treatment is “applied in clinical practice, risks of adverse events can be reduced and costs saved,” she said.

However, Dr van der Heijde indicated that further research is needed to confirm their findings. “The effect of implementing the findings in a strategy trial could add information on the true impact in clinical practice and the effect on outcome (efficacy, safety and costs),” she said.

Limitations and Disclosures

DAS28-CRP and BASDAI thresholds for defining disease activity have not been validated the axial SpA and PsA populations.

Disclosures: This study was funded by UCB Pharma. Dr van der Heijde has received fees from AbbVie, Amgen, Astellas, AstraZeneca, BMS, Celgene, Daiichi, Eli Lilly, Galapagos, Merck, Novartis, Pfizer, Roche, Sanofi-Aventis, and UCB Pharma. She is also the Director of Imaging Rheumatology BV.

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1. van der Heijde D, Deodhar A, Fleischmann R, et al. Early disease activity or clinical response as predictors of long-term outcomes with certolizumab pegol in axial spondyloarthritis or psoriatic arthritis [published online October 1, 2016]. Arthritis Care Res (Hoboken). doi:10.1002/acr.23092

2. Smolen JS, Braun J, Dougados M, et al. Treating spondyloarthritis, including ankylosing spondylitis and psoriatic arthritis, to target: recommendations of an international task force. Ann Rheum Dis. 2014;73(1):6-16. doi:10.1136/annrheumdis-2013-203419