Effects of TNF-α inhibition versus secukinumab on active ultrasound-confirmed enthesitis in psoriatic arthritis

Abstract

Introduction:

Enthesitis is a hallmark of psoriatic disease, but its clinical assessment is problematic in terms of diagnostic sensitivity and overlap with other comorbid conditions. Ultrasound is a useful tool that can give a more detailed assessment of enthesitis. Research demonstrates that those with persistent ultrasound entheseal disease are at risk of progressive articular damage. With limited data to guide choice between biologic therapy for psoriatic arthritis (PsA) patients, we wanted to assess the response of ultrasound-confirmed enthesitis to different forms of biologic therapies and study its utility in making more informed decisions.

Methods:

This was an open label observational study including patients aged ⩾18 years, who fulfil the classification criteria for PSA (CASPAR) and were due to commence on their first biologic therapy. The primary outcome was the change in MAdrid Sonographic Enthesitis Index (MASEI) score at 16 weeks of treatment. The MASEI score was also modified to assess the active elementary lesions (ActiveMASEI).

Results:

In all, 80 PsA patients were enrolled with 75 patients completing the study [secukinumab n = 23 and tumour necrosis factor inhibitor (TNFi) n = 52]. The mean reduction in MASEI score after 16 weeks of treatment was 3.42 with TNFi versus 1.74 with secukinumab ( p = 0.097). There was a significant difference in the change in the MASEIActive score for TNFi versus secukinumab (4.37 versus 2.26; p = 0.030) and this difference was more pronounced when only power Doppler signal within 2 mm of the enthesis insertion was included (4.37 versus 2.00; p = 0.007). Clinical outcomes were similar for both classes of biologic apart from a significant reduction in regards to the Dermatology Life Quality Index and Psoriasis Area and Severity Index score with secukinumab versus TNFi.

Conclusions:

We have for the first time compared the effect of ultrasound-confirmed enthesitis between different forms of biologic therapies for PsA. We have seen an overall improvement in entheseal scores for both classes of medications and demonstrated a larger reduction in active entheseal disease for TNFi versus secukinumab that merits further exploration.

Plain language summary

Introduction: An enthesis is the point at which ligament and tendon insert into the bone and enthesitis is the inflammation at these sites causing pain and reduced function.Enthesitis is particularly common in patients with psoriatic arthritis and it has been shown to be important in the development, diagnosis and prognosis of the condition. Clinical examination has limitations and imaging techniques like ultrasound have been proven to give a more detailed assessment of enthesitis potentially revealing clues to the condition itself. In psoriatic arthritis, we do not have a good way of choosing between biologic therapies that can treat inflammation. With a better understanding of enthesitis and its response to various therapies, we may be able to make better decisions. We wanted to examine the extent of enthesitis within a group of psoriatic arthritis patients who were to commence on their first biologic therapy by examining them both with ultrasound and then with clinical examination.

Methods: We recruited 80 patients in which their consultant rheumatologist had decided to commence them on therapy. We carried out an ultrasound assessment of six entheseal sites as per an established assessment tool called the MAdrid Sonographic Enthesitis Index (MASEI). We then proceeded to take a history from the patients and examine all aspects of their joint disease just before they began their therapy. We repeated the ultrasound and clinical examination after 16 weeks of treatment without knowing what treatment they were on.

Results: In all, 75 patients completed the study and 23 of these were treated with secukinumab, a drug that targets interleukin-17a (IL-17i), an important protein in psoriatic disease and 52 patients were treated with medications that target tumour necrosis factor inhibitor (TNFi), another important inflammatory protein. Overall, we demonstrated a reduction in ultrasound scores for entheseal disease in those treated with both classes of medication. For the TNFi group, there was a larger improvement in scores compared with the IL-17i which was not significant for the primary focus of the study, the overall MASEI score. We have also demonstrated that there may be a larger improvement in TNFi response versus IL-17i when only counting the inflammatory disease component of the MASEI score. In terms of clinical results, the findings were broadly similar except that secukinumab was better at improving skin psoriasis.

Conclusion: Our work is the first with ultrasound to compare outcomes for enthesitis between classes of biologic therapy and should form the basis of future studies attempting to confirm these findings to make better decisions for those living with psoriatic arthritis.