Background

Psoriatic arthritis (PsA) is a destructive disease that leads to a change in the joint and entheseal architecture.

Objective

This study aimed to ascertain the effect of secukinumab on erosion and enthesophyte progression in PsA by high-resolution peripheral quantitative computed tomography (HR-pQCT).

Methods

This was a one-year double-blind, randomized, placebo-controlled trial (NCT0362386740). Patients with erosion in the metacarpophalangeal joints (MCPJ) 2-4 were randomised in a 1:1 ratio to either the secukinumab or placebo group. HR-pQCT of the MCPJ 2-4 were performed at baseline, week 24 and 1-year. Progression of enthesiophyte were defined as changes in volume exceeding smallest detectable change (SDC) (0.12mm³) or the identification of any new enthesophyte. Partial repair of erosion was defined as a reduction in erosion volume greater than SDC (0.1mm³).

Results

Forty patients (age: 51.9±13.4 years, 20 [50%] male, disease duration: 4.7±6.7years) were recruited. Thirty-four patients who completed study treatment were included in the per-protocol analysis. Patients in the secukinumab group had a greater improvement in clinical disease activity compared to the placebo group. At baseline, 44 and 61 erosions were identified in the secukinumab and placebo groups respectively. After one year, a significant difference was observed in the change in erosion volume between the two groups. (Figure-1A). Fewer patients developed new erosions in the secukinumab group (one erosion in one patient) compared to the placebo group (six-erosions in five-patients) (p=0.078) (Figure-1B). A higher proportion of pre-existing erosion in secukinumab exhibited partial erosion healing when compared to those in the placebo group (51% vs 30%, p=0.029) (Figure-1C). Using generalized estimated equation (GEE), the OR for erosion regression in the secukinumab group was 2.82 (95% CI: 1.11-7.15, p=0.029). Regarding enthesiophyte, a total of 25-enthesiophytes were identified in both the secukinumab and placebo groups at baseline. After one year, a significant difference was observed in the change in enthesophyte volume between the two groups (Figure-1D). One and 6 new enthesiophytes were identified in the secukinumab group and placebo group respectively (Figure-1E). The proportion of enthesiophytes with progression tended to be higher in the placebo group compared to the secukinumab group (40% vs 16%, p=0.114) (Figure-1F). The GEE analysis showed that the OR for enthesiophyte progression in the secukinumab group was 0.26 (95% CI: 0.078-0.87, p=0.029).

Conclusion

Secukinumab appears to have a potential benefit in preventing enthesophyte progression and facilitating partial erosion repair in PsA.

Figure 1. Changes in erosion and enthesophyte parameters by HR-pQCT.

* denotes p<0.05 comparing changes between the two groups over a period of one year.

A, changes in erosion volume between the two groups; B, % of patients with new erosion identified at week 24 and week 48; C, percentages (%) of pre-existing erosion with partial healing at week 24 and week 48; D, change in enthesiophyte volume between 2 groups; E, % of patients with new enthesiophyte identified at week 24 and week 48; F, % of pre-existing enthesiophyte with progression at week 24 and week 48