IL-17 Inhibitors In Non-Radiographic Axial SpA Save

This meeting sees new data on using anti-IL-17 agents in non-radiographic axial SpA. Up until now these patients have only had TNF inhibitors available, so data about the efficacy of IL17 inhibitors is really important.

We get to see new secukinumab (Late breaking abstract 21) 16 week data of their 555 patient trial with loading & no loading of 150mg of secukinumab versus placebo (1:1:1). Inclusion criteria are very important in this disease, as previous trials have been substantially affected by inclusion criteria, think poor response of adalimumab in ABILITY-1. Included patients had to meet the ASAS criteria and have an abnormal CRP or MRI. The primary endpoint was ASAS40 in TNF naïve patients at 16 weeks. Importantly 89-90% of patients were TNF inhibitor naïve and they had had their back pain for greater than 8 years. At week 16 42% of secukinumab patients met the primary endpoint versus 29% in the placebo group. Safety was consistent with previous secukinumab trials. 

We also get to see the ixekizumab (Plenary Session III, abstract 2729) 52 week data. Again, patients had to meet the ASAS criteria and also have an abnormal CRP or MRI and have an inadequate response to NSAIDs. Patients had had greater than 10 years of symptoms and a mean of 3-4 years since diagnosis. Patients were randomised (1:1:1) to placebo, 80mg every 2 weeks or 80mg every 4 weeks. The primary endpoint was ASAS40 at week 16 and week 52. At 16 weeks in the ITT population ASAS40 was 20%:34%:41% in placebo:Q4W:Q2W, and then at week 52 the ITT population ASAS40 was 14%:29%:32% in placebo:Q4W:Q2W.

It is very clear that the devil is in the detail when thinking about nr-axSpA and treatment response and the details that are important are CRP and MRI positivity, disease duration and previous biologic use. In nr-axSpA we have seen trials that have patients with short disease duration, a high proportion of positive CRP and MRI (or both even) and minimal previous biologic use have shown the best response. Therefore, comparisons between trials of different agents is much more challenging to try to get an idea of comparable efficacy. The take home is that anti-IL17 agents are effective in this condition but picking your patients carefully is likely to see a greater proportion responding favourably.