IL-23 Inhibition in Axial Disease and the Pipeline
Is the chapter on IL-23 inhibitors closed for axSpA? Aside from a possible role for axial disease in psoriatic arthritis (PsA), it likely is, Dr. Ruderman said, pointing to the phase 2 randomized, double-blind, placebo-controlled study of tildrakizumab in patients with AS that was terminated at week 24 after the drug showed no difference in efficacy from placebo.
Dr. Kavanaugh agreed. “This adds to the data on risankizumab and ustekinumab in studies done properly in AS,” he said. “There’s no benefit.”
The “real issue” still to be determined, said Dr. Ruderman, “is what is the role of IL-23 inhibitors in patients with axial PsA?”
A post-hoc analysis of data from the SELECT PsA 1 and 2 trials, published in 2023, showed greater improvement in the overall Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score in patients with axial disease who received 15 mg upadacitinib (Rinvoq), compared with placebo.
“It suggests there’s improvement in the patients with axial PsA as defined [by a high BASDAI score], but they didn’t compare this with patients without axial disease … it’s muddy,” Dr. Ruderman said. Other research that’s underway should provide clarity, Dr. Kavanaugh said.
The pipeline for new treatments for SpA, including axSpA, is focused on new biologics targeting the IL-17 pathways, as well as a fair number of targeted synthetics, Dr. Ruderman said. “What will be interesting to me is what happens with the TYK2 inhibitors … because one of the postulated mechanisms is that the IL-23 signals through TYK-2,” he said. “So if that’s the mechanism, will they really help our patients with axial disease? We need the trials to find out.”
The intravenous formulation of secukinumab, approved in 2023 for AS, nr-axSpA, and PsA, is a “nice addition to our armamentarium, Dr. Ruderman noted in his 2023 review. “For years, a patient doing well on an IL-17 inhibitor for their axial disease or their psoriatic disease would hit Medicare age and suddenly couldn’t afford subcutaneous administration, and we had to switch them over to an IV-TNF inhibitor,” he said. “Now we have an IV IL-17 inhibitor.”