AMSTERDAM – Phase 2 data with the IL-23 inhibitor risankizumab at week 24 were even more impressive than the week 16 data, showing that without any further dosing after week 16, all doses provided protection against radiographic progression relative to placebo at 24 weeks, according to data presented at the European Congress of Rheumatology.
In a video interview, first author Philip J. Mease, MD, a rheumatologist at Swedish Medical Center in Seattle, explained that it is not only the high rates of response to risankizumab but also the prolonged response that are attracting attention.
Risankizumab is among several monoclonal antibodies developed to target the p19 subunit of the proinflammatory cytokine IL-23. These drugs have already shown a high degree of efficacy for psoriasis, according to Dr. Mease. However, the new data with risankizumab confirm prolonged responses against a broad range of additional clinical targets specific to psoriatic arthritis, including bone destruction and enthesitis.
A prolonged response in patients treated with a single, relatively low dose of risankizumab is one of the intriguing findings. While three of the four active treatments arms received multiple infusions of 150 mg, the single-dose arm received only 75 mg of risankizumab once at baseline. At 16 weeks and 24 weeks, all arms, including the single-dose arm, met the primary endpoint of superiority to placebo for ACR20. At week 24, the single infusion of 75 mg was also providing significant benefit for several secondary endpoints, including radiographic progression.
However, the higher, more frequent doses did show greater efficacy overall. For example, patients in the arm with the most frequent dosing of risankizumab (every 4 weeks) and no dosing after week 16 continued to show significant improvement in enthesitis. A less frequent schedule of 150 mg risankizumab and the arm receiving a single dose of 75 mg risankizumab were not associated with a significant advantage over placebo for this endpoint.
Still, the prolonged responses at week 24 suggest that it may be possible to administer risankizumab at intervals that are less frequent than many other biologics.
So far, there “is nothing remarkable about safety,” Dr. Mease explained. A higher rate of infection relative to placebo was a treatment-emergent side effect in this study, but Dr. Mease said the drug is well tolerated.
Risankizumab is poised for evaluation in a phase 3 trial for psoriatic arthritis, and Dr. Mease was optimistic about its potential role, predicting that this, as well as other anti-IL23 p19 monoclonal antibodies, is likely to be an “important addition to our armamentarium.”
AbbVie and Boehringer Ingelheim funded the risankizumab study. Dr. Mease has received grant/research support from AbbVie and many other pharmaceutical companies. He also is a consultant to them and is on their speakers bureaus.
SOURCE: Mease P et al. Ann Rheum Dis. 2018;77(Suppl 2):200-1. Abstract OP0307