At 12 weeks, 77% of psoriasis patients treated with risankizumab showed a 90% or greater reduction in Psoriasis Area and Severity Index (PASI) score, compared with 40% of ustekinumab patients, in a phase II randomized trial.
The results were published April 19 in the New England Journal of Medicine.
Ustekinumab (Stelara), approved by the Food and Drug Administration in 2009, blocks interleukin-12 and interleukin-23 and has demonstrated effectiveness in psoriasis patients. However, the humanized IgG1 monoclonal antibody risankizumab goes farther and “selectively inhibits interleukin-23 by specifically targeting p19,” wrote Kim A. Papp, MD, PhD, of K. Papp Clinical Research and Probity Medical Research, Waterloo, Ont., and associates (N. Engl. J. Med. 2017;376:1551-60. doi: 10.1056/NEJMoa1607017).
To compare clinical response and safety, the researchers enrolled 166 adults aged 18-75 years with moderate to severe plaque psoriasis, in the phase II study. Patients were randomized to subcutaneous injections of risankizumab at one of three doses, or ustekinumab at one of two doses. Risankizumab patients received a single 18-mg dose at week 0, or 90-mg or 180-mg doses at weeks 0, 4, and 16. Ustekinumab patients weighing 100 kg or less received 45 mg at weeks 0, 4, and 16; those weighing more than 100 kg received 90 mg at weeks 0, 4, and 16. Demographics were similar among the treatment groups.
The primary end point was a 90% or greater reduction in the PASI score at week 12, compared with baseline.
In pooled results of the risankizumab 90-mg and 180-mg groups, 77% of patients achieved a PASI 90 at 12 weeks (73% of the 90-mg group and 81% of the 180-mg group), vs. 40% of ustekinumab patients (P less than .001). Complete clearance of lesions (PASI 100) occurred among risankizumab patients in 14% of the 18-mg group, 41% of the 90-mg group, and 48% of the 180-mg group, compared with 18% of the ustekinumab group.
Among risankizumab patients, the rates of adverse events through 48 weeks were 81% in the 180-mg group, 80% in the 90-mg group, and 69% in the 180-mg group, compared with 72% in those on ustekinumab, with nasopharyngitis the most commonly reported adverse event in all the treatment groups. The rates of serious adverse events were 12% and 15% among those in the 18-mg and 90-mg risankizumab groups, respectively; 0% among those on the 180-mg dose, and 8% among those on ustekinumab.
The study was not large or long enough to provide conclusive safety data on risankizumab, and additional studies are needed to review psoriasis lesions over a longer time period and include both placebo and active comparators, researchers noted. However, the results suggest that “the selective blockade of interleukin-23 through the inhibition of the p19 subunit rather than p40 provides a more complete inhibition of interleukin-23 activity, potentially resulting in a greater efficacy in the treatment of plaque psoriasis at the doses used,” they said.
The study was supported by Boehringer Ingelheim. Several study coauthors, including lead author Dr. Papp, disclosed relationships with Boehringer Ingelheim and other companies. Several authors are Boehringer Ingelheim employees.