MADRID – Trial results presented at the European Congress of Rheumatology for three anti–interleukin-17 receptor monoclonal antibodies under investigation for the treatment of axial spondyloarthritis (axSpA), including one for ankylosing spondylitis (AS), appear to support further clinical development and regulatory review to potentially join secukinumab (Cosentyx) and ixekizumab (Taltz) as the only IL-17 inhibitors to be licensed for rheumatic diseases.
Both netakimab and brodalumab (Siliq) achieved positive results in separate phase 3 trials for the treatment of axSpA, while new data from a phase 2b trial of bimekizumab was associated with improvement in the quality of life of patients with AS. Brodalumab is already approved by the Food and Drug Administration for treating moderate to severe plaque psoriasis.
The multinational, double-blind, phase 3 trial with netakimab, called the, randomized 228 patients with radiographic axSpA to either 120 mg of the experimental agent or placebo, each administered subcutaneously in weekly doses in the first 2 weeks and then every other week thereafter. The primary endpoint was a 40% improvement in Assessment of SpondyloArthritis International Society response criteria (ASAS40) at week 16.
A larger proportion of patients in the netakimab arm met the primary endpoint, compared with those in the placebo arm (40.4% vs. 2.63%, respectively; P less than .0001), reported Inna Gaydukova, MD, of Mechnikov North-Western State Medical University, St. Petersburg, Russia.
“Most of the secondary efficacy endpoints also showed a significant advantage for netakimab relative to placebo by week 4, and these advantages remained significant for the remainder of the study,” she said.
The one serious adverse event in the study occurred in the placebo arm. Although mild to moderate anemia and neutropenia were associated with treatment, the drug was well tolerated overall.
“We did observe a significant reduction in inflammatory activity in the spine with MRI at week 16,” Dr. Gaydukova added. Functional improvements in the experimental arm relative to the placebo arm were also observed, although Dr. Gaydukova acknowledged that longer trials are needed to show that these benefits are durable.
The results of a multinational, double-blind, phase 3with brodalumab proved similar to those with netakimab. Conducted in Taiwan, Japan, and South Korea, the trial randomized 159 patients to 210 mg of brodalumab or placebo administered subcutaneously. The therapies were administered on the same schedule as in the netakimab trial. The primary outcome was also the same.
At week 16, 43.8% of those on the experimental agent versus 24.1% of those randomized to placebo achieved ASAS40 (P = .018). As in the netakimab study, greater activity with brodalumab than placebo was also seen on several secondary outcomes, such as ASAS20 (67.5% vs. 41.8%).
“In a subgroup analysis, there was an advantage for brodalumab over placebo whether or not patients had prior experience with a TNF [tumor necrosis factor] inhibitor, regardless of baseline hs-CRP [high sensitivity C-reactive protein] level and independent of HLA type,” reported James Cheng-Chung Wei, MD, of Chung Shan Medical University Hospital, Taichung, Taiwan.
There were no significant differences in the types or rates of adverse events, including serious adverse events, in patients assigned to brodalumab relative to placebo. Suicide ideation, which has been associated with some biologics targeting other immunologic mediators, was evaluated but not seen.
“We think brodalumab has the potential to be a new therapeutic option in axSpA,” said Dr. Wei, who reported that studies in AS are also planned.