The results from a pair of clinical trials should help to take the guesswork out of starting and stopping the tumor necrosis factor inhibitor etanercept (Enbrel) in patients with nonradiographic axial spondyloarthritis (nr-axSpA). The trials were reported at the annual European Congress of Rheumatology, held online this year due to COVID-19.
Dr. Nigil Haroon
Optimal use of etanercept in this disease is still being defined, according to the investigators. Its effects, if any, when given very early in the disease course is unclear, and guidance is conflicting when it comes to stopping the drug after inactive disease is achieved.
In the Dutch randomized controlled PrevAS trial of 80 patients with suspected very early nr-axSpA, initiating etanercept instead of placebo did not significantly improve the odds of achieving a 20% improvement in Assessment of Spondyloarthritis International Society (ASAS 20) response criteria at week 16.
And in the multinational, open-label, phase 4 RE-EMBARK trial, three-quarters of the 119 patients with nr-axSpA who achieved inactive disease on etanercept and stopped the drug experienced a flare within 40 weeks. However, the majority were able to regain disease inactivity after restarting the drug.
Findings in context
“We all have some patients like this [PrevAS population] where we strongly believe they have axial spondyloarthritis but do not fully qualify,” Nigil Haroon MD, PhD, said in an interview. “From a clinical decision-making process, we may diagnose these patients with axial spondyloarthritis, but due to restrictions in access to medications, we have difficulty accessing biologic medications for them. Hence, this study has practical implications.”
“It has already been shown in other, much larger studies that, even in patients who satisfy the criteria of axial spondyloarthritis, those who are MRI and CRP [C-reactive protein] negative are unlikely to respond, so the results are not surprising,” commented Dr. Haroon, who is codirector of the spondylitis program at the University Health Network and associate professor of medicine and rheumatology at the University of Toronto.
Although intended to be a population with suspected very early disease, several of the PrevAS patients would have met ASAS criteria for the disease at baseline, Dr. Haroon cautioned. In addition, the small sample size precluded subgroup analyses.
“The overall conclusion should be, this is a negative study, rather than state there was a trend to better improvement on etanercept. Although there are practical implications, as mentioned, I don’t think this study, with the numbers and the results presented, will change clinical practice,” he said.
The question of stopping biologics in nr-axSpA was previously addressed in the ABILITY-3 randomized trial of adalimumab (Humira), which found that flares were significantly more common with stopping versus continuing the drug and only about half of patients were able to get back in remission by restarting the drug, according to Dr. Haroon.
However, the RE-EMBARK and ABILITY-3 studies differed in both design and patient population, he noted. For example, the mean disease duration was only about 2 years in the former study, compared with 7 years in the latter.
The initial 59% rate of attaining inactive disease on etanercept in RE-EMBARK was “impressive,” Dr. Haroon said, “but as this was an open-label study, higher values are expected.”
“The message in both studies is that stopping biologics completely is not a good idea as the majority of patients, 70%-75%, will relapse within a short period,” he concluded. “However, it should be kept in mind that these [RE-EMBARK] patients received biologic only for a short 24-week period. This study does not answer the question of whether nonradiographic axial spondyloarthritis patients with sustained inactive disease can be taken off biologics abruptly without a taper over time.”