EXPERT ANALYSIS FROM RWCS 2018
MAUI, HAWAII (FRONTLINE MEDICAL NEWS) – How long do patients with ankylosing spondylitis need to be on a tumor necrosis factor (TNF) blocker in order to experience clinically meaningful inhibition of spinal x-ray progression?
At least 2 years, Orrin M. Troum, MD, said at the 2018 Rheumatology Winter Clinical Symposium.
He cited a study by the rheumatologists of the Swiss Clinical Quality Management Program which he considers one of the recent highlights in rheumatologic imaging.
The ongoing prospective observational study included 432 patients with ankylosing spondylitis followed for up to 10 years with spinal radiographic assessments every 2 years. Spinal radiographic progression was defined as an increase of 2 or more units on the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) in 2 years.
The mean increase in mSASSS was 0.9 units in 2 years. Prior use of a TNF inhibitor reduced the likelihood of progression by 50% in a multivariate analysis, observed Dr. Troum , a rheumatologist at the University of Southern California, Los Angeles, who is also in private practice in Santa Monica, Calif.
Responders to anti-TNF therapy as defined by an Ankylosing Spondylitis Disease Activity Score (ASDAS) of 2.1 or less at the beginning of a 2-year radiographic interval had a mean mSASSS progression of just 0.31 units in the next 2 years, compared with a 1.45-unit increase in nonresponders to anti-TNF therapy with an ASDAS score above 2.1.
Moreover, patients on anti-TNF therapy who achieved inactive disease status as defined by an ASDAS of 1.3 or less at the beginning of the next 2-year radiographic interval experienced essentially no radiographic progression during that interval, with a mean mSASSS increase of just 0.01 units as compared with a 0.52-unit increase in those with an ASDAS of 1.3-2.1. The inference, according to the investigators, is that the reduction in spinal x-ray progression associated with TNF inhibitor (TNFi) therapy was mediated by the biologic therapy’s inhibitory effect on disease activity.
“We present important clues concerning the period of time needed before the inhibitory effects can be objectified: around 2 years of continuous TNFi use, as there was no impact of TNFi treatment during a 2-year radiographic interval, while there was an effect if the treatment was started before this interval. … Our study suggests that [an ASDAS of 1.3 or less] might be an adequate target, if the goal of treatment is inhibition of further spinal radiographic damage in addition to control of signs and symptoms, ” according to the investigators ( Ann Rheum Dis. 2018 Jan;77:63-9 ).
Dr. Troum reported serving as a consultant to and/or research grant recipient from more than half a dozen pharmaceutical companies.