Less than half of patients with AS remain on first TNF inhibitor after 5 years
Only 46% of patients with ankylosing spondylitis remain on their first TNF inhibitor after 5 years, with one-third ending up with no anti-rheumatic treatment after this time, according to data published in Arthritis Research & Therapy.
“A substantial number of observational studies have described TNF [inhibitor] drug retention in AS from various perspectives, searching for predictors for remaining on treatment, and comparing retention rates in different subgroups,” Ulf Lindström, MD, PhD, of the Karolinska Institute in Stockholm, and colleagues wrote. “These long-term observational data describe a somewhat different picture than that of the [randomized controlled trials], suggesting that 1 year after starting a first TNF [inhibitor] around 80% remain on this treatment.”
“Taken together, reports of this type underscore the need for a better understanding of the somewhat contradictory evidence that patients with AS have high response rates to TNF [inhibitor], a low likelihood of successful termination of the treatment, and yet a limited drug retention,” they added.
To analyze 5-year treatment patterns and trajectories of patients with AS who start their first TNF inhibitor, Lindström and colleagues retrieved data from the national Swedish Rheumatology Quality register. According to the researchers, the register features an estimated coverage of 86% for patients with spondyloarthritis who are treated with biological DMARDs in Sweden. In all, 2,590 patients with AS who started their first TNF inhibitor from 2006 to 2015 were identified. The researchers followed these patients until Dec. 31, 2015.
During this time, the researchers recorded all changes in anti-rheumatic treatment. In addition, data were complemented with data on prescribed subcutaneous TNF inhibitors collected from pharmacies during each year.
According to the researchers, 74% of identified patients remained on their first TNF inhibitor after 1 year. However, that number dropped to 46% after 5 years. At that time, 63% were still receiving anti-rheumatic treatment with any biologic, and 30% were receiving no rheumatic treatment at all. During the 5 years after discontinuing the first TNF inhibitor, 46% switched directly to a second. However, drug retention rates for the second and third TNF inhibitors were successively shorter compared with the first.
Patients who remained with their first subcutaneous TNF inhibitor gradually reduced their dose, to the point that, in the fifth year of treatment, 66% had collected 75% or more of the defined annual daily doses.
“A TNF [inhibitor is the standard therapy for patients with active AS,” Lindström and colleagues wrote. “It is therefore noteworthy that, while 54% of patients will have discontinued their first TNF [inhibitor] within 5 years, 63% are still treated with a biologic. Further, patients who do remain on a TNF [inhibitor] treatment appear to be able to reduce the dose over time, which may have vast implications for health economic evaluations of biologics in AS.”
They added that “these findings also highlight the need for thorough follow-ups to target patients with AS who are non-responsive to TNF [inhibitor], and to determine predictors for such non-response, as well as alternative treatment options.” – by Jason Laday
Disclosures: Lindström reports no relevant financial disclosures. Please see the full study for additional authors’ disclosures.