High TNF inhibitor retention rate in SpA patients
medwireNews: Researchers have found that the long-term retention rate for a first tumor necrosis factor (TNF) inhibitor is favorable in patients with spondyloarthritis (SpA).
In unadjusted analyses of data from 1077 patients in the Hellenic Registry of Biologic Therapies, an estimated 60% of patients were still taking their first TNF inhibitor 5 years later, while the 10-year retention rate was 49%.
The patients started taking their first TNF inhibitor between 2004 and 2014, with the majority, at 61%, receiving infliximab, and a total of 404 (37.5%) discontinued treatment during a follow-up of 4288 patient–years. Most (87%) of these discontinuations occurred in the first 5 years and mainly as a result of treatment inefficacy (43%), followed by adverse events (39%), the most frequent of which were infusion/injection reactions.
The researchers Prodromos Sidiropoulos (University of Crete Medical School, Heraklion, Greece) and colleagues note that the 561 patients with ankylosing spondylitis had superior rates of TNF inhibitor retention compared with the 375 with psoriatic arthritis and the 108 with undifferentiated SpA. The corresponding 5-year rates were 63% versus 59% and 49% and the 10-year rates were 55% versus 42% and 38%. The differences in drug survival times between patients with ankylosing spondylitis and those with psoriatic arthritis and undifferentiated SpA reached significance after 2.5 years and 7.0 years, respectively, they add.
Patients without versus with peripheral arthritis also had longer drug retention, particularly those with isolated axial disease, and multivariate analysis showed that patients with peripheral disease were 47% more likely to discontinue treatment over the 10-year period than those without peripheral disease.
Other significant factors influencing drug survival included sex, with men 32% less likely to discontinue treatment over the 10 years of treatment than women, and methotrexate co-therapy, which reduced the likelihood of discontinuation by 31%, while the use of etanercept, compared with a monoclonal antibody TNF inhibitor, increased the likelihood of discontinuation by 56%.
“Most interestingly, the strongest independent predictor for long-term drug survival was achievement of a major response in axial or peripheral disease during the first year,” the researchers point out.
They found that after adjusting for baseline variables, patients with axial disease who achieved inactive disease according to Ankylosing Spondylitis Disease Activity Score using C-reactive protein (ASDAS-CRP) or a 50% improvement in Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score within the first year of treatment were a respective 33% and 49% less likely to discontinue treatment than other patients.
Similarly, patients with peripheral disease who were in a state of remission according to Disease Activity Score at 28 joints (DAS28) within the first year of treatment were 35% less likely to discontinue treatment than others. Similar results were seen for patients achieving a EULAR good response and at least a 70% improvement in ACR criteria.
“To our knowledge, we are the first to report that clinical variables quantifiable early in the treatment course, such as ASDAS-CRP inactive disease state and DAS28-remission state, could predict a 2- to 3.5-fold higher chance of a 10-year drug survival in everyday clinical practice,” say Sidiropoulos and co-authors.
They conclude in The Journal of Rheumatology: “We thus support close disease activity monitoring as a valuable tool to predict long-term outcomes.”
By Lucy Piper
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