medwireNews: Most patients with axial spondyloarthritis (axSpA) who stop taking ixekizumab respond to the treatment when it is reintroduced following disease flare, analysis of COAST-Y data suggests.
“Expected or otherwise, patients sometimes pause or stop biologic medications, and clinicians and patients may have concerns about recapturing efficacy when drugs are restarted,” explain Robert Landewé, from Amsterdam Rheumatology Center in the Netherlands, and co-researchers.
They highlight: “The present findings may be of relevance to patients who may need temporary withdrawal of therapy due to pregnancy, relevant concomitant disease or surgery, for example.”
For the previously reported phase 3 COAST-Y trial, 741 patients with axSpA were treated with ixekizumab 80 mg every 2 or 4 weeks for 24 weeks, after which 155 had achieved remission (ASDAS <1.3 indicating inactive disease at least once at week 16 or 20 and <2.1 indicating low disease activity [LDA] at both visits) and were randomly assigned to continue treatment with the interleukin-17A inhibitor or switch to placebo for a further 40 weeks.
During this time, significantly more patients who continued treatment remained free of disease flare, defined as an ASDAS of at least 2.1 on two consecutive visits or less than 2.1 at both visits, than did those who stopped, at 83.3% versus 54.7%.
The current analysis examined data for 138 of these patients over a further 40 weeks (80 weeks from treatment withdrawal) and found that, among the 53 who discontinued ixekizumab treatment, 53% experienced disease flare. However, most (96%) regained ASDAS LDA by restarting open-label ixekizumab at the original dosing regimen. This occurred in 14% of patients before ixekizumab was restarted and in 82% within 16 weeks of restarting treatment.
ASDAS inactive disease was achieved by 71% of patients: before retreatment in 4%, within 16 weeks of treatment in 50%, and after 16 weeks in 18%.
“These data may provide further support to patients who require interruption in active therapy,” the researchers write in the Annals of the Rheumatic Diseases.
Among the 102 patients who continued ixekizumab treatment, 13 experienced disease flare. Of these, 92% regained LDA – 54% before retreatment, 15% within 16 weeks of retreatment, and 23% after 16 weeks. Inactive disease was seen in 38%, occurring mostly within 16 weeks of retreatment.
The researchers looked at possible predictors of flare and found that “patients with higher disease activity over time were more likely to experience a flare than those with consistently low disease activity,” as were those who stopped taking treatment.
They also note that longer symptom duration – of at least 5 years – was associated with disease flare in patients who stopped taking ixekizumab, “whereas this association was not observed in patients who continued [ixekizumab] treatment.”
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