medwireNews: The phase 3 POSTURE trial has demonstrated no clinical benefit of apremilast for patients with active ankylosing spondylitis (AS) and no prior exposure to biologic agents.
The primary findings from this trial have previously been posted on ClinicalTrials.gov, and the full results, with 2-years of follow-up, are now published in The Journal of Rheumatology.
POSTURE (also known as AS-001) included 490 patients from 88 centers across North America, Europe, Australia, South Africa, and Russia who were randomly assigned to receive oral apremilast 20 mg or 30 mg twice daily or to receive placebo.
Participants in the apremilast 20 mg and placebo groups with an inadequate response (without a ≥20% or ≥1 unit improvement from baseline in at least two of the ASAS20 response criteria) switched to the higher dose of the phosphodiesterase inhibitor at week 16, and all patients remaining in the placebo group at week 24 switched to apremilast 30 mg.
At week 16, a comparable proportion of participants treated with apremilast 20 mg or 30 mg versus placebo achieved the primary endpoint of an ASAS20 response, at rates of 35% and 33% versus 37%, respectively.
Peter Taylor (University of Oxford, UK) and co-investigators say that ASAS20 response rates were also “generally similar” in the three groups at the 24-week follow-up, and there were no significant differences in the average change from baseline in BASFI, BASDAI, and quality of life scores at this timepoint among patients treated with apremilast 30 mg versus placebo.
In the subset of 92 participants with radiographic progression data, average changes in mSASSS from baseline to the 2-year follow-up were 0.98, 0.57, and 0.83 points for participants initially assigned to apremilast 20 mg, apremilast 30 mg, and placebo, respectively. The corresponding proportions of patients with no radiographic progression (change in mSASSS <0 points) over this period were 67.3%, 75.2%, and 70.7%.
Taylor and team say that initial radiologic assessments at investigators’ meetings during the study suggested “modest improvement” on rates of radiographic progression over 2 years with apremilast treatment. However, they note that a post-hoc analysis using the OASIS database as a historic comparison group found no reduction in radiographic progression with apremilast versus standard care.
The “effects [of apremilast] on radiographic progression could not be accurately determined […] but are unlikely due to lack of effect on clinical disease activity,” write the researchers.
They say that the safety results “were consistent with the known safety profile of apremilast in other patient populations, including psoriasis and psoriatic arthritis.”
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