The impact of apremilast on inflammatory and structural changes in psoriatic arthritis (PsA) can be better understood through magnetic resonance imaging (MRI), according to a recent study presented at the European Congress of Rheumatology (EULAR) 2023.
The data came from the MOSAIC phase 4, multicentre, single-arm, open-label study, in which the researchers used MRI to examine the effect of the oral immunomodulating phosphodiesterase-4 inhibitor apremilast on inflammation in patients with active PsA.
MOSAIC was the first trial to use MRI to assess inflammation in peripheral joints and entheses instead of traditional X-ray methods. Participants received oral apremilast 30 mg daily, either as monotherapy or in combination with stable methotrexate. Treatment continued for 48 weeks and individuals had an MRI scan of the hand performed at baseline and at Weeks 24 and 48.
Researchers set the primary endpoint as the change from baseline in the composite score of hand bone marrow oedema, synovitis and tenosynovitis in fingers two to five, assessed by the PsA MRI Score (PsAMRIS) at Week 24, and for which a negative change reflects disease improvements.
In addition, a total inflammation score, which comprised of bone marrow oedema, synovitis, tenosynovitis and periarticular inflammation in fingers, was also assessed. The team also considered disease activity with the clinical disease activity index for psoriatic arthritis (cDAPSA), which is lowered as disease activity reduces.
Apremilast and inflammatory changes
MOSAIC enrolled 122 patients who received apremilast. The mean age was 47 years (55% women) and the mean duration of PsA was 1.9 years. Some 98 patients provided evaluable data for the primary endpoint.
The least-squares mean change from baseline in the composite inflammation score of bone marrow oedema, synovitis, and tenosynovitis assessed by PsAMRIS was -2.32 at Week 24 and -2.91 at Week 48.
Significant improvements from baseline were also seen in total inflammation scores for those taking apremilast, together with a reduction in cDAPSA score. In addition, no significant structural progression was observed.
The researchers suggested their findings highlighted the value of using MRI and PsAMRIS as measures of disease activity change following PsA treatments.