The Effect of Apremilast on Whole‑Body MRI in Psoriatic Arthritis

A new article, “Effect of apremilast on whole‑body magnetic resonance imaging of peripheral and axial inflammation in patients with psoriatic arthritis,” has been published in Annals of the Rheumatic Diseases. This study demonstrates how whole‑body MRI and advanced scoring systems can quantify apremilast’s impact on key musculoskeletal domains in PsA, and highlights the value of centralised, quantitative imaging strategies in clinical development.

“Effect of apremilast on whole‑body magnetic resonance imaging of peripheral and axial inflammation in patients with psoriatic arthritis”, Annals of the Rheumatic Diseases, 2026.

The study “Effect of apremilast on whole‑body magnetic resonance imaging of peripheral and axial inflammation in patients with psoriatic arthritis”, published in Annals of the Rheumatic Diseases, was conducted by Mikkel Østergaard, Robert G W Lambert, Walter P Maksymowych, Mikael Boesen, Michael R Bubb, Olga Kubassova, Guillermo Valenzuela, Stephen Colgan, Cynthia Deignan, Zhenwei Zhou and Philip J Mease. This international team of rheumatologists, radiologists and imaging scientists brings deep experience in psoriatic arthritis and advanced MRI, enabling rigorous acquisition, central image review and quantitative analysis across the study.

Psoriatic arthritis is a heterogeneous inflammatory disease, involving peripheral joints, entheses and, in many patients, the axial skeleton. Traditional clinical scores and regional imaging often fail to capture the true burden and distribution of inflammation or to track subtle treatment‑induced changes over time. This is particularly relevant in early disease, in multi‑domain phenotypes, and in studies of targeted therapies where differentiation may depend on sensitive, objective biomarkers.

Whole‑body MRI (WB‑MRI) provides a comprehensive, single‑examination view of both peripheral and axial structures, including joints and entheses. When combined with validated scoring systems, WB‑MRI can quantify inflammatory burden and its modification under therapy, supporting trial endpoints beyond conventional composite scores.

The newly published paper builds on the phase 4 MOSAIC study, a multicenter, single‑arm, open‑label trial evaluating apremilast 30 mg twice daily, with or without stable methotrexate, in adults with active psoriatic arthritis. Patients met CASPAR criteria, had active peripheral disease and were followed over 48 weeks with serial MRI.

Key design features included:

• Population: Adults with early psoriatic arthritis, active peripheral arthritis and optional axial involvement.
• Intervention: Apremilast 30 mg BID as monotherapy or in combination with methotrexate.
• Imaging schedule: Whole‑body MRI at baseline, week 24 and week 48, alongside dedicated axial MRI.
• Central reading: All scans read and adjudicated by two experienced readers, blinded to time point and clinical response, to ensure robust, unbiased assessments.

This framework allowed investigators to characterise apremilast’s effects on peripheral joints, entheses and axial inflammation across the whole body, rather than limiting observation to a few regions.

The study applied state‑of‑the‑art MRI scoring systems developed within OMERACT and international spondyloarthritis collaborations:

• MRI‑WIPE (OMERACT MRI Whole‑body Score for Inflammation in Peripheral Joints and Entheses)
  • Assesses 83 peripheral joints and 33 entheses in a single WB‑MRI examination.
  • Generates a total peripheral inflammation index, with separate indices for joint inflammation and enthesitis.
• CANDEN MRI scoring system for axial inflammation
  • Provides detailed, anatomy‑based scoring of spine inflammation, including vertebral bodies, posterior elements, corner and non‑corner lesions, and posterolateral structures.
• SPARCC scores (exploratory)
  • SPARCC spine and sacroiliac joint scores were used as additional axial indices in a subset with PsA spondylitis and significant inflammatory back pain.

This quantitative imaging framework complements previously published MOSAIC work using PsAMRIS and dynamic contrast‑enhanced MRI in the hands, and reflects a maturing toolkit for multi‑domain MRI in psoriatic arthritis.

Using MRI‑WIPE, the study showed that apremilast reduced MRI‑detected peripheral inflammatory burden across joints and entheses:

• The total peripheral inflammation index decreased at week 24 and was maintained or further improved at week 48, demonstrating sustained reductions in whole‑body inflammatory signal.
• Joint‑specific and enthesis‑specific indices showed improvement, indicating that apremilast addresses both articular and entheseal disease components.
• Exploratory regional scores suggested limited change at the heel and hip, with numerical improvement in knee inflammation, illustrating the granularity achievable with WB‑MRI‑based scoring.

These findings are consistent with earlier MOSAIC publications showing reductions in bone marrow oedema, synovitis and tenosynovitis in the hand and wrist, with no structural progression over 48 weeks, when apremilast was assessed using PsAMRIS and quantitative dynamic MRI approaches.

In participants with investigator‑defined PsA spondylitis and significant inflammatory back pain, apremilast also impacted axial inflammation:

• CANDEN total spine inflammation score and multiple sub scores (vertebral bodies, posterior elements, corner and non‑corner lesions, posterolateral elements) improved at weeks 24 and 48 compared with baseline.
• SPARCC spine and sacroiliac joint scores showed less pronounced change, underscoring that a detailed, anatomy‑rich system such as CANDEN may be more sensitive to distributed axial lesion patterns in PsA.

Together, these peripheral and axial results support apremilast’s ability to reduce MRI‑visible inflammation in early psoriatic arthritis and validate WB‑MRI, MRI‑WIPE and CANDEN as powerful tools to characterize treatment response in this setting.

The apremilast WB‑MRI study forms part of a broader MOSAIC imaging strategy, where advanced quantitative MRI has been integrated into a global phase 4 programme. Earlier work from the same programme used a continuous, computer‑assisted methodology implemented in IAG’s DYNAMIKA™ platform to quantify inflammatory activity in hand joints and tendons. That methodology captured reductions in synovitis and tenosynovitis under apremilast and demonstrated high sensitivity to early change.

In the current Annals of the Rheumatic Diseases paper, this philosophy is extended from regional to whole‑body and axial MRI, highlighting several key elements of IAG’s approach:

• Protocol design and endpoint selection: Embedding MRI‑WIPE, CANDEN and complementary regional scores into the trial design from the outset.
• Central imaging operations: Standardising acquisition, quality control and blinded central reading across multiple sites and time points.
• Quantitative analytics: Applying validated scoring systems and, where appropriate, computer‑assisted quantitative biomarkers to derive reproducible, regulator‑relevant imaging endpoints.

For clinical and R&D teams, this demonstrates that sophisticated MRI‑based endpoints can be operationalized at scale in complex, multi‑domain immunology studies without compromising feasibility.

This publication carries several important implications for sponsors designing psoriatic arthritis and broader immunology trials:

• Enhanced sensitivity to change
  Whole‑body and axial MRI can detect treatment‑induced changes that may not be fully captured by clinical scores alone, especially in early or heterogeneous PsA populations.
• Multi‑domain disease quantification
  Using MRI‑WIPE and CANDEN, investigators can quantify peripheral joints, entheses and spine inflammation within a unified framework, supporting domain‑specific analyses and mechanism‑of‑action insights.
• Regulatory and differentiation value
  Objective, centralised imaging biomarkers strengthen the evidence package around new therapies, supporting differentiation in crowded PsA and spondyloarthritis markets and informing discussions with regulators and HTA bodies.
• Platform for future studies
  The MOSAIC experience offers a template for designing imaging‑intensive phase 2–4 trials in PsA and other immune‑mediated inflammatory diseases, leveraging WB‑MRI, DCE‑MRI and advanced analytics as part of an integrated development strategy.

Image Analysis Group (IAG) partners with biotech and pharma companies to design and deliver imaging strategies that de‑risk immunology and rheumatology trials and maximize the value of imaging data. Our team offers:

• Scientific input into endpoint strategy and protocol design for PsA, axial disease and related IMID indications.
• Global central imaging operations, including protocol optimization, site qualification, training and standardized acquisition across MRI vendors.
• Central reading by expert musculoskeletal and spondyloarthritis radiologists, supported by robust adjudication processes.
• Advanced quantitative analytics using validated scoring systems and IAG’s proprietary DYNAMIKA™ platform to generate sensitive, reproducible imaging biomarkers.

Founded in 2007 and headquartered in London, Image Analysis Group (IAG) is a global specialist Imaging Clinical Research Organization (iCRO). IAG partners with leading pharmaceutical, biotechnology and medtech companies to design, execute and deliver imaging-based clinical trial endpoints across oncology, inflammatory disease, musculoskeletal, cardiometabolic and rare disease indications. Our proprietary DYNAMIKA™ platform integrates AI-driven image analysis, centralized quality control, regulatory-compliant reporting and real-time trial oversight. With teams across the UK, US, EU and India, IAG accelerates drug development timelines and strengthens the scientific integrity of imaging in regulatory submissions.

The publication of “Effect of apremilast on whole‑body magnetic resonance imaging of peripheral and axial inflammation in patients with psoriatic arthritis” in Annals of the Rheumatic Diseases provides further evidence that sophisticated MRI endpoints are feasible, informative and decision‑changing in complex PsA studies.

If you are planning a psoriatic arthritis, spondyloarthritis or broader immunology trial and would like to explore how whole‑body and axial MRI, along with advanced quantitative image analysis, could strengthen your program:

Get in touch with the Image Analysis Group (IAG) team via our contact form.

Or reach out directly to discuss your protocol, imaging strategy and timelines: contact@www.ia-grp.com.