PALACE 2: Efficacy and Safety Study of Apremilast to Treat Active Psoriatic Arthritis

Psoriatic arthritis (PsA) is an inflammatory arthritis that occurs in 6-39% of psoriasis
patients. The immunopathogenesis of PsA, which mirrors but is not identical to that seen in
psoriatic plaques, reflects a complex interaction among resident dendritic, fibroblastic and
endothelial cells, and inflammatory cells attracted to the synovium by cytokines and
chemokines. Apremilast (CC-10004) is a novel oral agent that modulates multiple inflammatory
pathways through targeted phosphodiesterase type 4 (PDE4) enzyme inhibition. Therefore,
apremilast has the potential to be effective in the treatment of PsA.

Inclusion Criteria:

- Males or females, aged ≥ 18 years at time of consent.

- Have a diagnosis of Psoriatic Arthritis (PsA, by any criteria) of ≥ 6 months duration.

- Meet the Classification Criteria for Psoriatic Arthritis (CASPAR) PsA at time of
screening.

- Must have been inadequately treated by disease-modifying antirheumatic drugs (DMARDs)

- May not have axial involvement alone

- Concurrent Treatment allowed with methotrexate, leflunomide, or sulfasalazine

- Have ≥ 3 swollen AND ≥ 3 tender joints.

- Males & Females must use contraception

- Stable dose of nonsteroidal anti-inflammatory drugs (NSAIDs), narcotics and low dose
oral corticosteroids allowed.

Exclusion Criteria:

- Pregnant or breast feeding.

- History of allergy to any component of the investigational product.

- Hepatitis B surface antigen and/or Hepatitis C antibody positive at screening.

- Therapeutic failure on > 3 agents for PsA or > 1 biologic tumor necrosis factor (TNF)
blocker