Efalizumab for the treatment of psoriatic arthritis

Psoriatic arthritis (PsA) is an inflammatory arthritis associated with psoriasis. Efalizumab, a T cell-targeted, recombinant human monoclonal antibody, is approved for the treatment of adult patients with chronic moderate to severe plaque psoriasis. The effect of efalizumab therapy on PsA has not previously been investigated.

This phase II randomized, double-blind, placebo-controlled multicenter study evaluated the efficacy and safety of efalizumab for the treatment of PsA.

Patients were required to be on at least one of the following concomitant systemic therapies for PsA: nonsteroidal anti-inflammatory drugs, corticosteroids, and/or sulfasalazine or methotrexate. One hundred fifteen patients with active PsA were enrolled and randomized in the study. Of these, 107 were treated weekly with efalizumab 1 mg/kg or placebo for 12 weeks, followed by 12 additional weeks of open-label efalizumab.

At week 12, 28% of efalizumab-treated patients achieved ACR-20 response (a 20% reduction from the baseline in the American College of Rheumatology response criteria), the primary end point, compared with 19% of placebo patients (p = .27). The safety profile was comparable between efalizumab- and placebo-treated patient groups, regardless of methotrexate background therapy, and no worsening of joint disease occurred with efalizumab therapy.

Efalizumab was not effective in treating PsA; efalizumab therapy did not worsen PsA. The efalizumab safety profile does not appear to be altered with the concomitant use of methotrexate therapy.