Abatacept Approved for Adult PsA
On June 30, the U.S. Food and Drug Administration (FDA) approved abatacept (Orencia) to treat adults with active psoriatic arthritis (PsA).1 Abatacept is available as both an intravenous formulation and a subcutaneous injection.2 The approval was based on results of two randomized, double-blind, placebo-controlled trials, PsA-I and PsA-II, during which abatacept reduced or improved disease activity in both tumor necrosis factor inhibitor (TNFi)-naive and TNFi-exposed patients with high disease activity, and high tender and swollen joints counts.
During the studies, patients (N=594) had a disease duration of seven years or more. They also had active psoriatic arthritis, with three or more swollen or tender joints despite prior treatment with disease-modifying anti-rheumatic drug (DMARD) therapy, and had one qualifying psoriatic skin lesion of at least 2 cm in diameter. The primary endpoint of the studies was the proportion of patients who achieved ACR20 response at Week 24. In PsA-I and PsA-II, 37% and 61% of patients, respectively, had previously been treated with TNFi.
In PsA-I, which was a dosing study, patients (N=170) were randomized to receive placebo or abatacept intravenously at 3 mg/kg or 10 mg/kg based on weight, or two doses of 30 mg/kg followed by weight-based dosing of 10 mg/kg without escape for 24 weeks. Patients were dosed on Days 1, 15 and 29 and every 28 days thereafter. After Week 24, patients received open-label abatacept every 28 days. Stable doses of concomitant methotrexate, low-dose corticosteroids (equivalent to ≤10 mg of prednisone) and/or NSAIDs were also allowed. When enrolled, approximately 60% of these patients were receiving methotrexate. The ACR20 response for abatacept 10 mg/kg IV at Week 24 was 47.5% vs. placebo at 19% (P<0.05). Prior TNFi or non-biologic DMARD treatment did not dictate response.
In PsA-II, patients (N=424) were randomized (1:1) to receive weekly doses of placebo or 125 mg abatacept subcutaneously without a loading dose for 24 weeks. The treatment was followed by 125 mg subcutaneous abatacept given weekly in an open-label study design. Stable doses of concomitant methotrexate, sulfasalazine, leflunomide, hydroxychloroquine, low-dose corticosteroids and/or NSAIDs were allowed. At randomization, 60.4% of patients were receiving methotrexate. The ACR20 response for 125 mg subcutaneous abatacept at Week 24 was 39.4% vs. placebo at 22.3% (P<0.05). Prior TNFi or non-biologic DMARD treatment did not dictate response.
Both intravenous and subcutaneous abatacept-treated patients had improvements in enthesitis and dactylitis at Week 24. Also at Week 24, more intravenous abatacept-treated patients had a greater decrease from baseline in the Health Assessment Questionnaire-Disability Index (HAQ-DI) score compared with placebo-treated patients. Subcutaneous abatacept-treated patients had improvements in the HAQ-DI, but the change was not as pronounced.