IMPACT 2 Clinical Study Overview

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The approval for REMICADE in psoriatic arthritis was based on the results of the IMPACT 2 study. IMPACT stands for Induction and Maintenance Psoriatic Arthritis Clinical Trial.

Who were the study participants?

The study included 200 adult patients at 36 research centers in North America and Europe. All patients had active psoriatic arthritis for at least 6 months and an inadequate response to disease modifying drugs (e.g., methotrexate) or nonsteroidal anti-inflammatory drugs (e.g., ibuprofen). Study participants also had at least 1 skin (plaque psoriasis) lesion > 2 cm in diameter.

Which medications were given to study participants?

Study participants were divided into 2 groups (100 patients in each group) and received either 5 mg/kg REMICADE or placebo intravenous infusions at Weeks 0, 2, 6, 14, and 22. Forty-six percent of patients continued on stable doses of methotrexate (< 25 mg/week).

Summary of Results

Signs and symptoms were measured by the American College of Rheumatology (ACR) score. The score includes the number of tender and swollen joints; the patient's and doctor's assessment of how well the patient is doing; the amount of pain present; ability to perform physical activities; and results of blood tests that monitor inflammation (e.g., CRP). Higher ACR scores represent worse signs and symptoms of arthritis, like joint pain and tenderness.

At the beginning of the study, all patients were examined by a doctor and given an ACR score. At Week 14 and 24 of the study, patients were examined again. Patients who had a 20% decrease in the original ACR score were classified as having an ACR 20 score. In other words, a patient's signs and symptoms improved by 20%. Some patients had ACR 50, and ACR 70 scores, which represent 50% and 70% reductions, respectively.

More patients treated with REMICADE had ACR 20, ACR 50, and ACR 70 scores after 24 weeks. In other words, these patients had less pain, joint swelling, and tenderness after 6 months of treatment with REMICADE. The response was similar regardless of whether or not patients received methotrexate.

Safety information from the IMPACT 2 study

During the IMPACT 2 study, the incidence of side effects was similar for patients treated with REMICADE and placebo. The most frequently reported side effect was upper respiratory tract infection. The incidence of serious side effects was low and was similar in patients treated with REMICADE and placebo. The safety information from IMPACT 2 needs to be reviewed with the other safety information from other clinical studies and experience.

Please read the important safety information below, and discuss it with your doctor.