SAN DIEGO, CA—Ixekizumab is well-tolerated and maintains or exceeds clinical improvements in patients with rheumatoid arthritis who participated in the open-label extension study through Week, according to results presented at the 2013 ACR/ARHP Annual Meeting.

Marc C. Genovese, MD, of Stanford University, Palo Alto, CA, and colleagues conducted a randomized, double-blind, Phase 2 study of patients with moderate-to-severe rheumatoid arthritis who were naïve to biologic therapy (bDMARD-naïve) or were inadequate responders to TNF inhibitors (TNF-IR). Long-term safety and efficacy of ixekizumab were evaluated in an optional open-label extension.

Subcutaneous placebo or ixekizumab was administered to 260 bDMARD-naïve patients (ixekizumab 3, 10, 30, 80, or 180 mg) and 188 TNF-IR patients at Weeks 0, 1, 2, 4, 6, 8, and 10 receiving concomitant conventional DMARD therapy (Part A). After treatment was paused between Weeks 10—16, 232 bDMARD-naïve and 158 TNF-IR patients elected to participate in the open-label extension of the study. Ixekizumab 160mg was administered subcutaneously to these individuals at Weeks 16, 18, and 20 and then every 4 weeks through Week 64 (Part B).

A total of 202 bDMARD-naïve (87%) and 99 TNF-IR (62%) patients completed the open-label extension period. At Week 16, ACR20 response rates were maintained or improved after switching to 160mg every 4 weeks through Week 64. Similar maintenance or improvement was seen for ACR50 and ACR70 responses and for DAS28-CRP in both populations.

Response was maintained in 89%, 77%, and 69% of bDMARD-naïve patients with an ACR20 (n=107), ACR50 (n=39), or ACR70 (n=13) response at Week 16, respectively. In TNF-IR patients with ACR20 (n=41), ACR50 (n=18), or ACR70 (n=11) response at Week 16, the response was maintained in 76%, 67%, and 44% of patients, respectively. Similar maintenance of response was observed for EULAR responses.

For patients who received placebo in Part A of the study, disease activity decreased in Part B to levels comparable to patients assigned to ixekizumab groups in Part A. DAS28<2.6 was reached in 23% of bDMARD-naïve (n=46) and 22% of TNF-IR patients (n=23) after 64 weeks of treatment with ixekizumab.

During Part B of the study, adverse events occurred in 73% (n=283) of patients but were mild to moderate in severity and none lead to study discontinuation. Serious adverse events occurred in 9% (n=35) patients; of these, 2% (n=9) were serious infections. No mycobacterial or systemic fungal infections were reported.