Amgen has presented detailed findings from a head-to-head phase III study comparing the safety, efficacy and immunogenicity of biosimilar candidate ABP 501 with adalimumab in patients with moderate-to-severe rheumatoid arthritis.

The study met the primary endpoint, which was achievement of ACR20 (20% or greater improvement in ACR assessment) at week 24. At week 24, 74.6% of patients in the ABP 501 group and 72.4% in the adalimumab group met the ACR20 response criteria. The risk ratio of ACR20 was 1.039 with the two-sided 90% = CI of 0.954-1.133, which fell within the predefined equivalence margin.

"Demonstrating biosimilarity is scientifically complex, but Amgen's 35 years of proven biologic R&D experience is facilitating the advancement of exciting programs like ABP 501," said Sean E. Harper, M.D., executive vice president of R&D at Amgen. "Our long-term commitment to advancing care in inflammation is as strong as ever, with a portfolio of novel and biosimilar compounds that have the potential to benefit patients worldwide."

ABP 501 is being developed as a biosimilar candidate to adalimumab, an anti-TNF-a monoclonal antibody, which is approved in many countries for the treatment of inflammatory diseases, including moderate-to-severe rheumatoid arthritis, moderate-to-severe plaque psoriasis, moderate-to-severe polyarticular juvenile idiopathic arthritis, psoriatic arthritis, ankylosing spondylitis, moderate-to-severe Crohn’s disease and moderate-to-severe ulcerative colitis.

Secondary endpoints included the achievement of ACR50 and ACR70 (a 50 or 70% improvement in ACR assessment) within the predefined equivalence margin. At week 24, patients treated with ABP 501 compared with those treated with adalimumab achieved ACR50 (49.2% percent v. 52%) and ACR70 (26% vs. 22.9%), respectively. Additionally, the secondary endpoint of a difference in change from baseline of DAS28-CRP (Disease Activity Score examines 28 joints in the body as measured by C reactive protein in the blood) over the entire study was also achieved. The difference in mean change from baseline in DAS28-CRP between ABP 501 and adalimumab was -0.01 (90% CI, -0.18 to 0.17) at week 24.