A comparative study of PF‐06438179/GP1111 (an infliximab biosimilar) and reference infliximab in patients with moderate to severe active rheumatoid arthritis: A subgroup analysis

AIM: PF‐06438179/GP1111 (PF‐SZ‐IFX) is a biosimilar of reference infliximab (Remicade(®)). This analysis compared the efficacy of PF‐SZ‐IFX and reference infliximab sourced from the European Union (IFX‐EU) in patient subgroups from a randomized, comparative study of PF‐SZ‐IFX versus IFX‐EU. METHODS: Patients with rheumatoid arthritis were randomized 1:1 to PF‐SZ‐IFX (n = 324) or IFX‐EU (n = 326); study drug (3 mg/kg) was administered intravenously at weeks 0, 2, and 6, then every 8 weeks thereafter. Subgroup analyses of efficacy endpoints such as American College of Rheumatology criteria for ≥20% clinical improvement (ACR20), change in high‐sensitivity C‐reactive protein (hs‐CRP), and change in Disease Activity Score in 28 joints, four components based on hs‐CRP (DAS28‐CRP) at weeks 14 and 30 were performed by age, gender, race, region, immunogenicity status, and treatment history. RESULTS: Overall, ACR20 response rates as well as changes in DAS28‐CRP and hs‐CRP at week 14 were similar between PF‐SZ‐IFX and IFX‐EU within the subgroups of age, gender, race, region, treatment history, and immunogenicity status. Results to week 30 support overall similarity in efficacy between the two treatment arms in all subgroups. CONCLUSION: Overall, PF‐SZ‐IFX and IFX‐EU were similar in efficacy within the analyzed subgroups of age, gender, race, region, treatment history, and immunogenicity status. The efficacy results from these subgroup analyses were aligned with the previously described results for the overall population up to week 30.