Background/Purpose: Rheumatoid arthritis (RA) is an autoimmune disorder associated with chronic inflammation and commonly treated with disease-modifying anti-rheumatic drugs (DMARDs) and corticosteroids. Repository corticotropin injection (RCI) is approved in the United States as adjunctive therapy for short‑term administration (during an acute episode or exacerbation) in RA (selected cases may require low-dose maintenance therapy). Here, we present interim data from the initial 12-week open-label phase of an ongoing phase 4, multicenter, 2‑part study evaluating the efficacy, safety, and appropriate duration of RCI therapy in patients with persistently active RA despite receiving 1 or 2 conventional synthetic or biologic DMARDs (cs/bDMARDs) and corticosteroids.

Methods: In the open‑label period (Part 1, Weeks 0–12), all enrolled patients received RCI 1 mL (80 U) subcutaneously (SC) twice per week for 12 weeks. After the initial 12 weeks, patients who achieved low disease activity (LDA; DAS28-ESR score <3.2) at Week 12 continued in the double‑blind maintenance phase of the trial (Part 2), during which they were randomized 1:1 to receive either RCI 1 mL (80 U) SC or matching placebo 1 mL SC twice per week for an additional 12 weeks. The primary endpoint was the proportion of patients who achieved LDA at Week 12. Secondary endpoints included assessment of the safety and tolerability of RCI. Disease activity was also assessed by the proportion of patients who achieved 20%, 50%, and 70% improvement in American College of Rheumatology (ACR) response criteria (ACR20, ACR50, and ACR70, respectively) at Week 12.

Results: As of 10 May, 2018, 116 patients had enrolled, 100 had completed, 2 were ongoing, and 14 had discontinued the 12-week open-label period of the study. Among patients who completed the open-label period, 84% were female, and the mean age of patients was 54 years. Twelve weeks of RCI treatment resulted in >60% of patients achieving LDA; patient baseline characteristics and the results of the primary and select secondary endpoints for this interim analysis are presented in Table 1. Forty six adverse events (AEs) were reported among the 116 patients enrolled in the study, and 2 patients reported serious AEs (chest pain and pneumonia). The most common AEs were headache (n=10), urinary tract infection (n=4), hyperglycemia (n=3), and pharyngitis (n=3).

*Sub-components of the 28-joint count, a measure used to determine the DAS28-ESR score and ACR criteria scale.

Conclusion: In this ongoing study, RCI was a potentially safe and effective treatment option in patients with persistently active RA who were nonresponsive to corticosteroids and cs/bDMARD treatment, as demonstrated by improvement in multiple measures of disease activity during a 12-week open-label period.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/a-multicenter-study-assessing-the-efficacy-and-safety-of-repository-corticotropin-injection-in-patients-with-rheumatoid-arthritis-preliminary-interim-data-from-the-open-label-treatment-period/