Repository corticotropin injection in patients with rheumatoid arthritis resistant to biologic therapies

Although synthetic and biologic disease-modifying antirheumatic drugs are available, many patients with rheumatoid arthritis have a difficult-to-control disease and need other treatment options. Repository corticotropin injection (RCI) may alleviate symptoms and exacerbations in patients with refractory disease.

Nine patients with refractory rheumatoid arthritis were included in this study. Patients were maintained on their baseline therapies with a minimum of 7.5 mg prednisone daily. RCI was given daily at 40 U for 7 days. Patients who had an adequate disease response were given 40 U twice weekly through Week 12. For patients who had inadequate disease response, the dose was increased to 80 U daily for 7 days, followed by 80 U twice weekly through Week 12.

The primary endpoint was >1.2 point reduction in the Disease Activity Score 28 using C-reactive protein (DAS28-CRP) at Week 12. Secondary endpoints were improvements in Health Assessment Questionnaire-Disease Index and Functional Assessment of Chronic Illness Therapy scores. Six of the nine patients met the primary endpoint. The average change in DAS28-CRP from baseline to Week 12 was numerically greater with 40 U than with 80 U RCI. Functional Assessment of Chronic Illness Therapy and Health Assessment Questionnaire-Disease Index improved as early as Week 1, and the improvements remained throughout treatment.

There was no association between cortisol levels and low-dose RCI response. No serious adverse events occurred. RCI produced a clinically meaningful reduction in markers of disease activity, improved health-related quality of life, and a favorable safety profile. The response rate to RCI was substantial and shows promise in this difficult-to-treat population.