Promising Results for Repository Corticotropin Injections in Persistent RA
This month, promising results from a study on the effect of repository corticotropin injections as an add-on therapy for RA that has not responded to DMARDs (disease-modifying antirheumatic drugs) or corticosteroids were presented at the European Congress on Rheumatology’s annual EULAR meeting (European League Against Rheumatism). Repository corticotropin injections contain a compound similar to our body’s natural ACTH (adrenocorticotropic hormone), which may have immunomodulatory and anti-inflammatory effects. It is currently sold under the name H.P. Acthar Gel and is manufactured by Mallinckrodt Pharmaceuticals. These injections are currently FDA approved for the treatment of infantile spasms, multiple sclerosis exacerbations, and other allergic, dermatologic, and rheumatologic disorders.
Repository corticotropin injections for RA
Recruitment of study participants
The first portion of the study was open-label and involved 259 individuals with persistent RA. Overall, 235 completed the first 12-week portion of the study in which they all received subcutaneous (under the skin) repository corticotropin injections twice a week. The researchers used a scale called the Disease Activity Score-28 for Rheumatoid Arthritis with ESR (DAS28-ESR) to monitor participants’ responses to treatment, and found that over 60% were able to achieve low disease activity (LDA) with the injections.
Who was eligible for the study?
Individuals with a DAS28-ESR score of higher than 3.2 and who had previously not responded to DMARDs or corticosteroids were eligible for the study. The repository corticotropin injections were given in addition to a stable dose of corticosteroid and methotrexate or a biologic throughout the study.
Results of the first phase
Improvement in RA symptoms based on ACR criteria
More specifically, over 80% achieved a 20% improvement in their RA as defined by the ACR20 (American College of Rheumatology criteria). This criteria takes into account the amount of inflammation present in the body, how much pain an individual is in, their functionality, and how the individual with RA and their doctor feel they are doing overall. Further, over 60% achieved an ACR50 and 30% achieved an ACR70, with 50% and 70% improvements, respectively.
The 12-week follow-up phase
Repository corticotropin injections vs a placebo
The over 60% who responded well to the injections were allowed to continue on in the trial for another 12-week phase in which they were randomly assigned to keep getting the repository corticotropin injections or receive a placebo (non-active injection). Over 150 individuals who initially responded to the repository corticotropin injections completed this follow-up phase, and half were allowed to continue on with the treatment, while the other half got a placebo. The participants and researchers were not aware of who was in which group, to prevent bias.
Results after followup: maintained low disease activity
After the end of the second 12 weeks, 62% and 43% of participants on the repository corticotropin injections and the placebo (respectively) were able to maintain their LDA status. This was a statistically significant result that showed that repository corticotropin injections may be a helpful add-on therapy when other treatment options aren’t providing necessary relief.
Extended benefits three months later
Additionally, the results point toward the long-term benefits of these injections, since nearly half of those who stopped at the 12-week point were still experiencing some of the benefits three months later. Further research is needed, however, these results make repository corticotropin injections seem promising as a future add-on treatment option.
Reported side effects
The repository corticotropin injections were found to have no significant impact on bone formation and breakdown. Over a third of participants reported side effects, with the most common being urinary tract infection, headache, and a sore throat. Serious side effects like pneumonia, craniocerebral injury, and non-cardiac chest pain were reported by 1.2% of participants. The majority of study participants were women around 50 years of age.