Repository corticotropin injection reverses critical elements of the TLR9/B cell receptor activation response in human B cells in vitro

Acthar® Gel Treatment for Patients with Autoimmune and Inflammatory Diseases: An Historical Perspective and Characterization of Clinical Evidence

Acthar® Gel (repository corticotropin injection) is a naturally sourced complex mixture of adrenocorticotropic hormone analogs and other pituitary peptides that is believed to have both steroidogenic and nonsteroidogenic immunomodulatory effects via activation of melanocortin receptors in various cells throughout the body. Since 1952, Acthar has been approved by the US Food and Drug Administration to treat a variety of autoimmune and inflammatory diseases. Since 2014, Mallinckrodt Pharmaceuticals has conducted a large number of preclinical, clinical, and real-world-evidence studies of Acthar for the treatment of rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis and polymyositis, multiple sclerosis relapse, ophthalmic disorders, sarcoidosis, and nephrotic syndrome. To date, Acthar has been the subject of more than 500 publications, many of which demonstrate the safety and efficacy of Acthar in patients with inflammatory diseases for whom standard treatments were ineffective or intolerable. Here, we review the history of Acthar and the findings of studies that have investigated the mechanism of action, safety, efficacy, and real-world effectiveness of Acthar for the treatment of inflammatory diseases.

Results From a Phase 4, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study of Repository Corticotropin Injection for the Treatment of Pulmonary Sarcoidosis

INTRODUCTION

Long-term treatment of pulmonary sarcoidosis with glucocorticoids has been associated with toxicity and other adverse events, highlighting the need for alternative therapies. The goal of this study was to evaluate the efficacy and safety of repository corticotropin injection (RCI, Acthar^® Gel) in patients with pulmonary sarcoidosis and to validate endpoints for use in future clinical trials.

METHODS

In this multicenter, randomized, placebo-controlled trial, subjects received subcutaneous RCI (80 U) twice weekly or matching placebo through 24 weeks in a double-blind treatment phase, followed by an optional 24-week open-label extension. Efficacy was measured by glucocorticoid tapering, pulmonary function tests, chest imaging, patient-reported outcomes, and a novel sarcoidosis treatment score (STS). Safety was assessed by adverse events, physical examinations, vital signs, clinical laboratory abnormalities, and imaging. The study was terminated early due to low enrollment caused by the COVID-19 pandemic, thereby precluding statistical analysis.

RESULTS

Fifty-five subjects were randomized to receive either RCI (n = 27) or placebo (n = 28). Mean STS at week 24 showed greater improvement with RCI (1.4) compared with placebo (0.7). At week 48, those who remained on RCI had an STS of 1.8 compared with 0.9 in those who switched from placebo to RCI. More subjects in the RCI group discontinued glucocorticoids at week 24 compared to the placebo group. Glucocorticoid discontinuation was comparable at week 48 for those who switched from placebo to RCI and those who continued RCI. Similar trends in favor of RCI over placebo were observed with the other efficacy endpoints. No new or unexpected safety signals were identified.

CONCLUSIONS

RCI was safe and well tolerated, with trends in efficacy data suggesting greater improvement with RCI compared to placebo in patients receiving standard-of-care therapy for pulmonary sarcoidosis. The study also provided validation of efficacy endpoints that may be used in larger trials for pulmonary sarcoidosis.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03320070.

Pituitary neuropeptides and B lymphocyte function

This review discusses the accumulated evidence that pro-opiomelanocortin (POMC) gene products as well as other pituitary neuropeptides derived from related genes (Proenkephalin, PENK; Prodynorphin, PDYN, and Pronociceptin, PNOC) can exert direct effects on B lymphocytes to modulate their functions. We also review the available data on receptor systems that might be involved in the transmission of such hormonal signals to B cells.

Individual pituitary neuropeptides do not recapitulate the effects of repository corticotropin (Acthar®) on human B cells in vitro

Repository corticotropin injection (RCI), a complex mixture of adrenocorticotropic hormone (ACTH) analogs and other pituitary peptides, has been found to suppress key aspects of gene expression and cellular function in human B lymphocytes in vitro. The present studies reveal that neither individual POMC peptides (α-MSH, ACTH_1-39, ACTH_1-24, β-endorphin) nor other related pituitary neuropeptides are sufficient to elicit these effects, even though specific receptors capable of transmitting signals from these peptides are expressed by human B cells. RCI's direct effects on human B cells may require complementary signals from multiple components of the preparation.