Arcalyst (Rilonacept)

Arcalyst (rilonacept) is an anti-inflammatory therapy approved by the U.S. Food and Drug Administration (FDA) to treat adults and children 12 and older who live with cryopyrin-associated periodic syndromes, or CAPS. These syndromes include familial cold autoinflammatory syndrome (FCAS) and muscle-wells syndrome (MWS).

Arcalyst, distributed by Regeneron Pharmaceuticals, also is being investigated for the treatment of systemic scleroderma.

How Arcalyst works

Scleroderma is an autoimmune disease caused by an overactive immune system that mistakenly attacks healthy tissues, leading to scarring and thickening of the connective tissue in multiple tissues and organs.

Rilonacept, the active substance in Arcalyst, is an interleukin (IL) inhibitor. It works by attaching to interleukin-1 beta (IL-1β), an immune system protein that causes inflammation, and blocking its activity, which helps reduce inflammation and relieve the symptoms of scleroderma.

Arcalyst in clinical trials for systemic scleroderma

The effectiveness of Arcalyst in the treatment of systemic scleroderma was studied in a Phase 1/2 randomized, double-blind, placebo-controlled study (NCT01538719) called IL1-TRAP.

In the study, designed to provide preliminary data for a larger study, researchers used a four-gene biomarker of skin disease as the primary goal, in which a high biomarker score was equivalent to a high skin score and suggested higher disease severity.

Secondary outcomes included other measures of disease activity, including the modified Rodnan skin score (a measure of skin thickness), and health assessment questionnaire disability index (HAQ-DI), a questionnaire in which patients report the amount of difficulty experienced when performing certain activities.

The trial was completed in August 2017, but no results have been published yet.


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