Abstract
BACKGROUND
Relaxin is a pregnancy-related hormone that has tissue remodeling and antifibrotic effects. Systemic sclerosis (scleroderma) is characterized by fibrosis of the skin, vasculature, and internal organs.
OBJECTIVE
To assess the efficacy, safety, and dose-response effect of recombinant human relaxin in patients with scleroderma.
DESIGN
Multicenter, parallel-group, randomized, double-blind, placebo-controlled trial.
SETTING
Academic referral centers.
PATIENTS
68 patients who had had stable, diffuse scleroderma (moderate to severe) for less than 5 years.
INTERVENTION
Recombinant human relaxin, 25 or 100 microg/kg of body weight per day, or placebo administered by continuous subcutaneous infusion over 24 weeks.
MEASUREMENTS
Modified Rodnan skin score was the primary efficacy measure. Secondary measurements were pulmonary function, the Health Assessment Questionnaire, and other measures of scleroderma that reflected fibrosis.
RESULTS
Patients who received 25 microg/kg of recombinant human relaxin per day had significantly lower skin scores than those who received placebo (mean change, -3.6 at 4 weeks [P = 0.021], -7.5 at 12 weeks [P < 0.001], and -8.7 at 24 weeks [P = 0.040]). Similar trends were noted in other outcome measures, including forced vital capacity, measures of oral aperture and hand extension, functional status, and global assessment. Patients who received 100 microg/kg of relaxin per day did not differ from those who received placebo. Drug-related adverse events included menometrorrhagia, reversible anemia, and complications of the subcutaneous drug administration system (site irritation and local infection).
CONCLUSIONS
Twenty-four weeks of recombinant human relaxin, 25 microg/kg per day, is associated with reduced skin thickening, improved mobility, and improved function in patients with moderate to severe diffuse scleroderma.
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