The RhoA/Rho-kinase pathway plays a pivotal role in cold induced vasoconstriction, vascular smooth muscle cells function and vascular homeostasis. This study evaluates the efficacy of fasudil, a RhoA/Rho-kinase inhibitor, to reverse cold-induced vasospasm in patients with Raynaud’s phenomenon (RP) secondary to systemic sclerosis (SSc).

This is a single-center, double-blind, placebo-controlled, randomized, 3-period crossover study of oral fasudil (40 mg or 80 mg) or placebo administered 2 hours before a standardized cold challenge. The fall in skin temperature after the cold challenge and time to recover 50% and 70% of pre-challenge digital skin temperature were used as primary outcomes. Digital blood flow assessed by Laser Doppler, time to minimum skin temperature, and rate of skin cooling were also measured.

Seventeen patients with SSc and RP completed the study. After cold challenge, skin temperatures and the average time (minutes) to recover 50% (placebo: 7.9, fasudil 40 mg: 7.5, and fasudil 80 mg: 8.2; p=.791) and 70% (placebo: 18.2, fasudil 40 mg: 15.0, and fasudil 80 mg: 17.1; p=.654) of pre-challenge skin temperature were not significantly different across the three groups. The digital blood flow measurements were higher in fasudil treated groups than placebo but differences were not significant (p=.693).

Fasudil administered at single oral dose of 40 mg or 80 mg was not associated with significant benefit in term of skin temperature recovery time and digital blood flow after cold challenge.