Objective: The macrolide family of antibiotics (erythromycin, clarithromycin, and others), have both antimicrobial and immunomodulatory effects. This study explored the effect of clarithromycin on the clinical course of patients with undifferentiated connective tissue disease (UCTD) in a 12-week open-label study.
Methods: The diagnosis of UCTD was based on symptoms/signs of connective tissue disease, and the presence of 1 or more positive autoimmune disease tests, but with insufficient criteria to make a definitive diagnosis. Screening and monthly follow-up visits over 12 weeks included the following: history and physical examination; concurrent medications; the 68/66 tender/swollen joint count; visual analog scores 0 to 100 mm for patient and physician global assessment of disease activity, and patient pain; antinuclear antibody panel, rheumatoid factor, erythrocyte sedimentation rate, C-reactive protein, and blood chemistry.
Results: Seven patients with rheumatic disease were treated with clarithromycin; 6 of 7 had symptomatic relief. Two subjects treated empirically before the decision to perform an open-label study responded favorably. Four of 5 patients who completed the prospective open-label study had mean maximal improvements from baseline of 78, 75, and 79% in patient pain, patient global, and investigator global assessments, respectively. Pain relief occurred as early as 1 week. Drug withdrawal with rechallenge in 2 patients resulted in flare followed by recapture of symptomatic relief.
Conclusions: Clarithromycin, a macrolide antibiotic, led to clinical improvement in patients with UCTD. Efficacy and safety data support further investigation of macrolide antibiotic use as a primary or adjunctive treatment in various connective tissue diseases.