Background: There is serological evidence for an association between Chlamydia pneumoniae and coronary heart disease. We investigated the hypothesis that an antichlamydial macrolide antibiotic, roxithromycin, can prevent or reduce recurrent major ischaemic events in patients with unstable angina.
Methods: The effect of roxithromycin was assessed in a double-blind, randomised, prospective, multicentre, parallel-group, placebo-controlled pilot study of 202 patients with unstable angina or non-Q-wave myocardial infarction. Patients were randomly assigned either roxithromycin 150 mg orally twice a day (n = 102) or placebo orally twice a day (n = 100). The treatment was for 30 days. Patients were followed up for 6 months. We report the primary clinical endpoints (cardiac ischaemic death, myocardial infarction, and severe recurrent ischaemia), assessed at day 31, in 202 patients on an intention-to-treat basis.
Findings: A statistically significant reduction in the primary composite triple endpoint rates was observed in the roxithromycin group: p = 0.032. The rate of severe recurrent ischaemia, myocardial infarction, and ischaemic death was 5.4%, 2.2%, and 2.2% in the placebo group and 1.1%, 0%, and 0%, in the roxithromycin group, respectively. No major drug-related adverse effects were observed.
Interpretation: Antichlamydial antibiotics may be useful in therapeutic intervention in addition to standard medication in patients with coronary-artery disease. Large-scale trials are needed to confirm these preliminary observations.