BACKGROUND: Chronic viral infections of the heart are considered one antecedent event leading to progressive dysfunction of the myocardium, often with an impaired prognosis due to a virus- or immune-mediated myocardial injury. Symptomatic treatment does not influence the viral cause of heart failure, and the effect of antiviral treatment has not been determined, yet. METHODS AND RESULTS: In this phase II study 143 patients with symptoms of heart failure and biopsy-based confirmation of the enterovirus (EV), adenovirus, and/or parvovirus B19 genomes in their myocardial tissue were randomly assigned to double-blind treatment, and received either placebo (n = 48) or 4 x 106 (n = 49) and 8 x 106 IU (n = 46) interferon beta-1b (IFN-beta-1b) for 24 weeks, in addition to standard heart failure treatment. Patients with active myocarditis or other specific causes of heart failure were excluded. Compared to placebo, virus elimination and/or virus load reduction was higher in the IFN-beta-1b groups (odds ratio 2.33, p = 0.048), similarly in both interferon groups and both strata. IFN-beta-1b treatment was associated with favourable effects on NYHA functional class (p = 0.013 at follow-up week 12), improvement in quality of life (Minnesota Heart Failure score; p = 0.032 at follow-up week 24) and patient global assessment (follow-up week 12 to follow-up week 24; p = 0.039). The frequency of adverse cardiac events was not higher in the IFN-beta-1b groups compared to the placebo group. CONCLUSIONS: Immunomodulatory IFN-beta-1b treatment is a well-tolerated and safe treatment option, leading to effective virus clearance or reduction of the virus load in patients with chronic viral cardiomyopathy. Favourable clinical effects assess quality of life, NYHA functional class, and patient global assessment.
