Eighty patients with bilateral common
warts of the extremities were treated at weekly intervals with
intralesional injections of either human
fibroblast interferon or placebo. Lyophilized
interferon (3 X 10(6) units) was diluted with 3 ml of normal sterile saline matched with identical vials of placebo. Eighty sets of three vials of human
fibroblast interferon or placebo were labeled either A or B by a controller who maintained the code until the experiment was completed. Each patient received 0.1 X 10(6) units of
interferon into the
warts on one side and placebo
injections into those on the matching extremity.
Warts were measured each week and the progress or lack thereof was scored on a scale of -1 (worse) to 3 (cured).
Therapy continued until either at least one extremity had cleared or the patient had received 10 weekly
injections. A final evaluation was scored by measuring the total progress of each patient during the study. Sixty-four patients were treated to completion. More than 81% of the
interferon-treated extremities were either cured or responded effectively to
therapy. Only 17% of the placebo-treated lesions responded in this fashion. A statistical analysis of these data confirms the effectiveness of intralesional
interferon therapy. The average number of
interferon injections until cure was 5.9 +/- 1.7. No adverse effects were observed. The applications of
interferon in patients with
epidermodysplasia verruciformis and flat
warts were also studied. Intralesional
interferon beta was, to a certain degree, effective for benign lesions of
epidermodysplasia verruciformis, but systemic treatments were not effective. Subcutaneous
interferon beta was, in an uncontrolled study, effective in 45% of patients with flat
warts.