Rationale: Severe asthma is a major public health issue throughout the world. Increased bronchial smooth muscle (BSM) mass, a characteristic feature of airway remodeling in severe asthma, is associated with resistance to high-intensity treatment and poor prognosis. In vitro, the Ca²⁺-channel blocker gallopamil decreased the proliferation of BSM cells from patients with severe asthma.

Objectives: We conducted a double-blind, randomized, placebo-controlled study to evaluate the effect of gallopamil on airway remodeling in patients with severe asthma.

Methods: Subjects received either gallopamil (n = 16) or placebo (n = 15) for 1 year and were monitored for an additional 3-month period. Airway remodeling was analyzed at baseline and after treatment phase using both fiberoptic bronchoscopy and computed tomography scan. The primary end point was the BSM area. Secondary end points included normalized BSM thickness and frequency of asthma exacerbations.

Measurements and Main Results: BSM area was reduced in the gallopamil group (baseline vs. end of treatment) but was unchanged in the placebo group. Between-group differences in BSM area were not significantly different in gallopamil versus placebo groups. By contrast, between-group differences in normalized BSM thickness were significantly different between the two groups. The mean number of exacerbations per month was not different during the treatment phase in gallopamil versus placebo group but was significantly lower in patients previously treated with gallopamil during the follow-up period. There were no differences between the groups with respect to overall side effects.

Conclusions: Gallopamil treatment for 12 months reduces BSM remodeling and prevents the occurrence of asthma exacerbations.

Clinical trial registered with www.clinicaltrials.gov (NCT 00896428).