Among patients with moderate to severe asthma, dupilumab reduced exacerbations by almost 50%, while also allowing glucocorticoid-treated patients to cut their use of that medication by 70%, with no increased risk of exacerbation.
The pair of placebo-controlled studies –and – also showed treatment-associated stability in forced expiratory volume (FEV1) evidence of lung remodeling among those who took the antibody, , of Washington University, St. Louis, and his colleagues reported in the .
By week 12, FEV1 it had already increased by 0.32 L, they said.
“An analysis of the postbronchodilator FEV1 slope showed a loss of lung function in patients who received placebo and no loss in those who received dupilumab, findings that suggest a potential effect of dupilumab on airway remodeling,” wrote Dr. Castro and his colleagues. “The slope analysis showed that patients who received placebo lost, on average, approximately 40 mL annually, which is consistent with data from other cohorts of patients with asthma.”
Dupilumab is an anti–interleukin-4 alpha antibody that blocks both IL-4 and IL-13. The Quest trial examined efficacy and safety of two doses (200 mg and 300 mg every 2 weeks), compared with placebo in patients with uncontrolled asthma. Venture examined efficacy and safety of 300 mg or placebo as add-on therapy for patients with severe asthma who were taking glucocorticoids.
Liberty Asthma Quest
This 52-week study randomized 1,902 patients with severe, uncontrolled asthma to placebo or dupilumab 200 mg or 300 mg every other week. The primary endpoints were annual rate of severe asthma exacerbations and the change in FEV1 by week 12. The study also looked at these endpoints in patients whose baseline eosinophil count was greater than 300 per cubic millimeter.
Patients were a mean of 48 years old with a mean baseline FEV1 of about 1.75 L (about 58% of the predicted normal value). They had a mean of two exacerbations per year and an average eosinophil count of about 350 per cubic millimeter.
Both doses outperformed placebo in all endpoints.
Among those taking 200 mg, the annual relapse rate was 0.46 versus 0.87 among those taking placebo – a significant 47.7% risk reduction. Among those taking 300 mg, the exacerbation rate was 0.52 versus 0.97; this translated to a significant 46% risk reduction.
The response rate was even greater among those with an eosinophil count greater than 300 per cubic millimeter: 0.37 for 200 mg and 0.40 for 300 mg versus the placebo rates of 1.08 and 1.24. This translated to risk reductions of 65.8% and 67.4%, respectively.
By week 12, FEV1 had significantly increased by 0.32 L in the 200-mg group and by 0.34 L in the 300-mg group, compared with nonsignificant increases among those taking placebo.
Again, patients with the high eosinophil counts experienced the greatest benefits, with FEV1 increasing by a mean of 0.43 L at 12 weeks in the 200-mg group and by 0.47 L in the 300-mg group, significantly better than either placebo comparator.
The benefit was already noticeable by the 2-week evaluation, the investigators noted.
Dupilumab appeared safe; injection-site reactions were the most common adverse event, occurring in 15% of the low-dose group and 18% of the high-dose group. However, 52 patients taking the drug experienced eosinophilia, compared with four of those taking placebo (4.1% vs. 0.6%).
Four of those taking the study drug experienced clinical symptoms associated with eosinophilia, including worsening eosinophilia and chronic eosinophilic pneumonia.