Background
Patients with eosinophilic nasal polyposis frequently require surgery, and recurrence rates are high.

Objective
We sought to assess the efficacy and safety of mepolizumab versus placebo for severe bilateral nasal polyposis.

Methods
This randomized, double-blind, placebo-controlled trial recruited patients aged 18 to 70 years with recurrent nasal polyposis requiring surgery. Patients received 750 mg of intravenous mepolizumab or placebo every 4 weeks for a total of 6 doses in addition to daily topical corticosteroid treatment. The primary end point was the number of patients no longer requiring surgery at Week 25 based on a composite end point of endoscopic nasal polyp score and nasal polyposis severity visual analog scale (VAS) score. Secondary end points included change in nasal polyposis severity VAS score, endoscopic nasal polyp score, improvement in individual VAS symptoms (rhinorrhea, mucus in throat, nasal blockage, and sense of smell), patient-reported outcomes, and safety.

Results
One hundred five patients received mepolizumab (n = 54) or placebo (n = 51). A significantly greater proportion of patients in the mepolizumab group compared with the placebo group no longer required surgery at Week 25 (16 [30%] vs 5 [10%], respectively; P = .006). There was a significant improvement in nasal polyposis severity VAS score, endoscopic nasal polyp score, all individual VAS symptom scores, and Sino-Nasal Outcome Test patient-reported outcome score in the mepolizumab compared with placebo groups. Mepolizumab's safety profile was comparable with that of placebo.

Conclusion
In patients with recurrent nasal polyposis receiving topical corticosteroids who required surgery, mepolizumab treatment led to a greater reduction in the need for surgery and a greater improvement in symptoms than placebo.