Multinational Trial Examines Mepolizumab for Nasal Polyps

Introduction to Nasal Polyps

A recent multinational trial explored the effectiveness of mepolizumab in diminishing the necessity for surgery in patients suffering from recurring severe nasal polyps. Nasal polyps are benign growths that develop from the mucous membrane in the nasal passages, typically forming at the entrances of the sinus cavities. These polyps indicate inflammation of the nasal membrane, predominantly caused by a high concentration of inflammatory cells known as eosinophils. Larger polyps can lead to chronic nasal obstruction and congestion, significantly impacting a patient’s quality of life.

Treatment Options for Nasal Polyps

Existing treatment modalities for nasal polyps include the daily application of corticosteroid nasal sprays, long-term antibiotic therapy, and surgical intervention. Unfortunately, recurrent surgery is prevalent among patients.

Investigation of a Novel Treatment

A promising new treatment for nasal polyps involves an antibody targeting inflammatory cells, which is currently under investigation. Prior research has indicated that this antibody can effectively reduce the size of nasal polyps. To validate these findings, researchers at the Upper Airways Research Laboratory at Ghent University Hospital conducted a study with a larger participant pool. The primary aim was to determine the number of patients who no longer required surgery by the end of the treatment period. The findings were published in the Journal of Allergy and Clinical Immunology.

Study Design and Methodology

In this multicenter, double-blinded trial, patients from Belgium, the Netherlands, and the United Kingdom were randomly assigned to receive either a placebo (53 patients) or mepolizumab (54 patients). Participants were instructed to consistently use corticosteroid nasal sprays for three months leading up to the study. During the run-in period, which lasted 10 to 14 days before the study commenced, all patients used fluticasone nasal spray at a dosage of two sprays in each nostril every morning. This aspect could pose a limitation, as some patients might not respond positively to this specific corticosteroid, potentially exacerbating their symptoms compared to their regular nasal sprays. Participants then received either mepolizumab or a placebo intravenously every four weeks over six months, totaling six doses, while continuing the same intranasal corticosteroid throughout the study.

Results of the Trial

At the conclusion of the study period, a significantly greater number of patients in the mepolizumab group no longer met the criteria for surgical intervention. Notable improvements were recorded in the nasal polyp severity score among those receiving mepolizumab. Additionally, a marked enhancement in the total endoscopic nasal polyp score was observed in patients treated with mepolizumab compared to those on the placebo. Individual symptom scores, including mucus accumulation in the throat, nasal obstruction, and loss of smell, also showed significant improvement with mepolizumab. The most frequently reported side effects included headaches and nasopharyngitis; however, the incidence of these side effects was comparable in both treatment groups.

Conclusion and Future Research Directions

The results from this larger study corroborate previous findings regarding the efficacy of mepolizumab. This injectable treatment shows promise in reducing the need for surgical intervention in patients with severe nasal polyps, potentially enhancing their quality of life. Further studies with extended treatment durations, alternative dosing strategies, and thorough side effect analyses are necessary to validate these findings.

References

(1) Bachert C, Sousa AR, Lund VJ, et al. Reduced need for surgery in severe nasal polyposis with mepolizumab: Randomized trial. J Allergy Clin Immunol. 2017.
(2) Fried, MP. Nasal Polyps. Merck Manual Consumer Version. http://www.merckmanuals.com/en-ca/home/ear,-nose,-and-throat-disorders/nose-and-sinus-disorders/nasal-polyps