Add-On Mepolizumab Promising Option for Chronic Rhinosinusitis with Nasal Polyps

Joseph Han, MD

A new study found that mepolizumab was safe and efficacious in treating nasal polyps and nasal obstruction in patients affected by chronic rhinosinusitis. 

These findings were corroborated by the SYNAPSE study, a randomized, double-blind, placebo-controlled, parallel-group, phase 3 trial led by Joseph Han, MD, Department of Otolaryngology, Eastern Virginia Medical School.

The study included 93 centers across 11 countries and enrolled patients ≥18 years of age with recurrent, refractory, severe, bilateral nasal polyp symptoms.

“Chronic rhinosinusitis with nasal polyps affects approximately 2–4% of the general population, and long-term use of systemic corticosteroids is associated with adverse effects,” the investigators wrote. As such, they evaluated the monoclonal antibody mepolizumab as a potential adjunctive therapy for this patient population.

The Study

Han and colleagues randomly assigned 407 patients 1:1 to subcutaneously receive either mepolizumab 100 mg or placebo every 4 weeks.

In addition to mepolizumab or placebo treatment, patients also received standard of care, which included mometasone furoate intranasal spray for ≥8 weeks prior to and during study period, saline nasal irrigations, systemic corticosteroids or antibiotics (or both). Standard of care was administered for 52 weeks.

All patients had a nasal obstruction symptom visual analogue scale (VAS) score of >5. The investigators also noted that patients were eligible for repeat nasal surgery (overall symptoms VAS score >7; endoscopic nasal polyps score of ≥5; minimum score of 2 for each nasal cavity) despite standard of care and had at least one nasal surgery in the past decade.

“The coprimary endpoints were change from baseline in total endoscopic nasal polyp score at week 52 and in mean nasal obstruction VAS score during weeks 49–52, assessed in the intention-to-treat population (ITT),” the investigators wrote.

The Results

Thus, they reported that the total endoscopic nasal polyp score significantly improved at week 52 from baseline in the mepolizumab group—when compared with placebo (adjusted difference in medians, −0.73; 95% CI, −1.11 to −0·34; P<0.0001).

Furthermore, the team observed significant improvements in nasal obstruction VAS score during weeks 49-52 (-3.42; 95% CI, -4.09 to -2.18; P<.0001).

In terms of adverse events, 15% of mepolizumab patients reported effects related to study treatment—versus 9% of placebo patients.

Additionally, serious adverse events occurred in 6% of patients receiving mepolizumab, with such events occurring in 6% of patients receiving placebo. However, none were considered related to mepolizumab treatment.

“Mepolizumab treatment improved nasal polyp size and nasal obstruction compared with placebo, with no new safety indications, in patients with recurrent, refractory severe chronic rhinosinusitis with nasal polyps,” Han and colleagues wrote. “These findings suggest that mepolizumab provides an effective add-on treatment option to standard of care in this population.”

The study, “Mepolizumab for chronic rhinosinusitis with nasal polyps (SYNAPSE): a randomised, double-blind, placebo-controlled, phase 3 trial,” was published online in JAMA Respiratory Medicine.