The Effect of Intra-sinus Application of Betamethasone Dipropionate Nasal Cream on Patients with Chronic Rhinosinusitis Post Functional Endoscopic Sinus Surgery (FESS)

In this open-label study, a single dose of the corticosteroid Betamethasone Dipropionate Nasal Cream 0.0644% (equivalent to 0.05% Betamethasone) will be administered under endoscopic guidance to the sinus mucosa of post-FESS patients whose chronic rhinosinusitis (CRS) condition is suboptimal under the current standard of care. The safety and benefits of this treatment will be monitored by patient-reported symptoms and endoscopic assessment of the sinus mucosa.

Inclusion criteria

• Adult patients with a clinically confirmed diagnosis of CRS by an otolaryngologist (ENT) undergoing maximal medical therapy as part of their standard of care.
• Having undergone functional endoscopic sinus surgery (FESS) at least 6 months prior to enrolment.
• For each nostril, an endoscopic nasal polyp score of 0, 1, or 2 out of a maximum score of - (where 0= No polyps, 1= small polyps in the middle meatus not reaching below the inferior border of the middle turbinate , 2= nasal polyps reaching below the border of the middle turbinate, 3= large nasal polyps reaching the lower border of the inferior turbinate or nasal polyps medial to the middle turbinate, 4= large nasal polyps causing almost complete obstruction of the inferior nasal cavity) (Gevaert et al, 2023).
• Visible middle turbinates and access to the ethmoid sinuses for dosing as established via endoscopic examination.
• Participants must have a > 2 on the disease severity visual analogue scale (VAS) at screening and pre-treatment.
• Body weight: A minimum body weight >=40 kilograms (kg) and a BMI of ≤ 39 at the screening visit.
• Individuals of childbearing potential must use adequate birth control methods and not plan to get pregnant during the study.
• Informed consent: Willingness to give written informed consent and willingness to participate in and comply with the study.
• Age ≥18 but <80 years.

Exclusion criteria

• Subjects with known hypersensitivity or contraindications to betamethasone dipropionate, mometasone, or topical anaesthesia.
• Subjects with sino-nasal abnormalities, disease, or implanted devices that prevents the application of the therapy.
• Previous enrolment in this study.
• Subjects currently receiving systemic corticosteroid or have received systemic corticosteroid in the prior 4 weeks or receiving biologic therapy.
• Subjects with a history of glaucoma or cataracts or have an abnormal intraocular pressure (IOP) at screening or pre-treatment (abnormal IOP is defined as greater than 21 mm Hg).
• Subjects with acute sinusitis.
• Subjects with known immunodeficiency.
• Subjects with diabetes (Type 1).
• Subjects with cystic fibrosis.
• Pregnant subjects or subjects trying to get pregnant or currently lactating as the effect on human pregnancy is unknown.
• Subjects who are unable to give an informed consent because of mental illness, dementia or communication difficulties.
• Subjects with a Cushing's disease diagnosis within the previous 12 months.
• Severe septal deviation and or previous total resection of the middle turbinate.
• Any lab abnormality or underlying medical condition which, in the Investigator's opinion, should exclude the participant.
• Subjects who are unlikely to comply with study procedures, restrictions and requirements as determined by the investigator.