Efficacy & Safety of OPN-375 Adults With Bilateral Nasal Polyps Using Nasoendoscopic Video

Inclusion Criteria: 1. Men or women aged 18 years and older at Visit 1 (Baseline/Day1) 2. Women of child bearing potential must be abstinent, or if sexually active, 1. be practicing an effective method of birth control (e.g., prescription oral contraceptives, contraceptive injections, contraceptive patch, intrauterine device, double-barrier method \[e.g., condoms, diaphragm, or cervical cap with spermicidal foam, cream, or gel\], or male partner sterilization) before entry and throughout the study, or 2. be surgically sterile (have had a hysterectomy or bilateral oophorectomy, tubal ligation, or otherwise be incapable of pregnancy), or 3. be postmenopausal (amenorrhea for at least 1 year). 3. Women of child-bearing potential must have a negative urine pregnancy test at Visit 1 (Day 1/Baseline) 4. Must have bilateral nasal polyposis with a grade of 2 or 3 in at least one side of the nasal cavity as determined by a nasal polyp grading scale score measured by nasoendoscopy at Visit 1 (Day 1/Baseline) 5. Must have a SNOT-22 score of ≥20 at Visit 1(Baseline/Day 1) 6. Must have been on an adequate dose of an intranasal corticosteroid (e.g. fluticasone propionate, fluticasone furoate, mometasone, triamcinolone, ciclosenide, budesonide, budesonide respules, beclomethasone) for at least 1 month, in the previous 3 months prior to Visit 1 (Day 1/Baseline) 7. Subjects with comorbid asthma or chronic obstructive pulmonary disease (COPD) must be stable with no exacerbations (e.g., no emergency room visits, hospitalization, or oral or parenteral steroid use) within the 3 months before the screening visit. Inhaled corticosteroid use must be limited to stable doses of no more than 1,000 μg/day of beclomethasone (or equivalent) for at least 3 months before screening with plans to continue use throughout the study 8. Must be able to cease treatment with oral steroids, intranasal steroids, inhaled corticosteroids (except permitted doses listed above for asthma and COPD) at Visit 1 (Day 1/Baseline) 9. Must demonstrate correct use of the demo EDS 10. Ability to read and speak English 11. Must be capable, in the opinion of the investigator, of providing informed consent to participate in the study. Subjects must sign an informed consent document indicating that they understand the purpose of and procedures required for the study and are willing to participate in the study Exclusion Criteria: 1. Women who are pregnant or lactating 2. Inability to have each nasal cavity examined for any reason, including nasal septum deviation 3. Have used XHANCE™ (fluticasone propionate) nasal spray within the past 2 months 4. Nasal septum perforation 5. Has had more than 1 episode of epistaxis with frank bleeding in the month before Visit 1 (Day 1/Baseline) 6. Have evidence of significant mucosal injury or ulceration (e.g. exposed cartilage) on Visit 1 (Day 1/Baseline) nasal examination/nasoendoscopy 7. History of sinus or nasal surgery within 3 months before Visit 1 (Day 1/Baseline). If \>3 months subject should be fully recovered from surgery 8. Current, ongoing rhinitis medicamentosa (rebound rhinitis) 9. Have significant oral structural abnormalities, e.g., a cleft palate 10. Diagnosis of cystic fibrosis 11. History of Churg-Strauss syndrome or dyskinetic ciliary syndromes 12. Purulent nasal infection, acute sinusitis, or upper respiratory tract infection within 2 weeks before Visit 1 (Day 1/Baseline). Potential subjects presenting with any of these infections may be rescreened 4 weeks after symptom resolution 13. Planned sinonasal surgery during the period of the study 14. Allergy, hypersensitivity, or contraindication to corticosteroids, steroids, or to any excipients in OPN-375 15. Exposure to any glucocorticoid treatment with potential for systemic effects (e.g., oral, parenteral, intra-articular, or epidural steroids, high dose topical steroids) within 1 month before Visit 1 (Day 1/Baseline); except as noted in inclusion criteria for subjects with comorbid asthma or COPD 16. Have nasal candidiasis at Visit 1 (Day 1/Baseline) 17. History or current diagnosis of any form of glaucoma, ocular hypertension, or intraocular pressure elevation on any form of steroid therapy 18. History or current diagnosis of the presence (in either eye) of a sub-capsular cataract 19. Any serious or unstable concurrent disease, psychiatric disorder, or any significant condition that, in the opinion of the investigator could confound the results of the study or could interfere with the subject's participation or compliance in the study 20. Recent (within 1 year of Visit 1 (Day 1/Baseline)) history of drug or alcohol abuse, or dependence that, in the opinion of the investigator could interfere with the subject's participation or compliance in the study 21. Have participated in an investigational drug clinical trial within 30 days of Visit 1 (Day 1/Baseline) 22. Employees of the investigator or study center, with direct involvement in the proposed study or other studies under the direction of that investigator or study center, as well as family members of the employees or the investigator