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OPN-375

Phase 4

Bilateral Nasal Polyposis | Small molecule | ENT |OptiNose, Inc.|Trials Updated: Sep 18, 2026

OPN-375 development status

Highest phase Phase 4 run by GlaxoSmithKline (NCT00169546)
Phase scored for OPTNPhase 3
Registered trials 55 across 16 sponsors since Jul 2005

OPN-375 target and mechanism

ModalitySmall molecule

Also known as Fluticasone propionate

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLED
Total Trials4
Total Enrollment679

FDA Designations

No designations recorded

OPN-375 clinical trials

OPN-375 · 4 trials · 3 indications

Phase 3 4
NCT06850805Efficacy and Safety of 186 mcg of OPN-375 Nasal Spray Twice a Day (BID) in Adolescents With Chronic Rhinosinusitis Without Nasal PolypsChronic Rhinosinusitis Without Nasal Polyps
RECRUITING84 Analytics
NCT03960580Study Evaluating the Efficacy and Safety of Intranasal Administration of OPN-375 in Subjects With Chronic Rhinosinusitis Without the Presence of Nasal PolypsChronic Rhinosinusitis
COMPLETED223 Analytics
NCT03747458OPN-375 Efficacy and Safety in Adolescents With Bilateral Nasal PolypsBilateral Nasal Polyposis
COMPLETED40 Analytics
NCT03781804Study Evaluating the Efficacy and Safety of Intranasal Administration of OPN-375 in Subjects With Chronic Rhinosinusitis With or Without the Presence of Nasal PolypsChronic Rhinosinusitis
COMPLETED332 Analytics
PHASE3RECRUITING
Efficacy and Safety of 186 mcg of OPN-375 Nasal Spray Twice a Day (BID) in Adolescents With Chronic Rhinosinusitis Without Nasal Polyps
Chronic Rhinosinusitis Without Nasal PolypsUnlock trial analytics
PHASE3COMPLETED
Study Evaluating the Efficacy and Safety of Intranasal Administration of OPN-375 in Subjects With Chronic Rhinosinusitis Without the Presence of Nasal Polyps
Chronic RhinosinusitisUnlock trial analytics
PHASE3COMPLETED
OPN-375 Efficacy and Safety in Adolescents With Bilateral Nasal Polyps
Bilateral Nasal PolyposisUnlock trial analytics
PHASE3COMPLETED
Study Evaluating the Efficacy and Safety of Intranasal Administration of OPN-375 in Subjects With Chronic Rhinosinusitis With or Without the Presence of Nasal Polyps
Chronic RhinosinusitisUnlock trial analytics

Study Endpoints

Primary Endpoints

Change from baseline to the end of Week 4 in the average instantaneous CSS (evaluation of symptom severity immediately preceding the time of scoring).
4 Weeks

The CSS consists of the sum of the scores (0-3) assigned to each of the following symptoms of CRS: nasal congestion, nasal discharge (anterior and/or posterior), facial pain/pressure sensation, where 0 = no symptoms, 1 = mild symptoms, 2 = moderate symptoms, and 3 = severe symptoms. The total CSS for each day can range from 0 to 9. Participants will report symptom severity immediately preceding the time of scoring every morning (AM). The baseline CSS is the average of the CSS's over the last 7 days of the single-blind run-in period. The end of Week 4 CSS is the average of the CSS's over the 7 days before Week 4.

Change From Baseline in Symptoms as Measured by a Composite Score for Each Symptom of Nasal Congestion, Facial Pain or Pressure Sensation, and Nasal Discharge (Anterior and/or Posterior) at the End of Week 4
4 Weeks

Change from baseline to the end of Week 4 in average total instantaneous AM scores (evaluation of symptom severity immediately preceding the time of scoring) for each symptom: nasal congestion, nasal discharge (anterior and/or posterior), facial pain/pressure sensation. Baseline scores are the averaged total instantaneous AM scores over the last 7 days of the single blind run in period, and the end of Week 4, scores are averaged over the 7 days from the subject diary. Range of scores for each nasal symptom is 0= none, 1 = mild, 2 = moderate, 3 = severe. Composite score is a sum of the 3 symptom scores and will range from 0 to 9.

Change From Baseline to Week 24/Early Termination (ET) in the Average Percent of the Volume Opacified (APOV) in the Ethmoid and Maxillary Sinuses.
Baseline, Week 24

Change from baseline to Week 24/ET in the average percent of ethmoid and maxillary sinus volume opacified as measured by CT. Percent volume opacified can range from 0% to 100%. Outcome measure is the percentage change from percent opacification at baseline to percent opacification at Week 24; therefore, change in opacification volume can range from -100% to 100%. For example, if Baseline opacification was 68.22% and Week 24 opacification was 66.11%, then the change would be reported as -2.11%.

Change in nasal congestion/obstruction symptoms (mild, moderate, severe) at the end of Week 4
4 Weeks

Change in nasal congestion/obstruction symptoms at the end of Week 4 measured by the 7-day average instantaneous morning (AM) diary symptom scores (ADS7-IA). The nasal symptom scale is what is used to score the nasal congestion/obstruction score, which is recorded in the diary. Nasal symptom scale is graded on a scale of 0=no symptom, 1=mild symptom, 2=moderate symptom, 3=severe symptom.

Mean change from baseline at Week 16 in total polyp grade
16 Weeks

Change in total polyp grade (sum of scores from both nasal cavities) at Week 16 as determined by a nasal polyp grading scale score measured using a 0 to 6 point severity grading scale, with 0 (no polyps) to 3 (severe polyps) points per nostril

Change From Baseline to Week 24/Early Termination (ET) in the Average Percent of the Volume Opacified in the Ethmoid and Maxillary Sinuses
Baseline, Week 24

Change from baseline to Week 24/ET in the average percent of ethmoid and maxillary sinus volume opacified as measured by CT. Percent volume opacified can range from 0% to 100%. Outcome measure is the percentage change from percent opacification at baseline to percent opacification at Week 24; therefore, change in opacification volume can range from -100% to 100%. For example, if Baseline opacification was 68.22% and Week 24 opacification was 66.11%, then the change would be reported as -2.11%.

Secondary Endpoints

Frequency of acute exacerbations of CRS over the 12-week treatment period
12 weeks
Change from baseline to the end of Week 4 on CSS score in subjects using an intranasal steroid treatment for CRS within 30 days of Visit 1/Screening
4 Weeks
Change from baseline to the end of Weeks 8 and 12 in CSS
8 Weeks; 12 Weeks
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Study Design & Arms

AllocationRANDOMIZED
MaskingDOUBLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Placebo BIDPLACEBO_COMPARATORDouble-Blind Treatment Phase: Intranasal administration of matching placebo BID x 12 weeks
OPN-375 186 µg BIDACTIVE_COMPARATORDouble-Blind Treatment Phase: Intranasal administration of OPN-375 186 µg x 12 weeks
OPN-375 186 μg BIDACTIVE_COMPARATOROPN-375 186 μg BID x 24 Weeks
OPN-375 372 μg BIDACTIVE_COMPARATOROPN-375 372 μg BID x 24 Weeks
PlaceboPLACEBO_COMPARATORMatching Placebo BID x 24 Weeks

Interventions

NameTypeDescription
OPN-375DRUGOPN-375 (fluticasone propionate) delivered via exhalation delivery system (EDS) BID
PlaceboDRUGPlacebo solution administered via exhalation delivery system (EDS).
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Eligibility Criteria

Age Range12 Years to 17 Years
SexALL
Healthy VolunteersNo
Study Sites24

Inclusion Criteria: 1. Male or female subjects aged 12 to 17 years, inclusive, at time of Visit 1 (Screening) 2. Female subjects, if sexually active, must: 1. be practicing an effective method of birth control (e.g., prescription oral contraceptives, contraceptive injections, contraceptive patc...

Countries:United StatesAustraliaBulgariaCzechiaGeorgiaNew ZealandPolandRomaniaSpainUnited KingdomArgentinaCanadaRussiaSweden
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Recent Changes (Last 90 Days)

MEDIUMOct 19, 2026NCT03747458TRIAL_REMOVED: changed
MEDIUMOct 19, 2026NCT03747458TRIAL_REMOVED: changed
LOWSep 19, 2026NCT06850805lastUpdatePostDate: changed
HIGHSep 19, 2026NCT03747458Status: ACTIVE_NOT_RECRUITING → COMPLETED
LOWSep 19, 2026NCT06850805lastUpdatePostDate: changed
HIGHSep 19, 2026NCT03747458Status: ACTIVE_NOT_RECRUITING → COMPLETED
LOWSep 19, 2026NCT06850805lastUpdatePostDate: changed
HIGHSep 19, 2026NCT03747458Status: ACTIVE_NOT_RECRUITING → COMPLETED

Frequently asked questions about OPN-375

What is OPN-375?

OPN-375 is an investigational small molecule nasal spray developed by OptiNose, Inc. (ticker OPTN). It is being studied for chronic rhinosinusitis, including chronic rhinosinusitis without nasal polyps and bilateral nasal polyposis. It is in Phase 3 clinical development and has not been approved by the FDA.

What is OPN-375 used for?

OPN-375 is being developed to treat chronic rhinosinusitis, including chronic rhinosinusitis without nasal polyps and bilateral nasal polyposis. Clinical trials have enrolled adolescents and adults with these conditions. It remains investigational and is not approved for commercial use.

Who makes OPN-375?

OPN-375 is developed by OptiNose, Inc., which trades under the ticker OPTN. The company is the sponsor of the Phase 3 clinical program evaluating the intranasal small molecule in chronic rhinosinusitis and bilateral nasal polyposis.

What phase is OPN-375 in?

OPN-375 is in Phase 3 clinical development. One Phase 3 trial, NCT06850805, is currently recruiting adolescents with chronic rhinosinusitis without nasal polyps, while three other Phase 3 studies have been completed. The drug is investigational and has not been approved by the FDA.

What clinical trials is OPN-375 in?

OPN-375 has been evaluated in Phase 3 trials including NCT06850805, which is recruiting adolescents with chronic rhinosinusitis without nasal polyps, and the completed studies NCT03960580, NCT03781804, and NCT03747458. These trials enrolled adults and adolescents across the United States, Europe, and other regions.

Is OPN-375 FDA approved?

OPN-375 is not FDA approved. It is an investigational small molecule in Phase 3 clinical development for chronic rhinosinusitis and bilateral nasal polyposis, sponsored by OptiNose, Inc. (ticker OPTN). Approval status would depend on completion of the clinical program and regulatory review.