PANDORA: Evaluation of Platelet-rich Plasma in Non-tumoural Odour Disorders: a Descriptive Pilot Study. (PANDORA)

This is a prospective, single-center, single-arm, non-comparative descriptive pilot study evaluating autologous platelet-rich plasma (PRP) injections in adults with persistent (>6 months) non-tumoural olfactory dysfunction, either age-related degenerative olfactory dysfunction (DOD) or post-traumatic olfactory dysfunction (DOPT). Participants receive three PRP injections over 4 weeks (Day 0, Day 14, Day 28), with follow-up visits at Month 3 and Month 6 after the first injection. Olfactory function is assessed using the Sniffin' Sticks Test (TDI score). Patient-reported outcomes include SNOT-22 and a visual analog scale (VAS) for perceived olfactory impairment. Safety is assessed through adverse event collection.

Study Overview

• Status: Not yet recruiting
• Conditions: Olfactory Dysfunction; Post-traumatic Olfactory Dysfunction; Age-related Degenerative Olfactory Dysfunction
• Intervention / Treatment: Biological: Autologous Platelet-Rich Plasma (PRP) Injection

Detailed Description

Prospective consecutive recruitment in an ENT department at Hôpital Lyon Sud (Hospices Civils de Lyon). Eligible participants are enrolled into one of two diagnostic cohorts (DOD or DOPT), and analyses are performed separately by cohort. PRP is prepared from autologous venous blood using a standardized preparation system and injected under endoscopic guidance in the olfactory cleft area (superior nasal septum mucosa). Follow-up assessments are performed at baseline and at Months 3 and 6 after the first injection.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Maxime FIEUX, Dr; Phone Number: +33 0033 4 72 66 64 15; Email: maxime.fieux@chu-lyon.fr

Study Locations

• France
  • Pierre-Bénite, France, 69310
    • Hôpital Lyon Sud
    • Contact: Maxime FIEUX, Dr; Phone Number: +33 0033 4 72 66 64 15; Email: maxime.fieux@chu-lyon.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria

• Adults with persistent (>6 months) non-tumoural olfactory dysfunction: age-related degenerative olfactory dysfunction (DOD) or post-traumatic olfactory dysfunction (DOPT).
• Objective olfactory impairment confirmed by Sniffin' Sticks Test (TDI ≤ 30.5/48).
• MRI within the last 6 months after onset excluding tumoural etiology or central cause.
• Normal nasal endoscopy.
• Affiliated to a social security system (or equivalent).
• Written informed consent.

Exclusion Criteria

• Inflammatory rhinosinus disease (e.g., nasal polyposis) or granulomatosis with polyangiitis.
• Coagulation disorder.
• Brain radiotherapy history or ongoing chemotherapy.
• Olfactory disorder temporally linked to SARS-CoV-2 infection (delay <1 month).
• History of sinus or skull base surgery (except septoplasty/turbinoplasty/rhinoseptoplasty).
• Therapeutic-dose anticoagulants.
• Refusal to discontinue chronic NSAID use if applicable.
• Pregnancy/labor/breastfeeding.
• Vulnerable persons (deprived of liberty; legal protection; etc.).
• Participation in another interventional study with ongoing exclusion period.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: PRP injections; Single arm receiving autologous platelet-rich plasma injections at Day 0, Day 14 (±1), and Day 28 (±1), with follow-up at Months 3 and 6.

Biological: Autologous Platelet-Rich Plasma (PRP) Injection; At each injection visit (Day 0, Day 14 ±1, Day 28 ±1), venous blood is collected and processed to obtain autologous PRP using a standardized preparation system. PRP is injected under endoscopic guidance into the superior nasal septum mucosa near the olfactory cleft, up to a total volume of 4 mL per visit. Participants are monitored after each injection and adverse events are recorded.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of participants with clinically meaningful improvement in olfactory function (Sniffin' Sticks Test TDI score)	Proportion of participants whose change in olfactory function, measured using the Sniffin' Sticks Test (Threshold, Discrimination, Identification score - TDI), between baseline (Visit 1, prior to the first PRP injection) and the 6-month follow-up visit reaches or exceeds the minimal clinically significant difference (MCID) of 5.5 points on the 48-point TDI scale. The TDI score combines three components: olfactory threshold (T), odor discrimination (D), and odor identification (I).	Baseline (Visit 1, prior to first injection) to Month 6 follow-up (Visit 5)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Occurrence of treatment-related adverse events	ccurrence and type of adverse events during the study period. Adverse events will be classified according to the Common Terminology Criteria for Adverse Events (CTCAE v5.0). For each adverse event, the investigator will assess severity and relationship to the experimental treatment.	From first injection (Day 0) to Month 6 follow-up visit
Change in olfactory function at Month 3 (TDI score)	Change in olfactory function measured by the Sniffin' Sticks Test (TDI score) between baseline (Visit 1, before the first injection) and the Month 3 follow-up visit.	Baseline (Visit 1) to Month 3 follow-up (Visit 4)
Change in olfactory function at Month 6 (TDI score)	Change in olfactory function measured by the Sniffin' Sticks Test (TDI score) between baseline (Visit 1, before the first injection) and the Month 6 follow-up visit.	Baseline (Visit 1) to Month 6 follow-up (Visit 5)
Change in quality of life (SNOT-22 score)	Change in quality of life assessed using the Sino-Nasal Outcome Test (SNOT-22) questionnaire between baseline and Month 6. The SNOT-22 score ranges from 0 to 110, with higher scores indicating greater symptom burden. A minimal clinically significant difference is considered to be 8.9 points.	Baseline (Visit 1) to Month 6 follow-up (Visit 5)
Change in patient-reported olfactory impairment (Visual Analog Scale)	Change in patient-reported olfactory impairment assessed using a Visual Analog Scale (VAS) ranging from 0 (no discomfort) to 10 (unbearable discomfort) between baseline and Month 6.	Baseline (Visit 1) to Month 6 follow-up (Visit 5)

Collaborators and Investigators

• Sponsor: Hospices Civils de Lyon

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): May 1, 2028
• Study Completion (Estimated): May 1, 2028

Study Registration Dates

• First Submitted: March 11, 2026
• First Submitted That Met QC Criteria: March 11, 2026
• First Posted (Actual): March 16, 2026

Study Record Updates

• Last Update Posted (Actual): March 20, 2026
• Last Update Submitted That Met QC Criteria: March 17, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: PRP; Hyposmia; Platelet-rich plasma; Anosmia; Sniffin' Sticks; Olfactory cleft
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Sensation Disorders; Olfaction Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Anosmia; Therapeutics; Drug Administration Routes; Drug Therapy; Injections
• Other Study ID Numbers: 69HCL24_1192; 2025-A02847-42 (Other Identifier: ID RCB)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No