Diphenhydramine Ointment for Knee Osteoarthritis

Study Overview
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Brief Summary
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The main purpose of this study is to evaluate whether recruitment rates are adequate to power a future RCT. The secondary aims are to obtain preliminary information about safety and efficacy of topical diphenhydramine 5% ointment in patients with knee OA.

Official Title
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Diphenhydramine 5% Ointment for Pain in Knee Osteoarthritis: a Randomised Double-blind Placebo-controlled Pilot Feasibility Study

Conditions
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Osteoarthritis

Intervention / Treatment
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* Drug: Diphenhydramine 5%
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ACR clinical criteria of knee OA Radiographic knee OA (Kellgren-Lawrence grade >1) Age ≥ 50 years VAS pain >= 40/100 mm at baseline Non-use of NSAIDs one week before the baseline Symptoms present on most days for at least 3 months Exclusion Criteria: Any form of inflammatory arthritis Use of another topical product at the application site Treatment with intraarticular hyaluronic acid within 6 months Treatment with intraarticular glucocorticoid within 2 months Knee injury/surgery or diagnostic arthroscopy within 3 months Allergic reaction to diphenhydramine or any component of the formulation Participant has clinical signs and symptoms suggestive of COVID-19, eg, fever, dry cough, dyspnea, sore throat, fatigue or confirmed infection by appropriate laboratory test within the last 4 weeks prior to Screening

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Diphenhydramine<br>Topical 5% diphenhydramine ointment applied at knee joint at a dose of 2 g three times a day for 7 days | Drug: Diphenhydramine 5%<br>* Diphenhydramine 5% ointment<br>|
| Placebo Comparator: Placebo<br>Vehicle (placebo) ointment applied at knee joint at a dose of 2 g three times a day for 7 days | Drug: Placebo<br>* Placebo matched to diphenhydramine 5% ointment<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Recruitment rates | Ability to recruit 8 patients per month | through study completion, an average of 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Refusal rate | Number of eligible patients who refuse to participate | through study completion, an average of 1 year | 
| Adherence | Number of patients adhering to 80% of allocated treatment | through study completion, an average of 1 year | 
| Visual Analogue Scale for Pain | The Visual Analogue Scale for Pain varies from 0 to 10 cm. Higher values represent worse outcomes. | Baseline to week 1 | 
| Knee injury and Osteoarthritis Outcome Score (KOOS) - subscale Pain | KOOS Pain consists of 9 items, which are answered on a 4-point likert scale (0=no problems, 4=extreme problems). Scores are transformed to a 0-100 scale, with zero representing extreme knee problems and 100 representing no knee problems.. | Baseline to week 1 | 
| Knee injury and Osteoarthritis Outcome Score (KOOS) - subscale Symptoms | KOOS Symptoms consists of 7 items, which are answered on a 4-point likert scale (0=no problems, 4=extreme problems). Scores are transformed to a 0-100 scale, with zero representing extreme knee problems and 100 representing no knee problems. | Baseline to week 1 | 
| Knee injury and Osteoarthritis Outcome Score (KOOS) - subscale Activities of daily living (ADL) | KOOS ADL consists of 17 items, which are answered on a 4-point likert scale (0=no problems, 4=extreme problems). Scores are transformed to a 0-100 scale, with zero representing extreme knee problems and 100 representing no knee problems. | Baseline to week 1 | 
| Knee injury and Osteoarthritis Outcome Score (KOOS) - subscale of function in sports and recreation (Sport/Rec) | KOOS Sport/Rec consists of 5 items, which are answered on a 4-point likert scale (0=no problems, 4=extreme problems). Scores are transformed to a 0-100 scale, with zero representing extreme knee problems and 100 representing no knee problems. | Baseline to week 1 | 
| Knee injury and Osteoarthritis Outcome Score (KOOS) - subscale of quality of life (QOL) | KOOS QOL subscale of quality of life consists of 4 items, which are answered on a 4-point likert scale (0=no problems, 4=extreme problems). Scores are transformed to a 0-100 scale, with zero representing extreme knee problems and 100 representing no knee problems. | Baseline to week 1 | 
| Visual Analogue Scale for patient global assessment | The Visual Analogue Scale for patient global assessment varies from 0 to 10 cm. Higher values represent worse outcomes. | Baseline to week 1 | 
| Global evaluation of treatment by patient | Global evaluation of treatment by patient on 5 point Likert scale. The Global Evaluation of treatment varies from 0 to 5. Higher values represent worse outcomes. | Baseline to week 1 | 
| Percentage of patients achieving minimal clinically important improvement (MCII) of visual analogue scale (VAS) pain | Percentage of patients achieving MCII of VAS pain. The cut-off for MCII changes will be 15 of 100 for absolute improvement and 20% for relative improvement | Week 1 | 
| Percentage of patients achieving minimal clinically important improvement (MCII) of visual analogue scale (VAS) patient's global assessment | Percentage of patients achieving MCII of VAS patient's global assessment The cut-offs for MCII changes will be 15 of 100 for absolute improvement and 20% for relative improvement for patient's global assessment | Week 1 | 
| Percentage of patients achieving minimal clinically important improvement (MCII) of Knee injury and Osteoarthritis Outcome Score (KOOS) function of daily living | Percentage of patients achieving MCII of Knee injury and Osteoarthritis Outcome Score (KOOS) subscale of function of daily living. The cut-offs for MCII changes will be 8 of 100 for absolute improvement for KOOS function in daily living subscale score | Week 1 | 
| Adverse events | Any adverse event occurred during the study | Baseline to Week 1 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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osteoarthritis, knee, pain, antihistamines