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Completed

NCT Number: NCT03146689

Ibuprofen Gel or Capsaicin Cream for my Painful Knee Osteoarthritis?

Despite evidence that topical non-steroidal anti-inflammatory drugs (NSAIDs) and capsaicin are effective in osteoarthritis (OA), it is still unclear why they work for some people but not others. The investigators are undertaking an individual patient data (IPD) meta-analysis to identify responders according to patient characteristics, however, no studies report the presence of synovial hypertrophy or neuropathic-like pain. These two traits are of interest as they may be used to optimise the treatment effects of the two drugs which work via different mechanisms to reduce pain in OA. The investigators are therefore conducting this pilot n-of-1 trial series.

This pilot n-of-1 trial series will investigate whether a person with OA, who has a different balance between inflammatory and neuropathic pain, shows a preference between these mechanistically different treatments. The trial will also be used to offer recommendations on the use of n-of-1 trial series for individualised (precision) medicine in OA.

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Key information

Conditions

Osteoarthritis, Knee Arthritis Joint Diseases Musculoskeletal Diseases Osteoarthritis Rheumatic Diseases

Age range

40 year–95 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Academic Rheumatology, University of Nottingham

Nottingham, Nottinghamshire, NG5 1PB, United Kingdom

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Men and non-pregnant women who have had ultrasound and radiographic assessments in the Knee Pain in the Community study

o Premenopausal women will need to be on an acceptable contraceptive method

  • Aged 40-95 years
  • Knee pain between 4-8 on the NRS
  • Knee osteoarthritis - defined as knee pain plus radiographic changes, based on previous questionnaire responses and radiographic findings
  • Knee pain: individuals with knee pain in and around the knee on most days for at least a month.
  • Radiographic changes: definite joint space narrowing and definite osteophytes (each scoring two or more on the Nottingham Line Drawing Atlas) in the tibiofemoral and/or patellofemoral compartments
  • Predominantly neuropathic or inflammatory phenotypes based on previous questionnaire responses (not current status)
  • Predominantly neuropathic phenotype: painDETECT Questionnaire (PDQ) > 13 and synovial hypertrophy (SH) <4 mm
  • Predominantly inflammatory phenotype: SH > 4 mm and PDQ < 13
  • If we cannot recruit enough people with the above thresholds, we will base recruitment on the overall distribution of PDQ and SH scores from the population. The third tertile of PDQ and the first tertile of SH for neuropathic and the first tertile of PDQ and the third tertile of SH for inflammatory phenotypes.

Exclusion criteria

  • Inability to give informed consent
  • Daily use of oral NSAIDs for the last two weeks
  • Prior use of Ibuprofen gel or Zacin on the affected knee(s)
  • Terminal or untreated major mental illness
  • Pregnancy or breastfeeding
  • Hypersensitivity or allergy to topical NSAIDs, capsaicin, or other ingredients in the preparations. This includes individuals that experience attacks of asthma, urticaria, or acute rhinitis that are precipitated by NSAIDs
  • Current treatment for stomach or duodenal ulcers
  • Total joint replacement of affected joint
  • Renal failure
  • Taking anticoagulants

Treatment and study plan

Topical NSAID

Drug

Applied four times daily

Other names: Ibuprofen 5% gel

Topical Capsaicin

Drug

Applied four times daily

Other names: Zacin 0.025% cream

Primary outcomes

  1. Change from baseline knee pain on 0-10 numeric rating scale (NRS)

    Time frame: Baseline and end of each treatment period (i.e., after four weeks of treatment)

    Pain experienced in the most painful knee in the past week will be recorded. The following question will be asked for this purpose: "In the past week, on average, how intense was your knee pain rated on a 0-10 scale, where 0 is 'no pain' and 10 is 'pain as bad as could be'?". The change in pain score between period baseline and period end will be calculated

Secondary outcomes

  1. End-of-cycle treatment preference

    Time frame: At the end of each treatment cycle (i.e., after 4 weeks of NSAID and 4 weeks of capsaicin).

    "Considering only the pain relief experienced in this most recent cycle, which treatment do you feel provided satisfactory pain relief?"

  2. End-of-study overall treatment preference

    Time frame: At study completion - following six treatment periods (24 weeks of treatment, excluding washouts) or 4 treatment periods for responders at the interim analysis (16 weeks of treatment, excluding washouts)

    "Considering all the aspects of the treatment, including its effectiveness and ease of application, which treatment do you prefer?"

  3. Weekly knee pain on 0-10 numeric rating scale (NRS)

    Time frame: At end of week 1, week 2, week 3, and week 4 of each treatment period.

    Pain experienced in the most painful knee in the past week will be recorded. The following question will be asked for this purpose: "In the past week, on average, how intense was your knee pain rated on a 0-10 scale, where 0 is 'no pain' and 10 is 'pain as bad as could be'?".

Sponsors and collaborators

Lead sponsor

University of Nottingham

Other

Collaborators

  • Arthritis Research UK Pain Centre
  • Nottingham University Hospitals NHS Trust

Registry information

Official study title

Identifying Treatment Responders to a Topical Non-steroidal Anti-inflammatory Drug (NSAID) or Topical Capsaicin in Painful Knee Osteoarthritis: A Pilot Series of N-of-1 Trials

Important dates

Study start
2017
Primary completion
2018
Study completion
2018
First posted
May 10, 2017
Registry last updated
Apr 18, 2019

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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