Safety and Efficacy of Celecoxib Versus Naproxen in the 6-Month Treatment of Knee Osteoarthritis (CLOAK)

This study has been completed.
Information provided by:
Pfizer Identifier:
First received: March 18, 2008
Last updated: April 22, 2008
Last verified: April 2008

To compare the safety and efficacy of celecoxib versus naproxen for the treatment of knee osteoarthritis

Condition Intervention Phase
Osteoarthritis, Knee
Drug: Celecoxib
Drug: Naproxen
Drug: Placebo
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Treatment
Official Title: A Randomized, Multicenter, Double-Blind, Double-Dummy Study Comparing the Efficacy and Tolerability of Once Daily Celebrex (Celecoxib) and Naproxen 500 mg Twice Daily in the 6-Month Treatment of Subjects With Osteoarthritis of the Knee

Resource links provided by NLM:

Further study details as provided by Pfizer:

Primary Outcome Measures:
  • Number of responders, defined as a 20% improvement from baseline in the The Western Ontario MacMaster (WOMAC)Questionnaire Total Score [ Time Frame: Month 6 ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Number of health care professional contacts [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
  • Patient's and Physician's Satisfaction with Current Arthritis Therapy [ Time Frame: Month 6 ] [ Designated as safety issue: No ]
  • Change in WOMAC Total Score from baseline [ Time Frame: Month 6 ] [ Designated as safety issue: No ]
  • Change in WOMAC Subscales from baseline [ Time Frame: Month 6 ] [ Designated as safety issue: No ]
  • Response in each WOMAC Subscale [ Time Frame: Month 6 ] [ Designated as safety issue: No ]
  • Change in Medical Outcome Study sleep scale from baseline [ Time Frame: Month 6 ] [ Designated as safety issue: No ]
  • Laboratory tests [ Time Frame: Month 6 ] [ Designated as safety issue: Yes ]
  • Vital signs [ Time Frame: Month 6 ] [ Designated as safety issue: Yes ]
  • Response in VAS [ Time Frame: Month 6 ] [ Designated as safety issue: No ]
  • Change in Patient's and Physician's Global Assessment of Pain from baseline [ Time Frame: Month 6 ] [ Designated as safety issue: No ]
  • Change in visual analog scale (VAS) from baseline [ Time Frame: Month 6 ] [ Designated as safety issue: No ]
  • Adverse events [ Time Frame: Throughout study ] [ Designated as safety issue: Yes ]
  • Change in Gastrointestinal (GI) Distress Scale from Week 1 [ Time Frame: Month 6 ] [ Designated as safety issue: No ]
  • Change in GI Distress Scale from time of discontinuation of study drug [ Time Frame: Month 6 ] [ Designated as safety issue: No ]
  • Receipt of prescription or over-the-counter gastroprotective agents or pain medications (off study drug) [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
  • Number of hospitalizations, emergency room visits, and procedures [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
  • Change in Work Limitation Questionnaire scale scores from baseline [ Time Frame: Month 6 ] [ Designated as safety issue: No ]
  • Physical examination [ Time Frame: Month 6 ] [ Designated as safety issue: Yes ]

Enrollment: 586
Study Start Date: March 2004
Study Completion Date: January 2005
Primary Completion Date: January 2005 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: A Drug: Celecoxib
200 mg oral capsule once daily for 6 months
Active Comparator: B Drug: Naproxen
500 mg oral capsule twice daily for 6 months
Placebo Comparator: C Drug: Placebo
Matched oral placebo for 6 months


Ages Eligible for Study:   40 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Osteoarthritis of the knee as defined by the American College of Rheumatology criteria in a flare state at baseline visit
  • Functional Capacity Classification of I-III

Exclusion Criteria:

  • Inflammatory arthritis or gout/pseudo-gout with an acute flare within the past 2 years (subjects with fibrositis or fibromyalgia will not be excluded)
  • Received acetaminophen within 24 hours of the baseline visit
  • Acute joint trauma at index joint within the past 3 months with active symptoms
  • History of gastrointestinal (GI) perforation, obstruction, or bleeding
  • Diagnosed or treated for GI ulcer within 60 days prior to first dose of study medication
  • Received corticosteroids or hyaluronic acid within certain timeframe before study
  Contacts and Locations
Please refer to this study by its identifier: NCT00643799

  Show 51 Study Locations
Sponsors and Collaborators
Study Director: Pfizer Call Center Pfizer
  More Information

Additional Information:
No publications provided

Responsible Party: Director, Clinical Trial Disclosure Group, Pfizer, Inc Identifier: NCT00643799     History of Changes
Other Study ID Numbers: A3191152
Study First Received: March 18, 2008
Last Updated: April 22, 2008
Health Authority: United States: Food and Drug Administration

Additional relevant MeSH terms:
Osteoarthritis, Knee
Joint Diseases
Musculoskeletal Diseases
Rheumatic Diseases
Anti-Inflammatory Agents, Non-Steroidal
Analgesics, Non-Narcotic
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Pharmacologic Actions
Anti-Inflammatory Agents
Therapeutic Uses
Antirheumatic Agents
Gout Suppressants
Cyclooxygenase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Central Nervous System Agents
Cyclooxygenase 2 Inhibitors processed this record on April 17, 2014