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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   (Adult, Senior)
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
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00643799

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Sponsors and Collaborators
Study Director: Pfizer Call Center Pfizer
  More Information

Additional Information:
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
Cyclooxygenase 2 Inhibitors
Cyclooxygenase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Anti-Inflammatory Agents, Non-Steroidal
Analgesics, Non-Narcotic
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Anti-Inflammatory Agents
Antirheumatic Agents
Gout Suppressants processed this record on December 05, 2016