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SAT0051 Cox-2 specific inhibition with mk-0663 120 mg q. d. over 4 weeks did not increase faecal blood loss: a controlled study with placebo and ibuprofen 800 mg t.i.d
  1. RH Hunt1,
  2. P Callegari2,
  3. B Bowen3,
  4. C James1,
  5. J Marshall1,
  6. E Mortensen2,
  7. A Cagliola2,
  8. C Yu2,
  9. H Quan2,
  10. T Simon2
  1. 1Division of Gastroenterology
  2. 2Clinical Research, Gastroenterology, Merck Research Laboratories, West Point, USA
  3. 3Department of Radiology, McMaster University Medical Centre, Hamilton, Canada


Background Treatment with existing NSAIDs is associated with increased gastrointestinal microbleeding. We conducted a double-blind, single centre study in 62 healthy volunteers (age 19–33 years) to test the hypothesis that faecal blood loss with MK-0663 (a new highly selective COX-2 inhibitor with a selectivity ratio of >100 in human whole blood assay) would be equivalent to placebo and superior to ibuprofen.

Objectives To compare faecal blood loss in volunteers taking MK-0663, ibuprofen, or placebo.

Methods Subjects were injected with 51Cr labelled red blood cells and daily faecal blood loss in collected stool was measured by a large sample counter. Subjects with normal faecal blood loss during a 1-week placebo baseline period were randomised to MK-0663 120 mg q.d., ibuprofen 800 mg t.i.d. or placebo treatment for 28 days. The effects of MK-0663 and placebo were compared by a predefined similarity bound for determination of equivalence.

Results The mean daily faecal blood loss (mL/day) over time is shown in the table below. MK-0663 (120 mg) was equivalent to placebo and caused less blood loss than ibuprofen. All treatments were generally well tolerated.

Abstract SAT0051 Table 1

Conclusion In this study, the highly selective COX-2 inhibitor, MK-0663, at a dose twice that maximally effective in osteoarthritis, was equivalent to placebo, whereas a therapeutic dose of ibuprofen significantly increased faecal blood loss.

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