The COX-2 inhibitor celecoxib (Celebrex) has been shown to reduce the risk of developing new adenomatous polyps in patients who have previous polyps. The large trials studying this were stopped when the increased risk of cardiac problems came to light, but there was good evidence of effectiveness. An update on the two large trials was recently reported (AACR Meeting 2006)

Adenoma Prevention with Celecoxib (APC) Trial compared placebo to 200mg bid or 400mg bid. The interventional Prevention of Sporadic Colorectal Adenomatous Polyps Study (PreSAP) compared placebo with 400 mg once a day
APC Trial
Therapy New Polyp Reduction
placebo 61%  
200mg bid 41% -33%
400mg bid 35% -45%

APC Trial
Therapy High Risk  Polyp Reduction
placebo 26%  
200mg bid 11% -57%
400mg bid 9% -66%

Serious Cardiac Event in APC
Therapy No history Cardiac history
placebo 0.7% 3%
Celebrex 2% 9%

New Polyp in PreSAP
Therapy New Polyp Reduction
placebo 49%  
Celebrex 34% -33%

New High Risk Polyp in PreSAP
Therapy New High Risk Polyp Reduction
placebo 10%  
Celebrex 5% -49%

New Cardiac Event in PreSAP
Therapy Cardiac Event
placebo 5%
Celebrex 7.5%