Low molecular weight heparin (tinzaparin) vs. placebo in the treatment of mild to moderately active ulcerative colitis

Background: Heparin has anti-inflammatory and immunomodulatory activity which may be of therapeutic benefit in the treatment of ulcerative colitis. Aim: To test whether low molecular weight heparin, given subcutaneously, would provide a significant therapeutic response compared with placebo in the treatment of mild to moderate ulcerative colitis. Study design: A prospective, double-blind, randomized, placebo-controlled, multi-centre trial comparing tinzaparin 175 anti-Xa IU/kg/day (innohep, LEO Pharma) subcutaneously for 14 days followed by tinzaparin 4500 anti-Xa IU/day subcutaneously for 28 days with placebo, administered subcutaneously once daily for up to 42 days. The primary outcome measure was the mean change in colitis activity from baseline to the end of study treatment assessed by the sum of scores of stool frequency, rectal bleeding, sigmoidoscopic appearance and histology. Secondary outcome measures included changes in individual activity indices and laboratory parameters. Patients were assessed at weekly intervals for 6 weeks and within 1 week of completing treatment. Results: One hundred patients with active ulcerative colitis (up to six bloody stools per day, no fever, no tachycardia or systemic disturbances) were randomized. Forty-eight received tinzaparin and 52 received placebo. The difference in the mean percentage change in colitis activity from baseline to end of treatment (tinzaparin-placebo) was not statistically significant (P = 0.84). There was no difference between tinzaparin and placebo in any secondary outcome measure. One major bleed (rectal), occurred in a patient receiving placebo. Conclusion: This is the largest trial to date of heparin in ulcerative colitis. The results show no benefit of low molecular weight heparin over placebo in mild to moderately active ulcerative colitis.