Like drugs such as infliximab (Remicade) and adalimumab (Humira), certolizumab works by blocking a chemical called tumor necrosis factor. However, certolizumab is constructed a bit differently and is less likely to destroy certain immune cells.

The two studies, Pegylated Antibody Fragment Evaluation in Crohn's Disease: Safety and Efficacy (PRECISE) trials 1 and 2, evaluated the use of certolizumab pegol in 638 adults with moderate-to-severe disease who were followed for 26 weeks, lead author Dr. William J. Sandborn, from the Mayo Clinic in Rochester, Minnesota, and colleagues note.

The studies were funded, in part, by UCB Pharma, which hopes to market the drug as CIMZIA.

According to a related editorial by Dr. James D. Lewis, from the University of Pennsylvania in Philadelphia, the studies shared many features, but had one key difference. PRECISE 1 focused on certolizumab as the initial treatment, whereas PRECISE 2 examined the drug as continued therapy for patients who already showed a treatment response.

In PRECISE 1, patients given certolizumab at weeks 0, 2, 4 and then every 4 weeks had significantly higher response rates at weeks 6 and 26 compared with patients who were given a placebo.

By contrast, no significant differences were seen between the groups in remission rates at week 26. Serious side effects, including infections, were uncommon with certolizumab and occurred with similar frequency as with placebo.

The findings from PRECISE 2 suggest that continued certolizumab therapy is effective in maintaining the treatment response and achieving remission.

While the current findings are encouraging, certolizumab may not be the most effective anti-tumor necrosis factor drug for patients with Crohn's disease, Lewis suggests in his editorial.

Ideally, a clinical trial comparing the various drugs should be conducted, but unfortunately this is unlikely to happen, he adds. "Rather, the choice of therapy will probably be driven by other factors, such as perceived relative effectiveness, economics, and convenience for patients," he concludes.

SOURCE: The New England Journal of Medicine, July 19, 2007.

Copyright © 2007 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.