The U.S. Food and Drug Administration has approved Tysabri (natalizumab) for the treatment of moderate-to-severe Crohn's disease in patients with evidence of inflammation who have had an inadequate response to, or are unable to tolerate, conventional Crohn's disease therapies.
Crohn's disease patients using the drug must be enrolled in a special restricted distribution program called the Crohn's Disease–Tysabri Outreach Unified Commitment to Health (CD TOUCH) Prescribing Program.
The approval is consistent with an agency advisory committee recommendation to approve Tysabri for use in Crohn's patients. Tysabri was approved by the FDA in June 2006 to treat relapsing forms of multiple sclerosis.
Crohn's disease is a chronic, inflammatory bowel disease that affects both men and women. There is no cure. Crohn's can cause diarrhea, fever, rectal bleeding, malnutrition, narrowing of the intestinal tract, obstructions, abscesses, cramping, and abdominal pain. The disease also can lead to abnormal connections (fistulas) leading from the intestine to the skin or internal organs. Its cause is unknown. There are more than 1 million people with Crohn's disease worldwide.
"The addition of Tysabri to the treatment options for sufferers of Crohn's disease is important, but one that carries serious risks," said Daniel Shames, deputy director of the Office for Drug Evaluation III and director of the Division of Gastroenterology Products for the Center for Drug Evaluation and Research. "Health care providers must carefully monitor patients for these risks. The CD-TOUCH Prescribing Program will aid FDA in monitoring this drug through its life cycle."
Tysabri carries a boxed warning for progressive multifocal leukoencephalopathy (PML), an opportunistic viral infection that affects the brain and can lead to death or severe disability.
Other serious adverse events that have occurred in Tysabri-treated patients include hypersensitivity reactions, such as anaphylaxis and liver injury. Serious opportunistic and other atypical infections have been observed in patients receiving immunosuppressants while on Tysabri, and Tysabri should generally not be used in patients receiving immunosuppressants. Serious herpes infections have also been observed. Common side effects include headache, fatigue, infusion reactions, urinary tract infections, joint and limb pain, and rash.
Because of these risks, patients, prescribers, pharmacies, and infusion centers must all be enrolled in CD-TOUCH and agree to comply with the company's strict monitoring guidelines. Additionally, they must participate in an extensive educational program designed to inform people about the risks of Tysabri treatment. Tysabri is administered intravenously by trained professionals at infusion centers.
Under CD-TOUCH, health care providers evaluate Crohn's disease patients after three months of treatment to determine if they have improved on Tysabri. If not, patients should discontinue treatment. People who are taking steroids for Crohn's disease should begin tapering steroid doses while on Tysabri. Treatment should be discontinued if steroids cannot be fully tapered within six months.
Tysabri is manufactured by Biogen Idec of Cambridge, Massachusetts and Elan of Dublin, Ireland. Both companies have agreed to conduct long-term surveillance for safety, including monitoring and expedited reporting of PML infections, other serious opportunistic infections, malignancies, and deaths in people treated with Tysabri.