(Reuters) - An experimental drug for ulcerative colitis and Crohn's disease from Takeda Pharmaceutical Co could pose risk of a potentially fatal brain infection called PML even though the problem has not been seen in clinical trials, staff members of the U.S. Food and Drug Administration said on Thursday.
Documents about the monoclonal antibody, called Entyvio, were released by the FDA staff ahead of a planned meeting on Monday among a panel of outside medical experts who will review the safety and effectiveness of the medicine and make recommendations to the FDA.
Japanese drugmaker Takeda earlier this year filed for marketing approval of Entyvio, whose chemical name is vedolizumab, in the United States and Europe.
Some 3,326 patients have received one or more infusions of the medicine in its various clinical trials, with no cases of the brain infection seen, the FDA staff said in a lengthy review document meant to flag potential concerns to the panel of outside medical experts.
A larger database of safety information would better enable reviewers to assess the PML risk, the document said.
The document expressed concern that PML, formally known as progressive multifocal leukoencephalopathy, has been seen in a drug that works through a similar mechanism: Biogen Idec Inc's Tysabri treatment for multiple sclerosis.
The FDA staff noted, however, that Tysabri's risk of causing PML may be partly due to the fact it is often taken over long periods and among patients that have been previously treated with drugs that suppress the immune system.
There have been 12 deaths in patients who have received Entyvio, none of which have been linked to the injectable drug, according to the briefing document.
The FDA staff questioned whether the benefit of Entyvio outweighs its risks, especially the risk of PML, and whether risk management strategies to prevent PML may be needed if the drug is approved.
Crohn's disease and ulcerative colitis are common forms of inflammatory bowel disease, and can cause discomfort, diarrhea, bleeding and other problems.
Entyvio is a monoclonal antibody meant to control inflammation by blocking a receptor, or protein, called alpha4beta7 integrin.
(Reporting by Ransdell Pierson; Editing by Nick Zieminski)