Biogen Idec's chief executive, James Mullen is not a happy man. The Cambridge biotechnology company is not likely to receive approval from European regulators to use its drug Tysabri to treat patients with Crohn's disease, a debilitating intestinal ailment.
Results from drug trials that were included in an application to the European Medicines Agency were marked as "interesting but need more development". Now, an additional clinical trial proposed by the agency could take years and cost Biogen Idec millions of dollars, says Mullen.
Biogen Idec and Elan Corp. of Ireland have partnered on development of Tysabri since 2001. After showing promising results in testing, the drug was introduced in the United States in November 2004 to treat patients with multiple sclerosis, but was abruptly withdrawn from the market after the companies found two patients in Tysabri trials had contracted a potentially fatal brain disease. Ultimately, three patients were found to have contracted the brain disease, progressive multifocal leukoencephalopathy, or PML, and two died from it.
Yet, after impassioned testimonies from multiple sclerosis patients anxious for a chance to try Tysabri, the Food and Drug Administration permitted sales to resume, but Biogen Idec was required to take additional safety precautions, including a mandatory registry of patients receiving the drug.
In recent public statements, officials from Biogen Idec and Elan touted Tysabri's ability to induce remission in Crohn's patients.
In their partnership, Biogen Idec has led trials and regulatory filings related to multiple sclerosis, and Elan has overseen the potential expansion of Tysabri as a treatment for Crohn's disease.
"The data suggest that Tysabri could be an alternative biologic choice for Crohn's disease patients," says Elan."As the data continue to unfold, [Elan and Biogen Idec] will explore additional indications, as appropriate, to unmet medical needs", the company was quoted.
In a comprehensive safety review last year, the companies found two multiple sclerosis patients with PML who were also being treated with Biogen Idec's drug Avonex, another treatment for multiple sclerosis. One of those patients survived. Another patient in a Crohn's trial, who died from PML, had been treated with immunosuppressants.
This pattern, according to experts, suggests that the risks of contracting PML while using Tysabri could increase if a patient is also being given a drug that affects the immune system. If so, that raises the risks of treating Crohn's patients with Tysabri, because many have weakened immune systems.
"Against the backdrop of PML, where you have a set of patients that already get bombarded with immunosuppressants over 20 to 30 years, [Crohn's] is not the first place we'd go to develop Tysabri," states Mullen. According to him, the drug looks more promising as a treatment for Lupus and certain cancers.