Fourth Case of Tysabri-related PML is Reported to FDA by Manufacturer

A fourth patient taking the multiple sclerosis drug Tysabri may have contracted a deadly brain disease called progressive multifocal leukoencephalopathy, or PML, calling into doubt a recent prediction that Tysabri will return to the U.S. market.

The FDA gave Tysabri so-called "fast track" approval in November 2004 to treat multiple sclerosis, a debilitating and incurable disease that can cause sudden partial paralysis. Tysabri was withdrawn from the market on February 28, 2005 after two MS patients taking Tysabri contracted the rare and usually fatal brain disease called progressive multifocal leukoencephalopathy, or PML; one of those patients eventually died.  In March 2005, a third patient — who was taking the drug to combat Crohn’s disease, a bowel disorder, rather than MS — died of PML.

The Boston Globe reported on June 1, 2005 that Biogen Idec Inc. — which, along with Elan Corp., developed Tysabri as a MS treatment — had recently told the FDA that a fourth patient may have contracted PML.  Elan declined to confirm or deny the report of this latest Tysabri-related PML case, asserting that it did not comment on "rumors" or individual cases going through the safety evaluation process.  The Boston Globe, however, stuck by its story and quoted an FDA spokeswoman as saying the agency was "in communications with on this case, as well as on the ongoing safety review."  Further, this Boston Globe report included the observation that because PML was such a rare medical condition, confirmation of a new PML case related to Tysabri would likely make it more difficult for Elan and Biogen to convince the FDA of the Tysabri’s safety.

Coincidentally, on May 26, 2005, at the company’s annual meeting in Dublin, Ireland, Elan Chief Executive Kelly Martin had predicted that Tysabri would return to the market.  In elaboration, Mr. Martin said their internal safety profile investigation regarding Tysabri was moving forward such that the probe would conclude by mid-to-late summer 2005.  Mr. Martin confidently stated that officials from both companies would meet with the FDA to discuss the "path forward for Tysabri" once their internal review was concluded.  "It’s a question of when and what path that takes, not a question of if," Tysabri is returned to the U.S. market, Mr. Martin told Elan investors at the May 2005 Dublin meeting.

(Posted by: Tom Lamb)