Biotech Values

[DewDiligence]

Re: Biogen Halts Enrollment in Tysabri Trial, Citing Slow Pace

[Gilenya was surely responsible, at least in part, for this trial’s inability to achieve the planned enrollment. BIIB is unlikely to acknowledge this, of course.]

›03/15/2011 2:53PM
Dow Jones Newswires

Biogen Idec Inc. (BIIB) has halted enrollment in a large, long-term clinical trial aimed at testing the earlier use of multiple sclerosis drug Tysabri, citing a slower-than-expected pace of finding participants.

The Surpass study aims to test the effectiveness of Tysabri, sold with Elan Corp. (ELN), when patients switched from more widely used drugs. Tysabri has proved to be highly effective; however, because of a link to a rare brain infection, the patients taking the drug tend to be those who have stopped responding to other drugs or have aggressive cases of MS.

The study started a year ago and had aimed to enroll 1,800 patients to be followed for about two years, yielding data in 2013 or 2014. Enrollment was stopped last month, but participating patients will continue in the trial.

Biogen spokeswoman Kate Weiss declined to comment on the number of patients enrolled, citing policy. The company has decided to devote its resources toward "risk stratification" efforts for the drug and remains dedicated to studying its effectiveness, she said.

Tysabri has been linked in a small number of patients to a serious brain infection called progressive multifocal leukoencephalopathy, or PML. Global sales rose 16% to $1.2 billion last year, although growth has been lower than originally expected in recent years because of the risks of the infection.

Biogen is developing a blood test that may better determine the chances of patients contracting PML. The test recently received CE Mark approval in Europe and the companies are conducting large studies of its effectiveness.

The Surpass trial was designed to measure Tysabri's effectiveness in patients with active MS that have switched from either Teva Pharmaceutical Industries Ltd.'s (TEVA) Copaxone or Rebif, sold by Pfizer Inc. (PFE) and Germany's Merck KGaA (MKGAY).

The goal of the Surpass trial is to get physicians to use Tysabri when patients aren't responding to their current therapy, rather than switching them to more mainstream therapies and using Tysabri as a last resort.

But the design of the trial meant that patients weren't assured that they would switch treatments at all, something that proved to be a hurdle, Weiss said.

The difficulty comes as many new MS treatments are in development, and Novartis AG (NVS) recently launched Gilenya, the first oral treatment for the condition.

"The MS environment is changing and we need to adapt to that change," Weiss said. "This made it challenging to enroll in light of the current clinical trial landscape and the trial itself."‹