Rituxan Joins List of Treatments

By KEITH J. WINSTEIN

April 15, 2008; Page B9

Rituxan, a top-selling drug from Genentech Inc. and Biogen Idec Inc., failed to slow the course of the most severe form of multiple sclerosis in a large study, the companies said.

The findings make Rituxan at least the sixth unsuccessful attempt to treat so-called primary-progressive MS, or PPMS. In the U.S., about 35,000 to 40,000 people have primary-progressive MS, out of roughly 350,000 to 400,000 total MS patients.

There are no approved treatments for PPMS. Genentech and Biogen had hoped that Rituxan -- which is approved for blood cancer and rheumatoid arthritis -- might become the first such treatment. The drug costs about $20,820 a year at the dosage used.

But in the companies' study, which followed 439 patients for 96 weeks, Rituxan didn't significantly slow the course of the disease, which gradually robs patients of motor function and causes tremors, tingling and fatigue. Secondary results -- like whether Rituxan improved MRI scans of patients' brains -- weren't released.

"We are disappointed in the outcome of the primary endpoint, but not surprised given the significant clinical challenges presented by PPMS," said Hal Barron, chief medical officer at Genentech, in a statement.

A successful result could have yielded $236 million to $359 million in annual sales to the two companies, according to a Bear Stearns estimate. Genentech gets 60% of the profits from Rituxan, with 40% going to Biogen. Total sales were $2.3 billion last year.

In a smaller study last year, Rituxan slowed down the less-severe form of MS, which has several approved drugs, including Biogen's Avonex and Tysabri. The companies have disagreed over what to do next. The matter is subject to an arbitration hearing this summer.

Rituxan is being studied in lupus, another immune-system disease with few treatment options. Genentech has said results may be released within a few weeks.

Write to Keith J. Winstein at keith.winstein@wsj.com