[April 15, 2008]

Genentech, Biogen Idec's Rituxan Misses Lofty Mark in MS Trial

(BioWorld Today Via Thomson Dialog NewsEdge) Investors are looking ahead to what they expect will be more promising data for Rituxan in lupus, after Genentech Inc. and Biogen Idec Inc. announced disappointing - but not surprising - study results for Rituxan in multiple sclerosis.

The two companies, which co-market Rituxan in the U.S., said a Phase II/III study of Rituxan failed to show that the drug slowed disease progression in patients with a hard-to-treat form of MS known as primary-progressive multiple sclerosis, or PPMS.

In addition, the study showed that serious adverse events were higher in the Rituxan-treated group (16.4 percent) compared to those given placebo (13.6 percent). The incidence of serious infections was 4.5 percent with Rituxan compared to less than 1 percent with placebo.

Detailed safety data from the PPMS study currently are being evaluated, and Genentech and Biogen Idec plan to submit the study data for presentation at an upcoming medical meeting.

Currently, there is no FDA-approved therapy for PPMS, which affects about 10 percent of MS patients. PPMS is recognized as one of four disease states of MS, and has no distinct periods of relapse or remissions.

PPMS was seen as a tough indication to obtain for Rituxan, though the companies said there was evidence of the drug's activity in MS. "We are disappointed in the outcome of the primary endpoint, but not surprised given the significant clinical challenges presented by PPMS," said Hal Barron, Genentech senior vice president of development and chief medical officer. But in a statement from the company he added, "There was some evidence of biologic activity, and we will continue to review all the data to better understand the role of B cells in MS."

Analysts expressed more confidence in lupus as a potential new indication for Rituxan.

Joel Sendek, an analyst with Lazard Capital Markets, said in a research note that "PPMS was a high hurdle for Rituxan as it is a difficult to treat indication where many compounds have failed." He estimated that "the foregone market opportunity" was about $300 million.

Sendek, echoing the sentiments of other analysts, expects lupus to have a higher likelihood of success than the MS indication for Rituxan.

Rituxan is being studied in other autoimmune diseases for significant unmet medical needs, including systemic lupus erythematosus (SLE), lupus nephritis and antineutrophil cytoplasmic antibodies-associated vasculitis. Data from a study of Rituxan in SLE are expected to be released soon, and data for Rituxan in lupus nephritis are due in early 2009.

Credit Suisse analyst Michael Aberman said in a research note that systemic lupus and lupus nephritis are "larger market opportunities that have the chance to move the needle for Biogen."

It is widely assumed that Rituxan would be used as an induction therapy in lupus, followed by belimumab as a maintenance therapy, Leerink Swann analyst Joseph Schwartz said in a research note. In that sense, Human Genome Sciences Inc. (HGSI) and GlaxoSmithKline Plc's belimumab (Lymphostat-B) stands to benefit from the negative Rituxan study in MS, he said.

"The door may now be left open for belimumab to dominate both induction and maintenance in multiple autoimmune diseases," Schwartz wrote. He added that belimumab, a monoclonal antibody, "is safer than Rituxan since it merely down-regulates B-cell survival factors, but does not permanently wipe out b-cells that are required to prevent infections."

Phase III studies of HGSI's BLYSS-52 and -76 are ongoing, and data are expected to be reported in 2009, Schwartz said.

Estimates for the potential market for lupus are as high as $1.9 billion, but could be smaller for Rituxan - around $800 million - if use is restricted to the most severe cases and if there is no other market competition, Bear Stearns analyst Mark Schoenebaum said in a research note. Bristol-Myers Squibb Co.'s Orencia also is being evaluated for lupus, along with HGSI's compound, he said.

In separate news, Cambridge, Mass.-based Biogen Idec said it plans to provide an update on its pipeline and multiple sclerosis and neurology products at the American Academy of Neurology annual meeting, which wraps up Saturday. Besides Rituxan, Biogen's other approved products are Avonex, the most prescribed treatment for relapsing forms of MS worldwide, and Tysabri, approved for relapsing forms of MS in the U.S. and relapsing-remitting MS in the European Union.

Shares in Biogen Idec (NASDAQ:BIIB) rose $1.21 Tuesday, closing at $64.93.

Shares in South San Francisco-based Genentech (NYSE:DNA) fell 63 cents, closing at $74.06. n

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