West Coast Editor

The approved lymphoma drug Rituxan (rituximab) hit its primary endpoint in a Phase III trial against rheumatoid arthritis, but company officials are still analyzing the data, noted Sunil Agarwal, Genentech Inc.'s medical director, and "with respect to safety data, we realize these results are preliminary."

Wall Street proved lukewarm on the news, pushing Biogen Idec's stock (NASDAQ:BIIB) up 63 cents, to close at $35.40. Shares of South San Francisco-based partner Genentech Inc. (NYSE:DNA) closed at $58.37, up $1.22.

Still, the Phase III news was good in a patient population recognized as challenging - those who have not responded well or proved intolerant to anti-tumor necrosis factor drugs, typically used in later stages of the disease, Agarwal noted.

The primary endpoint of the 520-patient study called REFLEX (Randomized Evaluation of Long-term Efficacy of Rituximab in RA) was a greater proportion of Rituxan-treated patients achieving an American College of Rheumatology 20 response at week 24, compared to placebo.

ACR 20 means a 20 percent improvement in the number of swollen and tender joints, as well as a 20 percent improvement compared with baseline in three of five disease-activity measures: patient assessment, physician assessment, pain scale, a Health Assessment Questionnaire and the value for one acute-phase reactant (erythrocyte sedimentation rate or C-reactive protein).

Participants were randomized to get either Rituxan (1,000 mg intravenously on days 1 and 15) or placebo. All patients received a stable dose of methotrexate and a two-week course of corticosteroids, as well.

"It's the first Phase III study to show benefit in this patient group," Agarwal said. Next come talks with the FDA that will determine how to proceed, but how soon a decision will be made is unclear.

"I can't give you an exact date," he said.

The Phase III trial follows positive preliminary results reported in November from a Phase IIb study that evaluated the efficacy and safety of Rituxan in moderate to severe RA patients who failed prior treatment with at least one disease-modifying anti-rheumatic drug.

Researchers' early look at the Phase III data revealed no unexpected safety signals, and the most common side effects in the Rituxan arm included headache, upper respiratory tract infection and nasopharyngitis. Serious adverse events proved comparable across both treatment arms.

Approved in 1997 for non-Hodgkin's lymphoma, Rituxan is being developed in a three-way deal involving Genentech; Cambridge, Mass.-based Biogen Idec Inc.; and F. Hoffmann-La Roche Ltd., of Basel, Switzerland.

Analyst Jennifer Chao, with Deutsche Bank Securities Inc. in New York, in a research note on Biogen Idec, maintained a "sell" rating. She viewed the early Phase III data as "provocative" but said fuller efficacy data - such as ACR 50 and ACR 70 scores - would better help characterize Rituxan's feasibility in RA.