Genentech

(DNA)

and

Biogen Idec

(BIIB) - Get Report

said a clinical study of their drug Rituxan improved symptoms in patients with moderate-to-severe rheumatoid arthritis.

The companies also said a preliminary analysis of the phase II clinical data did not reveal any unexpected safety signals. Testing involved a total of 465 patients from the United States, Canada, Europe and Australia.

Rituxan received initial FDA approval in November 1997 for the treatment of non-Hodgkin's lymphoma and is now being tested to treat other diseases.

In early October, Genentech disclosed that the U.S. attorney in eastern Pennsylvania had subpoenaed documents about Rituxan. The company said the "inquiry is both civil and criminal in nature," adding that the subpoena is related to the promotion of the drug..

Rituxan recorded revenue of $1.49 billion last year.

Genentech and Biogen Idec sell the drug through a joint venture in the U.S. Roche of Switzerland had worldwide rights, except Japan.

Biogen shares added 71 cents, or 1.2%, to $58.36 in premarket trading. Genentech shares closed at $46 Monday.