By Carolyn Pritchard, CBS MarketWatch.com
SAN FRANCISCO (CBS.MW) -- Genentech said late Monday the U.S. Attorney's office is investigating the promotion of its key oncology drug, Rituxan.
Genentech said in a statement it has received a subpoena from the U.S. Attorney's Office of Eastern Pennsylvania for documents related to the promotion of the drug, used in the treatment of non-Hodgkin's lymphoma.
The investigation is both civil and criminal in nature, the South San Francisco-based biotech firm said. Genentech /zigman2/quotes/226092395/composite DNA +2.41% said it plans to cooperate.
Rituxan helped drive Genentech to report revenues of more than $1 billion for the second quarter of this year.
The drug accounted for about 40 percent of its second-quarter revenue of $1.06 billion. Rituxan brought in $424.7 million in for the period, slightly below Wall Street analyst expectations for about $427 million in sales.
Genentech is scheduled to release third-quarter results after Wednesday's closing bell.
The drug is marketed by Genentech and Biogen Idec /zigman2/quotes/201531540/composite BIIB -1.43% in the U.S.
Swiss drug giant Roche /zigman2/quotes/206948568/delayed RHHVF +0.94% markets Rituxan in all other nations where it is sold, except Japan.
The three companies are also are testing Rituxan for rheumatoid arthritis in combination with the drug methotrexate.
Phase II clinical trial results were published in the New England Journal of Medicine back in June that showed the combination was effective in treating moderate-to-severe cases.
Shares of Genentech rose 83 cents, or 1.6 percent, to end Monday's session at $53.99.