Irish drug maker Elan Corp. Plc (ELN) said Tuesday it received a subpoena from the U.S. Securities and Exchange Commission seeking information related to disclosures last year about Elan's multiple-sclerosis drug Tysabri and an experimental Alzheimer's disease drug.

Elan disclosed in a regulatory filing it received the subpoena Sept. 24 from the SEC's New York office, and it intended to provide the SEC with materials in connection with the commission's investigation into Elan.

The exact nature of the SEC's investigation wasn't immediately known, and a commission spokesman declined comment. An Elan spokeswoman couldn't immediately be reached.

The subpoenas concern two separate announcements related to Elan last year. On July 31, 2008, Elan and its marketing partner, Biogen Idec Inc. (BIIB) notified regulatory agencies of two confirmed cases of a rare brain infection called progressive multifocal leukoencephalopathy, or PML, in multiple-sclerosis patients treated with Tysabri. Tysabri had previously been withdrawn from the market due to PML risk, then relaunched, and the companies have monitored the side effect closely.

Separately, two days earlier, researchers presented the results of a mid-stage patient trial of bapineuzumab, an Alzheimer's drug Elan co-developed with Wyeth (WYE), at a medical-meeting in Chicago. Wyeth and Elan said the data supported their prior decision to move the drug into late-stage trials, which are still underway.

The full data presentation for bapineuzumab disappointed many investors, who felt it was less impressive than the preliminary findings Wyeth and Elan had included in a June 2008 press release.

Elan's American depositary receipts were quite volatile during this period, including a plunge of more than 70% over three days in late July and early August 2008.

Johnson & Johnson (JNJ) recently acquired Elan's rights in the Alzheimer's disease partnership with Wyeth.

Spokespeople for J&J and Biogen declined to comment. A Wyeth spokesman couldn't immediately be reached.

-By Peter Loftus, Dow Jones Newswires; 215-656-8289; peter.loftus@dowjones.com