* Athena Neurosciences Inc., of South San Francisco, consummated the sale of $325 million worth of 4.75 percent exchangeable notes due Nov. 15, 2004. Athena did the financing on behalf of its parent company, Elan Corp. plc, of Dublin, Ireland, to fund product and corporate acquisitions, among other things. The notes are exchangeable for Elan American Depositary Shares at a rate of 14.0758 shares per $1,000 of principal invested.

* Medarex Inc., of Annandale, N.J., and Centeon LLC (a joint venture of Frankfurt, Germany-based Hoechst AG and Rhone-Poulenc Rorer Inc., of Collegeville, Pa.) said Medarex achieved its first milestone in their collaboration. The companies are developing MDX-33, a humanized antibody for the treatment of autoimmune hematological disorders. A Phase Ia clinical trial showed the product was well tolerated at a dose that may be capable of shutting off an autoimmune function involved in diseases such as idiopathic thrombocytopenia purpura (ITP), a platelet disorder that can cause uncontrolled bleeding.

* Mycogen Corp., of San Diego, approved a private placement of up to $75 million in newly issued shares of Mycogen stock with the company's majority owner, DowElanco, a wholly owned subsidiary of The Dow Chemical Co., of Midland, Mich. The share price in one transaction or a series of transactions will be, for each transaction, the average of the daily closing prices of the company's stock on the Nasdaq market for all trading days within the 90 calendar days immediately before the transaction. As of Oct. 31, DowElanco owned 18.1 million shares, or about 57.5 percent of Mycogen's 31.4 million outstanding shares.

* NeoRx Corp., of Seattle, said it will begin Phase II trials in the second quarter of next year for Biostent, its product to inhibit restenosis following balloon angioplasty. Data from a Phase I trial showed the drug, safe at all levels, may reduce deaths and clinical events such as myocardial infarction and revascularization procedures.

* Urogenesis Inc., of Santa Monica, Calif., raised $8 million in an initial round of financing, which was managed by the company and involved private placements. The start-up company is focused on treatments for prostate cancer. It will work to develop new ways to diagnose and treat the disease by identifying protein markers or genes that can be used to detect early-stage disease and distinguish between hormone-dependent and hormone-independent tumors.

* VIMRX Pharmaceuticals Inc., of Wilmington, Del., presented preclinical data on an anticoagulant at the scientific meeting of the American Heart Association, in Orlando. The compound, VM201 (Factor IXai), selectively prevented blood clots that can lead to stroke during cardiac surgery, while reducing unwanted bleeding complications. VM 201 inhibits Factor IXa.