* Affymetrix Inc., of Santa Clara, Calif., named Sue Siegel to the newly created position of senior vice president, marketing and sales.
* Aksys Ltd., of Lincolnshire, Ill. named John LaLonde vice president of research and development.
* Alexion Pharmaceuticals Inc., of New Haven, Conn., named Louis Matis senior vice president and chief scientific officer, Stephen Squinto senior vice president and chief technology officer, and Bernadette Alford senior vice president of product development.
* Alpha Therapeutic Corp., of Los Angeles, Calif., appointed Michael Dubinsky director for regulatory compliance.
* Ambi Inc., of Tarrytown, N.Y., named Lawrence Chakrin vice president, product development; Gerald Shapiro vice president, finance and administration, and chief financial officer; and Alan Gallantar treasurer and controller. In addition, Benjamin Sporn was promoted to senior vice president, general counsel and secretary; Jon de la Harpe was promoted to vice president, technical operations; and Victor Moreno to vice president and president, Nutrition 21.
* Amylin Pharmaceuticals Inc., of San Diego, Calif., named Joseph Cook Jr., chairman of the board and CEO.
* Anika Therapeutics Inc., of Woburn, Mass., named Charles Sherwood vice president of process development.
* Antisoma plc, of London, U.K., named the following to its board of directors: Glyn Edwards, director of business development at Therapeutic Antibodies Inc.; Barry Price, primary production director of Glaxo Wellcome Group of Middlesex, U.K.; and Francois Legault, executive vice president, investment and subsidiaries for BioChem Pharma Inc. of Laval, Canada.