* Cell Pathways Inc., of Horsham, Pa., named Brian Hayden vice president of finance and administration and chief financial officer; Robert Stevenson, intellectual property counsel; and Robert Towarnicki, who is CEO, president.

* Cell Therapeutics Inc., of Seattle, named Carolyn Paradise head of medical affairs.

* Celtrix Pharmaceuticals Inc., of Santa Clara, Calif., appointed to its board of directors Barry Sherman, president and CEO of Anergen Inc., of Redwood City, Calif.

* Cephalon Inc., of West Chester, Pa., named Jeffry Vaught president of research and development; Peter Grebow, senior vice president of worldwide business development; and Efraim Shek, vice president of drug development.