Aetna Inc. has hired Dr. Troyen Brennan to be chief medical officer.

Brennan has been a professor of medicine at Harvard University since 1995, and he has been president of Brigham and Women’s Physicians Organization, Boston, a provider group affiliated with the prestigious Brigham and Women’s Physician Hospital Organization.

Brennan has been a professor of law and public health at Harvard’s public health school since 1992.

Brennan has a master’s degree from Oxford University, where he was a Rhodes Scholar. He also has a medical degree from Yale University, a master’s degree in public health from Yale, and a law degree from Yale.

In other personnel news:

- CIGNA HealthCare, Bloomfield, Conn., a unit of CIGNA Corp., Philadelphia, has named Christopher De Rosa president and general manager of the CIGNA HealthCare business in Southern California.

De Rose previously was a senior vice president in CIGNA’s government and Taft-Hartley plan business.

DeRosa has a bachelor’s degree from the University of California at Los Angeles and a master’s degree in business from the University of California at Irvine.

- Independence Blue Cross, Philadelphia, has promoted William Haggett to chief marketing officer.

Haggett has been the president of an Independence Blue subsidiary, AmeriHealth New Jersey. He succeeds Christopher Butler, who became Independence Blue’s chief operating officer in 2003.

Haggett has a bachelor’s degree in psychology from Southern Connecticut State University, a master’s degree in research methods and statistics from Southern Connecticut, and a doctorate in public and urban education policy from Temple University.