William C. Steere Jr., longtime board member for Pfizer Inc. and chief executive of the firm during its heyday in the 1990s, will be leaving his position as one of the company's directors in a move that some see as reaffirmation of a major shakeup playing out at the pharmaceutical giant.

The 74-year-old Steere's retirement from the board, announced unceremoniously in a footnote to a proxy filed by Pfizer earlier this week, will take effect next month after the company's annual meeting. Another director, Robert N. Burt, former chairman and chief executive of chemicals manufacturer FMC Corp. and machinery manufacturer FMC Technologies Inc., will be retiring at the same time.

But it was Steere's retirement that caught the eye of many industry watchers, including Ed Silverman, who writes the influential Pharmalot blog and broke the story. Steere served as Pfizer chief executive from 1991 to 2000, and as chairman from 1992 to 2001, during a time when Pfizer brought to market such leading medications as Viagra, Zoloft and Zithromax.

"His departure signals the end of an era, given the domineering role he sometimes played, notably a push for outsized acquisitions," Silverman said.

Steere, initially an opponent of major acquisitions, eventually became an adherent of the strategy, turning Pfizer into a virtual company-eating machine, including megamergers with Warner-Lambert, Pharmacia and Wyeth Pharmaceuticals. Pfizer has major research facilities in Groton and New London.

The Warner-Lambert deal brought Pfizer the world's leading medication, cholesterol drug Lipitor, but subsequent acquisitions weren't as successful. The Wyeth merger, according to Silverman, led to a rift between Steere and former chief executive Jeffrey B. Kindler, who had preferred a diversification strategy, and may have resulted in Kindler's ouster at the end of last year.

Pfizer's current chief executive, Ian Read, said to be a Steere loyalist, nevertheless has begun reconsidering some of the chairman emeritus' strategies. In the past month, Read has signaled his intention to seriously look into selling off parts of the company, including animal health and consumer product divisions that largely are the legacy of the Wyeth acquisition.

"At least symbolically, Steere's departure could mean that Ian Read ... has a free hand," according to Matthew Herper in his blog The Medicine Show.

On the other hand, according to Silverman, Pfizer's new chairman of the board, 70-year-old George Lorch, is considered a Steere protege and they regularly play golf together.

"Steere will continue to cast a shadow over the Pfizer board," Silverman said.

l.howard@theday.com