Updated from 6:20 p.m. EDTHank McKinnell, the Pfizer ( PFE) chief executive who has irked investors by failing to lift the drugmaker's share price in five and a half years at the helm, will be ceding the top corporate post and retiring sooner than planned. The world's biggest pharmaceutical maker said Friday that Vice Chairman Jeffrey Kindler will take the CEO post from McKinnell, who will remain chairman until February. Kindler, a 51-year-old who also serves as Pfizer's general counsel, joined the company in 2002 from McDonald's ( MCD). "The board and I see the pharmaceutical industry changing rapidly," McKinnell said in a statement. "Pfizer is changing as well and aggressively transforming its business model to build the next-generation Pfizer. With these initiatives well underway, it is time to transition to new leadership to accelerate the company's transformation." McKinnell became CEO in January 2001. Pfizer's stock closed the first trading day of that year at $41.19, and Friday it ended at $26.11, a decline of roughly 37%. However, the shares are up 14% from where they finished 2005. "Hank McKinnell has led Pfizer through some of its more challenging times," Lead Director Stanley Ikenberry said in a press release. "He was instrumental in taking the company from 14th to first in the global pharmaceutical industry, integrating both Warner-Lambert and Pharmacia into Pfizer and bringing a wide range of new medicines to market." Previously, McKinnell had intended to retire early in 2008. Karen Katen, a vice chairman and the president of Pfizer's human health group, and David Shedlarz, another vice chairman, were seen as the other two possible replacements for McKinnell. Katen joined Pfizer in 1974, and Shedlarz went to the New York-based drugmaker in 1976. McKinnell has been with Pfizer for 35 years, and he said now is the time "to pursue other business and philanthropic interests."