Pfizer Inc reported disappointing quarterly revenue on declining demand for its prescription medicines, exposing the risks the world's biggest drugmaker would face if it sells better-performing units like its nutritional products business. Ian Read, the company's new chief executive officer, told analysts on a conference call that although Pfizer will provide rough outlines by year's end on which units might be sold or spun off, it will take longer to develop full-fledged plans. There will be no "Big Bang" this year, he said.