WASHINGTON (AP) - Pfizer said Tuesday it is asking U.S. regulators to authorize its experimental pill for COVID-19, setting the stage for a likely launch of the promising therapy in the coming weeks.The company's filing comes as new infections are rising once again, driven mainly by hot spots in states where colder weather is driving more Americans indoors.It is one of a handful of pills that have recently been shown to significantly cut hospitalizations and deaths among people infected with COVID-19.