Among the earnings stories for Wednesday, Oct. 21, from AP Financial News: NEW YORK (AP) ¿ Biotechnology company Amgen Inc. said lower costs in its research and sales units pushed up third-quarter profit 24 percent, despite a continued downturn in anemia drug sales. LAKE FOREST, Ill. (AP) ¿ Pactiv Corp., which makes Hefty garbage bags and packaging materials, said that its third-quarter profit rose 64 percent to $87 million even as sales declined 9 percent. BRENTWOOD, Tenn. (AP) ¿ Retailer Tractor Supply Co. said its third-quarter profit rose 39 percent as sales increased slightly and it improved its gross margin. MENLO PARK, Calif. (AP) ¿ Robert Half International Inc. said its third-quarter profit fell 86 percent, though the staffing services company still beat Wall Street estimates. PHOENIX (AP) ¿ Knight Transportation Inc. said its third-quarter profit fell 18 percent as weak consumer spending continues to hurt freight markets, and the trucking firm warned that demand isn't picking up fast enough to support price increases.