Calpers' social, corporate activism drawing attention in bear market as some fear its aggressive tactics may cost governments, firms money -...When the AIDS Healthcare Foundation wanted drug maker GlaxoSmithKline PLC to lower the $438 a person it charges in developing countries for a year's worth of AZT, it turned to an unlikely ally: America's largest pension fund...In its letter to Glaxo...Calpers praised the drug maker for ''established and effective humanitarian programs.'' But Calpers pressed Glaxo to ''immediately and continually evaluate the company's humanitarian efforts in light of a changing environment, including its response to the AIDS epidemic.'' Calpers wants Glaxo's findings to be scrutinized by an independent body like Doctors Without Borders.