It was activism that drew the world's attention to the HIV epidemic and to the need for ethical standards in AIDS-drug testing. And activism is once again playing a role, this time in challenging a drug company, Merck, over the price of HIV/AIDS medicine Isentress. The AIDS Healthcare Foundation (AHF), which operates free HIV/AIDS clinics in the US and abroad, this week banned Merck drug reps from calling on staff in its facilities.