The first combination of breakthrough drugs that boost the immune system to fight cancer has been approved, giving maker Bristol-Myers Squibb an early lead over competitors testing their own combos in a pharmaceutical gold rush of sorts. The Food and Drug Administration has given accelerated approval to a regimen combining the New York-based drugmaker's two immuno-oncology drugs, Opdivo and Yervoy, to treat patients with advanced melanoma who have a particular genetic variation.