Xconomy -- Concert Pharmaceuticals climbed the charts of the Boston area’s hottest biotechs last year when it revealed an incentive-laden deal with the drug giant GlaxoSmithKline potentially worth more than $1 billion. Roger Tung, the CEO of Concert, met with me last week at the biotech startup’s Lexington, MA, headquarters and talked about the work his firm is doing to earn as much of that $1 billion from London-based Glaxo (NYSE:GSK) as it can.