Novo Nordisk and Eli Lilly reign over the anti-obesity drug market, and don't expect this duopoly to end soon, analysts say. But other companies — both big and small — are hoping to grab a piece of this lucrative market. In a research note, Piper Sandler analyst Yasmeen Rahimi said the firm is tracking more than 150 studies with 78 agents in development. Some are expected to…