Are we ready for the Great Obesity Drug Gold Rush of the 2020s?For high-profile biotech Viking Therapeutics (VKTX -13.36%), Monday was very much a good news/bad news kind of day. The company reported quite encouraging clinical results from a version of its investigational weight-loss drug. Before long, however, this was overshadowed by promising news from rival developers of similar treatments.Ultimately, after an early surge, Viking's shares closed the day more than 13% lower in price.Weight loss for profi ...