Shares in biopharmaceutical company Viking Therapeutics (VKTX 5.35%) were up by 6.3% at 12:30 a.m. ET today. The move likely stems from the market digesting the previous day's news that Viking had initiated a phase 3 trial of its most promising program in its pipeline, namely VK2375, a treatment for metabolic disorders, including obesity.Why VK2375 is exciting investorsThere are probably two key reasons why the market likes the initiation of a phase 3 trial:VK2375 is a dual GLP-1/GIP receptor agonist simila ...