Bringing a new drug to patients requires 10-15 years, billions of dollars, and navigating complex biology, manufacturing, and regulatory hurdles—here's how bimagrumab went from myostatin research to potential obesity therapy. Dr. Lloyd Klickstein pulls back the curtain on modern drug development, walking through target discovery, antibody engineering, animal testing, clinical trials, and the strategic decisions that determine which medicines reach patients. Using bimagrumab as a case study, he explains how scientists identify unmet medical needs, why most programs fail early, and how unexpected findings—like fat loss and improved metabolic markers—can reshape a drug's entire development path. Bimagrumab increases muscle mass 4-8% in humans but delivers 23% body weight loss and 46% fat loss when combined with semaglutide—comparable to bariatric surgery outcomes.