Soleno Therapeutics reported preliminary second quarter sales of $31 to $33 million for its Prader-Willi syndrome drug Vykat XR, surpassing analyst expectations despite a high annual price point. Concurrently, Rhythm Pharmaceuticals achieved statistically significant BMI reductions with its oral melanocortin-4 receptor agonist bivamelagon in Phase 2 trials for acquired hypothalamic obesity, planning Phase 3 discussions. These developments highlight momentum in rare disease therapeutics targeting unmet metabolic and genetic disorders.