The stock surged 12.9% following a quarter that demonstrated clear initial traction with the newly approved acquired hypothalamic obesity (HO) indication, a significantly larger market opportunity than Bardet-Biedl syndrome (BBS). Early launch metrics and payer receptivity for HO drove optimism about Rhythm’s commercial expansion and long-term growth potential.

• Q1 revenues reached $60 million, reflecting steady growth in the base BBS business despite it being an ultra-rare disease.
• The acquired HO launch is off to a solid start with over 150 patient start forms submitted since the March approval, indicating strong physician and payer engagement.
• Commercial infrastructure expanded substantially, with sales reps increasing from 16 (BBS) to 42 (HO), signaling Rhythm’s commitment to capturing the larger HO patient population (~10,000 estimated in U.S. and Europe).
• Positive early data from Japan and anticipated regulatory approval before year-end reinforce the global growth thesis for HO.
• Upcoming clinical data presentations and planned Phase III trial initiation aim to sustain momentum and expand the therapeutic portfolio in HO and Prader-Willi syndrome.