Rhythm Pharmaceuticals Announces Preliminary Results From Ongoing Phase 2 Trial Evaluating RM-718 In Patients With Acquired Hypothalamic Obesity; BMI Reductions Consistent With Setmelanotide And Bivamelagon; Sees -11.6% Mean Reduction In BMI From Baseline At Week

Eleven patients with acquired HO were enrolled in the ongoing, open-label trial. Key preliminary findings include:

• -11.6% reduction in mean BMI from baseline (n=7) after 16 weeks of RM-718;
• RM-718 efficacy results at 16 weeks comparable to mean BMI reduction of -10.1% with bivamelagon (600 mg dose; n=7) at 14 weeks and -10.1% BMI reduction with setmelanotide at 16 weeks (n=64 patients in Phase 2 and 3 trials); and
• Two (2) mild instances of hyperpigmentation were reported and were limited to the injection site, with no generalized hyperpigmentation observed.

RM-718 was generally well tolerated, with the most common adverse events being injection site reactions, nausea, and vomiting.

Eight (8) patients remained on active treatment as of July 16, 2026, including two (2) patients who had not yet reached 16 weeks on therapy. Two participants discontinued treatment due to adverse events: injection site induration and nausea. One patient withdrew from the extension portion of the trial.

"These encouraging results suggest that RM-718 has the potential to deliver clinically meaningful BMI reductions in patients with acquired HO," said David Meeker, M.D., Chair, President and Chief Executive Officer of Rhythm Pharmaceuticals. "The magnitude of BMI reduction observed to date is consistent with what we have seen with both setmelanotide and bivamelagon at similar treatment durations. Importantly, we have observed very limited hyperpigmentation, with two mild cases reported isolated to the injection site. We look forward to continuing to advance RM-718 as a potential next-generation treatment option for patients living with rare MC4R pathway diseases."