Rhythm’s HO Launch Accelerates with 400+ Start Forms, While RM-718 Data Derisks the Next-Gen MC4R Franchise

A first full quarter of IMCIVREE in acquired hypothalamic obesity delivers broad prescriber activation and 19% sequential revenue growth; RM-718 shows comparable efficacy without hyperpigmentation.

RYTM · Earnings Call · 2026-08-04

Launch Momentum: HO Start Forms and Prescriber Breadth

The second quarter was the first full period of IMCIVREE's U.S. launch in acquired hypothalamic obesity (HO), and the metrics suggest a meaningful read-through for the company's long-term growth. start forms reached more than 400 in the 14 weeks from FDA approval on March 19 to June 30, including 66 from converted trial patients. As “we have seen strong demand, broad and expanding prescriber engagement and activation and positive early payer experience supporting access,” — Jennifer Chien, Commercial or Sales Executive · 2026-08-04 the launch is tracking ahead of the company's prior BBS experience. The breadth is notable—nearly 300 unique prescribers, with adult and pediatric endocrinologists accounting for 43% and 37% respectively, and about 20% having prescribed to more than one patient. This builds on earlier groundwork. In the Q1 2026 call, Jennifer Chien noted that the field team had been targeting a growing list of potential patients, saying “the 2,000 number has continued to increase even since that September date.” — Jennifer Chien, Commercial Leader / Sales Leader · 2026-05-05 The current quarter's data suggest that the conversion from education to prescription is now materializing. The company has also moved to split its commercial teams—42 territory managers focused exclusively on HO and a dedicated BBS group—to maximize both opportunities.

We've been working on HO for a number of years and now to be at a point where we're actually getting the drug to patients, and we're seeing a community that's embracing it and responding well to their initial experience is, like I said, it's very exciting for us.
David Meeker, CEO · 2026-08-04

RM-718: Derisking the Next-Gen Franchise

The pipeline update was equally significant. RM-718, a weekly MC4R agonist, posted a mean BMI reduction of 11.6% at week 16 in a 7-patient cohort with acquired HO—comparable to setmelanotide (10.1%) and bivamelagon (10.1%). Crucially, the safety profile showed no generalized hyperpigmentation. As CEO David Meeker summarized, “RM-718 was generally well tolerated with the most common adverse events being injection site reactions and nausea.” — David Meeker, CEO · 2026-08-04 This generalized hyperpigmentation advantage, combined with a weekly dosing schedule, positions 718 and bivamelagon to extend the franchise well beyond the current setmelanotide patent life. The company is now enrolling Part D in Prader-Willi (PWS) with completion expected by year-end, and plans a pivotal bivamelagon trial in HO at year-end.

Financial Trajectory and Guidance

On the financial side, global net product sales reached $71.3 million, up 19% sequentially, with U.S. revenue contributing 72% of the total. The Total Revenue line reflects this momentum, though the company remains deeply unprofitable. R&D expenses rose modestly, while SG&A increased 6% sequentially to support commercial expansion. The company updated 2026 non-GAAP OpEx guidance to $363M–$397M, with R&D trimmed by $20M on CMC timing shifts. Cash stood at $331M, sufficient for at least 24 months. Management was careful not to extrapolate too quickly, but the early signal is positive. As Jennifer Chien noted in the prior quarter about launch dynamics, “the vast majority of the patients or the physicians are waiting to have those conversations with their patients as they come in for their regularly scheduled visits,” — Jennifer Chien, Commercial Leader / Sales Leader · 2026-05-05 yet the current quarter's pace suggests that those conversations are converting to prescriptions faster than anticipated.

International Expansion and the PWS Catalyst

Beyond the U.S., Yann Mazabraud detailed progress in Japan and Europe. Japan approval and launch are expected by year-end 2026, with a prevalence of 5,000–8,000 patients—a higher per-capita rate than the U.S. or Europe. The EU marketing authorization was granted in May, with launches in major countries expected in 2027. Meanwhile, the PWS data from the setmelanotide open-label study, presented at ENDO, showed clinically meaningful BMI and hyperphagia improvements, setting the stage for a pivotal decision. The stock has responded well—up 30% over the past 90 days—though it remains about 6% below its December peak. With a acquired HO launch gaining traction, a derisked next-gen pipeline, and a clear path to global expansion, Rhythm is transitioning from a single-indication story to a multi-asset, multi-market rare-disease platform. As David Meeker said, “there may have been a little bit of pent-up urgency, there was no bolus in this thing. We feel really good about all these metrics and how they speak to the future.” — David Meeker, CEO · 2026-08-04