Rhythm Pharma Eyes Blockbuster Market with Key FDA Date Approaching

BOSTON, MA – February 26, 2026 – Rhythm Pharmaceuticals (Nasdaq: RYTM) capped a year of robust commercial growth with strong fourth-quarter financial results, driven by surging global sales of its rare obesity drug, IMCIVREE® (setmelanotide). However, the impressive revenue figures were overshadowed by the company's focus on a series of transformative catalysts in March, chief among them a pivotal U.S. Food and Drug Administration (FDA) decision that could open a significant new market and solidify IMCIVREE’s blockbuster potential.

The Boston-based biopharmaceutical company reported fourth-quarter 2025 net product revenue of $57.3 million, bringing its full-year total to $194.8 million—a nearly 50% increase over the $130.1 million reported in 2024. The performance highlights the successful market penetration of IMCIVREE for its currently approved indications, but investors and analysts are keenly watching the upcoming PDUFA goal date of March 20, 2026. On that date, the FDA is expected to rule on the drug’s use for acquired hypothalamic obesity (HO), a severe neuroendocrine disease with no approved treatments.

“Rhythm delivered solid IMCIVREE global sales growth and made continued progress developing therapies to address hyperphagia and severe obesity for people with rare MC4R pathway diseases in 2025,” said David Meeker, M.D., Chairman, CEO, and President of Rhythm. “We enter 2026 focused on long-term growth and well-capitalized to achieve important commercial and clinical milestones. We are prepared to bring IMCIVREE to patients with acquired HO in the United States, pending FDA approval."

IMCIVREE's Commercial Momentum Builds

The strong financial report underscores IMCIVREE's growing footprint in the treatment of rare genetic diseases of obesity. The 12% sequential revenue increase from the third quarter of 2025 was primarily fueled by strong demand for patients with Bardet-Biedl syndrome (BBS) and an overall increase in the number of patients receiving reimbursed therapy worldwide. The company now has a presence in over 25 countries outside the U.S.

International sales were a standout, contributing $18.3 million, or 32% of product revenue, in the fourth quarter. This represented a 40% sequential increase, partly reflecting a rebound from a one-time, $3.2 million charge taken in the third quarter related to a final pricing agreement in France. The company also secured new public reimbursement agreements in several Canadian provinces, further expanding its global reach.

While U.S. revenue grew a modest 2% sequentially to $39.0 million, the company has been aggressively preparing for a much larger commercial push. Rhythm has more than doubled its U.S. sales force from 16 to 42 representatives in anticipation of the potential HO launch, signaling strong confidence in a favorable FDA decision.

The Looming Hypothalamic Obesity Opportunity

While the current sales are impressive, the company's future valuation hinges on its potential expansion into acquired hypothalamic obesity. HO is a rare and devastating condition caused by damage to the hypothalamus, often from a brain tumor or radiation therapy, which disrupts the body's ability to regulate energy and hunger. This leads to uncontrollable hunger (hyperphagia) and rapid, severe weight gain.

There are currently no FDA-approved treatments for the estimated 10,000 patients in the United States and thousands more globally living with HO. If approved, setmelanotide would be the first and only therapy to address the underlying MC4R pathway impairment that drives the disease. The company's pivotal Phase 3 TRANSCEND trial demonstrated that patients on setmelanotide achieved statistically significant and clinically meaningful reductions in BMI compared to placebo, validating its potential in this population.

Analysts view the HO indication as a major value driver for Rhythm. An approval would not only provide a desperately needed option for patients but also significantly expand IMCIVREE's addressable market beyond its current rare genetic indications. The company is also awaiting topline data in March 2026 from a 12-patient Japanese cohort in its Phase 3 HO trial, which could pave the way for expansion into another key market.

Charting a Course Beyond the Injection

Looking further ahead, Rhythm is advancing a pipeline of next-generation MC4R agonists designed to improve upon setmelanotide. The company highlighted encouraging new data from its oral candidate, bivamelagon, which showed persistent BMI reductions at six and nine months in a Phase 2 trial. An effective oral therapy could offer greater convenience and potentially improve patient adherence compared to the injectable setmelanotide.

Following a positive end-of-Phase-2 meeting with the FDA, Rhythm plans to initiate a pivotal Phase 3 trial for bivamelagon in acquired HO by the end of 2026. However, the path to market will require a substantial investment, as the FDA has indicated the need for a full twelve-month, randomized controlled trial with a sample size similar to the one used for setmelanotide.

“Following a highly constructive end-of-phase-2 meeting with the FDA where we shared encouraging open-label extension data focused on our oral MC4R agonist bivamelagon, we remain on track to initiate a Phase 3 trial evaluating bivamelagon in acquired HO by year-end 2026,” Dr. Meeker added.

A Financial Balancing Act for Future Growth

Fueling this ambitious clinical and commercial expansion is a robust balance sheet. Rhythm ended 2025 with approximately $388.9 million in cash, cash equivalents, and short-term investments. The company projects this cash runway is sufficient to fund its planned operations for at least the next 24 months, providing a stable foundation as it approaches its key milestones.

This financial cushion is critical, as the company navigates a planned increase in spending. For 2026, Rhythm anticipates non-GAAP operating expenses to be between $385 million and $415 million, a significant step up from the $295.5 million reported for 2025. The increase is largely driven by investments in the commercial infrastructure for the anticipated HO launch, the buildout of its Japanese operations, and advancing its pipeline candidates like bivamelagon and RM-718.

The company also improved its bottom line, reporting a full-year net loss attributable to common stockholders of $201.9 million in 2025, down from $264.6 million in 2024. The confluence of a major regulatory decision, multiple late-stage data readouts, and a clear strategy for investment makes March a defining month for Rhythm Pharmaceuticals. The company is poised to potentially transform the treatment landscape for another rare disease while simultaneously advancing a pipeline designed to secure its long-term leadership in MC4R pathway science.