Rhythm Pharmaceuticals announced today that it has reacquired the licensing rights to IMCIVREE® (setmelanotide) in China, including mainland China, Hong Kong, and Macau, following the termination of its 2021 licensing agreement with RareStone Group Ltd.
Under the terms of the agreement, Rhythm will pay RareStone $6.3 million in cash and return all previously acquired RareStone shares for no additional consideration. This strategic move gives Rhythm complete global control over the development and commercialization of setmelanotide.
"Rhythm continues to execute on our strategy of developing setmelanotide and the next generation of MC4R agonists with the goal of making these treatments available to patients from around the world who may benefit," said David Meeker, MD, Chairman, CEO and President of Rhythm. "Our global trial of setmelanotide in patients with acquired hypothalamic obesity – which is on track for topline data readout in the second quarter of 2025 – is being conducted in North America, Europe and Japan, and this reacquisition of rights for China, Hong Kong and Macau means Rhythm now owns the global franchise."
Expanding Global Reach for Rare Disease Treatment
IMCIVREE is a melanocortin-4 receptor (MC4R) agonist designed to treat hyperphagia and severe obesity in patients with rare genetic conditions. The drug has received regulatory approvals in multiple markets for specific indications.
In the United States, IMCIVREE is approved to reduce and maintain weight reduction in adult and pediatric patients aged 2 years and older with obesity due to Bardet-Biedl syndrome (BBS) or genetically confirmed pro-opiomelanocortin (POMC), proprotein convertase subtilisin/kexin type 1 (PCSK1), or leptin receptor (LEPR) deficiency.
Similarly, both the European Commission and the UK's Medicines & Healthcare Products Regulatory Agency have authorized setmelanotide for treating obesity and controlling hunger in patients with genetically confirmed BBS or loss-of-function biallelic POMC, PCSK1, or LEPR deficiency.
Strategic Implications for Clinical Development
The reacquisition comes at a pivotal time for Rhythm, as the company is advancing a Phase 3 clinical trial evaluating setmelanotide in patients with acquired hypothalamic obesity. This condition, which can develop after damage to the hypothalamus from tumors, surgery, or radiation therapy, currently has no approved pharmacological treatments.
The global study is being conducted across sites in North America, Europe, and Japan, with topline data expected in the second quarter of 2025. By regaining the rights in China, Rhythm positions itself to potentially include Chinese patients in future trials and streamline global regulatory strategies.
Expanding the MC4R Pipeline
Beyond setmelanotide, Rhythm is advancing additional MC4R agonists, including investigational compounds LB54640 and RM-718. The company is also developing a preclinical suite of small molecules targeting congenital hyperinsulinism, further expanding its focus on rare neuroendocrine diseases.
Safety Considerations
As with any pharmaceutical product, IMCIVREE carries certain risks. The most common adverse reactions reported in clinical trials included skin hyperpigmentation, injection site reactions, nausea, headache, diarrhea, abdominal pain, vomiting, depression, and spontaneous penile erection.
More serious warnings include the potential for disturbance in sexual arousal, depression and suicidal ideation, hypersensitivity reactions, and skin hyperpigmentation including darkening of pre-existing nevi and development of new melanocytic nevi.
Market Impact
This reacquisition represents a significant strategic move for Rhythm Pharmaceuticals, which is headquartered in Boston. By consolidating global rights to IMCIVREE, the company strengthens its position in the rare disease space and potentially simplifies its regulatory and commercial strategies worldwide.
"I want to thank the current management of RareStone for their efforts in reaching a mutually acceptable agreement," added Dr. Meeker, highlighting the collaborative nature of the termination.
The financial terms of the deal – $6.3 million plus the return of RareStone shares – appear relatively modest compared to the potential strategic value of having complete global control over the IMCIVREE franchise, particularly as Rhythm advances its clinical programs in additional indications.
