The US Food and Drug Administration (FDA) has extended the review period for expanded approval of Rhythm Pharmaceuticals’ Imcivree (setmelanotide) for a form of obesity caused by damage to the brain.
The company had been hoping to know whether its lead product would gain a label extension to treat acquired hypothalamic obesity by 20 December 2025, but the FDA has pushed back the Prescription Drug User Fee Act (PDUFA) goal date to 20 March 2025.
Rhythm’s stock dipped 6.2% to $98.43 per share at market open on 7 November following the PDUFA delay, compared to a $104.99 market close on 6 November. The pharma company has a market cap of $6.4bn.
The review extension comes as the FDA has asked the pharma company for additional sensitivity analyses of clinical efficacy data from the Phase III TRANSCEND trial (NCT05774756) that evaluated Imcivree in patients with acquired hypothalamic obesity.
Hypothalamic obesity is a rare disorder caused by damage to the hypothalamus in the brain, leading to uncontrollable weight gain due to excessive hunger and a lowered metabolic rate.
TRANSCEND met its primary endpoint of reduction in body mass index (BMI) in both adult and paediatric patients versus placebo, according to an April 2025 readout.
Though the FDA has requested no new data, the additional information reflects a major amendment to Rhythm’s supplemental new drug application (sNDA), allowing the FDA more time to go over the submission. There were no safety concerns or manufacturing issues, meaning the extra analyses is all Rhythm is tasked with completing.
Rhythm’s CEO David Meeker said: “Imcivree has demonstrated a compelling product profile, and we have every confidence that these additional sensitivity analyses confirm the strength of the data and Imcivree’s potential to benefit patients with hypothalamic obesity.”
Given as an injection, Imcivree is Rhythm’s sole FDA-approved product. The melanocortin 4 (MC4) receptor agonist is indicated for chronic weight management in adults and certain paediatric patients with monogenic or syndromic obesity due to disorders. These include Bardet-Biedl syndrome (BBS) or deficiencies in pro-opiomelanocortin (POMC) or leptin receptor (LEPR) genes – both disorders lead to obesity, amongst other symptoms. An expansion into hypothalamic obesity would mark the first approved therapy for the disorder.
Meeker added: “We appreciate and continue to collaborate with the FDA review team and we also are continuing to advance our preparations to deliver Imcivree to a patient community that currently has no treatment options approved for acquired hypothalamic obesity.”
Imcivree’s sales and continued positive trial readouts have fuelled significant growth for Rhythm over the past year. Imcivree generated sales of $51.3m in Q3 2025, up 6% from Q2 2025. This figure is also up a hefty 35% on the $33.3m from Q3 2024.
Net revenues for Imcivree totalled $137.5m for the nine months of 2025, up a similar 36% from the $88.3m during the same period last year.
Growth is expected to continue for the drug, particularly if the FDA approves the hypothalamic obesity indication. With sales predicted to reach $1.2bn, Imcivree is forecast to reach blockbuster status by 2030, according to GlobalData’s Pharma Intelligence Center.
GlobalData is the parent company of Pharmaceutical Technology.
