Rhythm Pharmaceuticals has presented six-month data showing a reduction in weight and body mass index (BMI) from the long-term extension of the Phase II trial (NCT03651765) of Imcivree (setmelanotide) in patients with hypothalamic obesity.

Hypothalamic obesity is caused by genetic or physical damage to the hypothalamus, an area in the brain responsible for maintaining body functions such as metabolic rate.

Standard treatment may include pituitary hormone replacement, diet, exercise, weight management (surgical or medication), sleep, and psychosocial interventions.

According to the National Organization for Rare Disorders (NORD), no US Food and Drug Administration (FDA) approved treatments are specifically available for hypothalamic obesity.

The data was presented at the Endocrine Society Annual Meeting & Expo (ENDO 2023) in Chicago, US.

Imcivree helps stimulate the melanocortin-4 receptor (MC4R) pathway to reduce hunger and promote weight loss. It received FDA approval for Bardet-Biedl syndrome (BBS) or Alström syndrome in 2021.

Rhythm has partnerships with Genpharm, Medison Pharma, and RareStone to commercialise Imcivree in the Gulf region, Israel, and China, respectively.

Imcivree's six months data

The data was obtained from the 13 patients who reached six or more months on Imcivree in the extension arm of the 16-week open-label Phase II trial (16-week trial - NCT03013543) as of 30 November 2022.

A mean reduction in BMI of 16.8% and 21% were achieved at 16 weeks and six months from the baseline, respectively.

All 13 patients had a 5% or greater reduction in BMI, with ten patients having a 10% or greater reduction in BMI.

In the 11 paediatric patients (aged younger than 18 years), a decrease of 9.2kg and 3kg in fat and lean muscle mass, respectively, was recorded at 16 weeks.

As a result, Imcivree was well-tolerated, with no new safety concerns.

The US-based company also announced the pivotal Phase III trial design for Imcivree in hypothalamic obesity. The trial would aim to enrol 120 patients aged four years or older for 60 weeks, including eight weeks of dose titration. These patients would be randomised 2:1 to Imvcivree or placebo.