Setmelanotide in BBS
Advances in the Treatment of Bardet-Biedl Syndrome

Released: January 09, 2023

Expiration: January 08, 2024

Stephanie Sisley
Stephanie Sisley, MD

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Key Takeaways

  • Bardet-Biedl syndrome compromises satiety pathways and can cause weight gain in pediatric patients.
  • Setmelanotide is approved to help reduce hyperphagia in pediatric patients with Bardet-Biedl syndrome.
  • Patients who are starting setmelanotide should be counseled on use of the medication, as well as common adverse events such as hyperpigmentation.

Pediatric patients with Bardet-Biedl syndrome (BBS) struggle with the drive to eat because their satiety pathways don’t work properly. This can also affect their ability to self-regulate food intake. The fact that there is a medical treatment that could potentially help patients younger than 12 for whom currently no other approved treatments for obesity exist, with one of the underlying components of their weight gain, is really exciting.

Although the numbers were small, a study of setmelanotide showed that 86% of the children in the study actually had a meaningful 0.2 reduction of their BMI z-score. Some newer data showed that 100% of the patients kept that reduction in BMI z-score change for 2 years, which is really important in children. In adults, the study found that, on average, 21 pounds were lost over 2 years.

When I counsel parents, I tell them that this is a drug that will potentially help their child feel full because it is designed to affect satiety, which we know is one of the likely causes of weight gain in patients with BBS. I also stress that the drug is just one piece of the puzzle, and that a healthy diet and increased activity are extremely important for the overall management of weight.

Setmelanotide is administered by daily injection. In our experience, children do really well with it after the initial adjustment. Some patients might have a couple of days of mild stomach pain. The most common adverse event I see is hyperpigmentation of the skin, meaning that their skin becomes darker and they look tan. Parents have told me their child was not bothered by this until other people start mentioning it to them. Since those people tend to be family, I now advise parents to talk to family members about the fact that the child is receiving a medication that causes changes in their skin tone and to not emphasize it to the child due to the risk of making him or her self-conscious. 

Hyperpigmentation will continue until the patient is off the medication. In my experience, the full effect of the skin darkening takes approximately 3 months. I also counsel parents that areas where the skin becomes irritated can temporarily become more hyperpigmented. It will fade over time but may take a couple of weeks to resolve. For some patients, picking or scratching at their skin is a part of their syndrome, so this is an important counseling point. In my experience, these adverse events are manageable and families have been really pleased with the overall effect of the drug.

I think that it’s generally important for physicians to be aware of options to help kids and adults with obesity and to present those options to patients who could potentially benefit from them. It can be challenging to determine what will work best for your particular patient. I find that it helps to understand that some patients are really struggling with underlying physiologic changes and will likely need medical intervention to overcome that change to be successful with weight loss.

However, given that BBS is a rare syndrome, and primary care practitioners might only have one patient in their practice with this diagnosis, treating that one patient might seem daunting. In that case, partnering with or referring that patient to someone more experienced with the treatment of genetic causes of obesity might make sense. I know that I personally would be more than happy to talk to a physician and share my experience or serve as a consultant. In many places, there may be a substantial wait for a patient to see a specialist, and I think a lot of other physicians would be willing to partner as well. So do not be afraid to reach out to others for help or advice if needed.

Your Thoughts?
In your practice, how often would you initiate setmelanotide for a patient with BBS to achieve and maintain a healthy weight? Answer the polling question and join the discussion by posting a comment.

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