Exciting New Research for Prader-Willi Syndrome

Janalee Heinemann, MSW
Director of Research & Medical Affairs 

There has been a lot of interest and excitement about three pharmacological products being researched that may have an impact on PWS.  One getting a lot of publicity is oxytocin. I know the researchers, Professor Maithé Tauber and Catherine Molinas from France, who recently published their results.  They sent me a copy of their full study, which will be reported on in the PWSA (USA) newsletter, The Gathered View.  Professor Tauber states, “Oxytocin is a key hormone in building social interactions and empathy.” and “Two days after administration of oxytocin, we noticed that our patients had increased trust, decreased sadness and showed less disruptive behavior.”  Because of space, we are holding on the report of the oxytocin study until the next edition.   

I have also been in touch with a researcher in Australia who are also doing a study on oxytocin.  The following is from the Australian researcher. 

“The OXT neurons seem to be good candidates for playing a physiological role in ingestive behavior as "satiety neurons" in the human hypothalamus.

•  One study provides further evidence for hypothalamic and oxytocinergic dysfunction in PWS. The associations between oxytocin, appetite regulation, and obsessive compulsive symptomatology in PWS warrant further investigation.

• We are currently conducting a trial of oxytocin nasal spray in PWS. We are still in the trial phase. Hopefully we will be able to form some conclusions by the end of the year.”
              ~Stewart L. Einfeld, Chair of Mental Health
              Senior Scientist, Brain and Mind Research Institute
              University of Sydney

The same researchers from France, Tauber and Molinas, also did the research on Modafinil (brand name Provigil) that we will be reporting on in the upcoming Gathered View.  Basically, it has been shown to be safe and effective in treating excessive daytime sleepiness in PWS. 

I am also keeping in touch with the research on Exenatide which is marketed as Byetta.  It is an analogue of the gut hormone GLP-1, that is normally released after a meal.  It is used as a novel daily injectable treatment for diabetes as it increases insulin secretion by directly acting on the pancreas. GLP-1 is what is called an ‘incretin’,  i.e. increases insulin.  It seems to have an advantage over some other diabetes medicines in that (like metformin) it does not cause weight gain and may even cause mild weight loss of under 5%.  

It is unclear if this weight loss is just due to delaying stomach emptying (and so increase ‘fullness’) or also by its actions on nerve cells in the brainstem directly or indirectly via the vagus nerve to reduce appetite. A concern would be that many people with PWS already have delayed stomach emptying. So there is a theoretical risk of this getting worse with Byetta treatment in PWS, which might increase the risk of gastric necrosis associated with severe overeating.  

An Australian group is doing a clinical trial on Exenatide (Byetta), the UK reported a positive case study, and Children’s Hospital of Los Angeles will be looking at the effects of different obesity markers after six months of treatment with Byetta.

edited: 02/09/2012