Oxytocin is a currently a very hot topic in PWS research. It is also a great example of the scientific process in action, with recent results providing complex and sometimes conflicting information. Researchers are working hard to determine if and how intranasal oxytocin and related compounds may benefit those with PWS. We all remain hopeful that current studies will shed some light on this complex pathway and begin to address some of the many unanswered questions.
The hormone oxytocin plays a critical role in many aspects of human behavior. It is often referred to as the “love” hormone, contributing to mother-infant bonding in newborns. However, research shows that oxytocin also increases trust, optimism and social interaction. As a result, its use as a therapy in treating behavior and social disorders is being actively studied around the world. This includes autism spectrum disorder (ASD), schizophrenia, social anxiety in Fragile X syndrome, and others.
There are several lines of reasoning that support asking whether oxytocin may benefit those with PWS. First, those with PWS have fewer than normal oxytocin-producing neurons in the hypothalamus region of the brain (Swaab, 1997). Second, ASD type behavioral issues are common in PWS and have a huge impact on quality of life (Dykens, 2011). Third, oxytocin also plays a role in normal appetite control, with increased levels of oxytocin bringing decreased appetite (Sabatier, 2013). Therefore, it is possible that oxytocin could potentially improve both behavior and hyperphagia in PWS.
To date, two clinical trials of intranasal oxytocin in PWS have been published. The first, by Dr. Maithe Tauber and colleagues in France, was the topic of an FPWR research blog post in 2011. This was a small study with a primarily goal of determining if intranasal oxytocin is safe. 24 adults were given a single dose of oxytocin and then evaluated for 2 days for social skills and behavior (e.g. trust, sadness, interpersonal conflicts). Overall, the oxytocin was well tolerated and didn’t cause side effects. The results were promising in that there was a trend toward improved social skills scores in individuals after oxytocin treatment. The difference compared to placebo wasn’t statistically significant immediately after treatment, but was significant at two days post oxytocin.
Following the single-dose Tauber trial, a group in Australia led by Dr. Stewart Einfeld ran a study to see if longer term treatment might provide more benefit. This trial enrolled 30 participants (ages 12-30) who each received 8 weeks of oxytocin and 8 weeks of placebo. The results were just recently published and did not show significant improvements in any of the measures (e.g. behavior, OCD, hyperphagia). In fact, the higher dose of oxytocin was associated with an increase in temper outbursts.
Although results from the two completed trials are not consistent, many researchers are still optimistic about the potential benefit of oxytocin treatment in PWS. Oxytocin signaling is very complex and determining if intranasal oxytocin will work as a therapy is going to take time and additional study. These studies will be testing a number of variables including the formulation of oxytocin, dose (for example, lower doses may be better than higher), the optimal age for treatment, nutritional phase, genetic subtype and other factors. In fact, an additional study using a slightly different form of oxytocin has recently been completed by Ferring Pharmaceuticals. We look forward to those results being reported and to the possibility of additional trials using that compound.
There are upcoming opportunities to participate in oxytocin trials, and we are the key that will help researchers unlock this black-box! For more information on ongoing clinical trials of oxytocin, please visit FPWR clinical trials page here, and subscribe to FPWR's clinical trial alert here.