Hamamatsu Medical University and others confirm the safety and efficacy of oxytocin nasal sprays for treatment of autism spectrum disorder

People with autism spectrum disorder (ASD) have symptoms such as interpersonal communication disorders, which include difficulties in grasping the feelings of others by utilizing facial expressions and voice cues. They also often show stereotyped and limited interests which tend to be biased and the same behaviors are likely to be repeated. ASD is a developmental disorder that occurs in 1 in 54 people. No cure has been established.

In collaboration with Hokkaido University Hospital (Specially Appointed Professor Takuya Saito), Tohoku University (Associate Professor Nami Honda), The University of Tokyo (Associate Professor Yukiko Kano), Nagoya University (Professor Takashi Okada, currently Director of National Institute of Mental Health, National Center of Neurology and Psychiatry), Osaka University (Professor Manabu Ikeda), and Kyushu University (Professor Toshiaki Onitsuka), Professor Hidenori Yamasue of the Department of Psychiatry, Hamamatsu University School of Medicine, conducted an investigator-initiated clinical trial of an improved oxytocin nasal spray in collaboration with Teijin Pharma. Their findings confirmed the efficacy and safety of the improved oxytocin nasal spray which is expected to be the first treatment for the core symptoms of autism spectrum disorders. These findings were published in BRAIN.

Studies conducted in Europe, the United States, and Japan have reported that a single dose of oxytocin was effective for social communication disorders. However, there were discrepancies in the results, such as no effect after repeated administration, or there was an effect in the secondary endpoint but no efficacy in the primary endpoint. The research group hypothesized that the reason for the varying results was that, in addition to the attenuation of the effect of oxytocin by repeated doses, the dose that gives the maximum effect with a single dose may not be the optimal dose for repeated doses. They developed an improved nasal spray with Teijin Pharma and conducted an investigator-initiated clinical trial. This nasal spray was examined in the brain of rabbits by Teijin and it was confirmed that it was 3.6 times more likely to be transported to the brain than the existing formulation.

The trial involved 109 individuals, divided into eight groups according to placebo, dose, and time of administration, and was conducted from June 2018 to March 2020. They discovered for the first time that the dose-response relationship between the oxytocin dose and the ameliorating effect of oxytocin on ASD core symptoms is U-shaped. A single dose of the conventional formulation was shown to be the most effective, with approximately half of the dose showing the greatest improvement effect.

Dr. Okada said the following about the improvements seen in patients. "I was quite happy that the families were very surprised and pleased. We've heard reports of subtle, but important, behavioral changes, including patients offering to help their parents to carry heavy things, or asking what they were recording when watching TV." Professor Yamasue said, "I think that the fact that our analysis included participants who experienced protocol deviations, such as failure to follow the prescribed administration method, makes our study quite similar to treatment that will likely occur in the real-world clinical environment. We would like to conduct a larger clinical trial so that such analyses can show significant improvement. We are looking for a corporate partner to cooperate with in the next stage of clinical trials and hope to achieve regulatory approval of the improved oxytocin nasal spray."