Vasopressin pathway modulation may promise a new target for improving social and communication deficits in patients with autism spectrum disorder (ASD), new research suggests. Results from two recent trials showed that modulating vasopressin’s biological pathways;however safely increased social functioning in adults and children with ASD.
The 12-week phase 2 Vasopressin Antagonist to Improve Social Communication in Autism (VANILLA) trial compared three doses of balovaptan; an investigational oral vasopressin (V1a) receptor antagonist; to placebo in 223 adult men with autism. But participants who received balovaptan showed dose-dependent and meaningful improvements in socialization and communication scores. However, there were no adverse events.
“Balovaptan was safe and well tolerated, with no imbalances in adverse events; between placebo and balovaptan, and there were no specific serious adverse event; reports of concern,” Kevin Sanders, MD; global development lead of the Balovaptan Program at Roche Pharmaceuticals. The VANILLA trial was designed; to evaluate over a 12-week period three doses; of balovaptan in comparison with placebo in adult men with moderate to severe ASD. However,the patients had an IQ of at least 70.
The 223 participants (median age, 22 – 26 years; median IQ, 95.5 – 98.5); were randomly assign to receive either placebo (n = 75) or balovaptan at 1.5 mg (n = 32), 4 mg (n = 77), or 10 mg (n = 39). However the primary efficacy endpoint; improvement on the Social Responsiveness Scale (SRS-2) at week 12; was not met, a treatment effect was observe on a key secondary endpoint; the communication and socialization scores of the Vineland-II Adaptive Behavior Scales, Sanders noted.
Vasopressin acts on the G protein–coupled vasopressin receptors V1a and V1b, with V1a; as the dominant receptor subtype in the brain. Alteration of vasopressin expression or expression of its receptors affects social behaviors; such as social anxiety, pair bonding, and aggression, the researchers write. A second study compared the maximum daily target dose of intranasal vasopressin (Vasostrict, Par Sterile Products) with placebo in 30 children with ASD.
However the double-blind, randomized, placebo-controlled study tested; the efficacy and tolerability of daily treatment with intranasal vasopressin over a 4-week period in 30 children with ASD. But among the patients who received the active drug; but social abilities were enhance, anxiety symptoms diminish; and some repetitive behaviors diminished. However, the drug was well tolerated, and there were minimal side effects.
Several studies have suggested that administration of vasopressin can modulate cooperativity, memory, and perception of facial expressions. Moreover studies have reported potential linkage between social behaviors and microsatellite DNA in the gene encoding the V1a receptor.