Safety and Tolerability of SRX246, a Vasopressin 1a Antagonist, in Irritable Huntington\u27s Disease Patients-A Randomized Phase 2 Clinical Trial.

SRX246 is a vasopressin (AVP) 1a receptor antagonist that crosses the blood-brain barrier. It reduced impulsive aggression, fear, depression and anxiety in animal models, blocked the actions of intranasal AVP on aggression/fear circuits in an experimental medicine fMRI study and demonstrated excellent safety in Phase 1 multiple-ascending dose clinical trials. The present study was a 3-arm, multicenter, randomized, placebo-controlled, double-blind, 12-week, dose escalation study of SRX246 in early symptomatic Huntington\u27s disease (HD) patients with irritability. Our goal was to determine whether SRX246 was safe and well tolerated in these HD patients given its potential use for the treatment of problematic neuropsychiatric symptoms. Participants were randomized to receive placebo or to escalate to 120 mg twice daily or 160 mg twice daily doses of SRX246. Assessments included standard safety tests, the Unified Huntington\u27s Disease Rating Scale (UHDRS), and exploratory measures of problem behaviors. The groups had comparable demographics, features of HD and baseline irritability. Eighty-two out of 106 subjects randomized completed the trial on their assigned dose of drug. One-sided exact-method confidence interval tests were used to reject the null hypothesis of inferior tolerability or safety for each dose group vs. placebo. Apathy and suicidality were not affected by SRX246. Most adverse events in the active arms were considered unlikely to be related to SRX246. The compound was safe and well tolerated in HD patients and can be moved forward as a candidate to treat irritability and aggression

MS vs. HD: Can white matter and subcortical gray matter pathology be distinguished neuropsychologically?

This study was conducted to examine the neuropsychological effects of white matter and subcortical gray matter pathology. Nineteen patients with multiple sclerosis (MS), 16 with Huntington\u27s disease (HD), and 17 normal controls (NC) participated. Participants completed the California Verbal Learning Test (CVLT), Rotary Pursuit (RP) and Mirror Tracing (MT) tasks, and the Symbol Digit Modalities Test (SDMT). The principal findings pertain to a dissociation in procedural memory: on RP, the HD group demonstrated impaired sequence learning compared to the MS group, which performed similarly to the NC group, yet on MT, the MS and HD groups demonstrated normal perceptual-motor integration learning. On the CVLT, both patient groups performed better on recognition than on recall. On the SDMT, both patient groups performed worse than the NC group, with the HD group performing more poorly than the MS and NC groups. These results suggest that involvement of white and subcortical gray matter may produce different neuropsychological effects. © 2006 Psychology Press

By Carrot or by Stick: Cognitive Reinforcement Learning

19. M. Uhlirova et al., Proc. Natl. Acad. Sci. U.S.A. 100, 15607 (2003)

Safety and Tolerability of SRX246, a Vasopressin 1a Antagonist, in Irritable Huntington’s Disease Patients—A Randomized Phase 2 Clinical Trial

SRX246 is a vasopressin (AVP) 1a receptor antagonist that crosses the blood-brain barrier. It reduced impulsive aggression, fear, depression and anxiety in animal models, blocked the actions of intranasal AVP on aggression/fear circuits in an experimental medicine fMRI study and demonstrated excellent safety in Phase 1 multiple-ascending dose clinical trials. The present study was a 3-arm, multicenter, randomized, placebo-controlled, double-blind, 12-week, dose escalation study of SRX246 in early symptomatic Huntington’s disease (HD) patients with irritability. Our goal was to determine whether SRX246 was safe and well tolerated in these HD patients given its potential use for the treatment of problematic neuropsychiatric symptoms. Participants were randomized to receive placebo or to escalate to 120 mg twice daily or 160 mg twice daily doses of SRX246. Assessments included standard safety tests, the Unified Huntington’s Disease Rating Scale (UHDRS), and exploratory measures of problem behaviors. The groups had comparable demographics, features of HD and baseline irritability. Eighty-two out of 106 subjects randomized completed the trial on their assigned dose of drug. One-sided exact-method confidence interval tests were used to reject the null hypothesis of inferior tolerability or safety for each dose group vs. placebo. Apathy and suicidality were not affected by SRX246. Most adverse events in the active arms were considered unlikely to be related to SRX246. The compound was safe and well tolerated in HD patients and can be moved forward as a candidate to treat irritability and aggression