Sleepiness Clinical Trial Suggests Wake-Promoting Properties
Vanda Pharmaceuticals announced top-line results from Proof- of-Concept Phase II clinical trial evaluating VSF-173 in a clinical model of excessive sleepiness.
This Phase II study examined the effects of VSF-173 on a model of excessive sleepiness among 55 healthy volunteers treated with 3 doses of VSF-173 administered at 50 mg, 100 mg and 200 mg and placebo administered at 25 mg, 50 mg and 100 mg at the usual bedtime and at four hours after the first dose. In this model, the effect of the compound was evaluated with a series of six Maintenance of Wakefulness Tests (MWT) given two hours apart starting one hour after the first dose. The effect of the drug was also evaluated on the scheduled daytime recovery sleep following the night time and morning evaluations.
On the primary endpoint which evaluated the effect of the compound on the first four series of MWT tests, VSF-173 demonstrated improvements over placebo. The mean MWT sleep onset scores for the 50 mg, 100 mg and 200 mg, and placebo groups were 10.3, 12.9, 10.6 and 9.2 minutes, respectively. While the pair-wise analysis did not reach statistical significance, this magnitude of effect, ranging from 1.1 to 3.7 minutes, is generally similar to that observed with modafinil in the treatment of patients with narcolepsy.
In a subset of 37 subjects with no observed impairment in pre-dose daytime wakefulness (MWT cutoff equal to 30 minutes), the mean of all six MWT scores for the 50 mg, 100 mg and 200 mg groups showed improvements of 2.1, 3.4 and 2.1 minutes, respectively, compared to placebo. For the dose group of 100 mg, this observation of improvement was statistically significant (p < 0.05).
Further evidence of the wake-promoting properties of VSF-173 was also observed during the scheduled daytime recovery sleep following the night time and morning evaluations. Statistically significant (p<.05; non-parametric) dose-dependent correlations were observed with the following polysomnography (PSG) parameters: increased number of awakenings, decreased sleep efficiency and total sleep time for the first third of the sleep period, and increased wake time after sleep onset for the first 3 hours of the sleep period.
These wake-promoting effects of VSF-173 on MWT and PSG measures suggest that VSF-173 possesses a novel mechanism to address disorders of excessive sleepiness. Vanda plans to conduct additional studies to further understand timing of administration, dose-response and appropriate populations to treat. VSF-173 was also demonstrated to be safe and well-tolerated.
"We are encouraged by the results of this proof-of-concept study on VSF-173," stated Mihael Polymeropoulos, M.D., President and CEO of Vanda. "We believe that the compound has the potential to address the symptoms of excessive sleepiness in the context of a number of disorders including narcolepsy and shift worker sleep disorder, as well as neurodegenerative disorders."