Early win means phase 3 test is on the way for Axovant's dementia drug

Analysts said the dementia drug's results beat expectations given the small sample size.

Positive results in a first crop of patients treated with its dementia drug have encouraged Axovant to start preparing for a phase 3 study.

So far 11 patients with Lewy body dementia (LBD) have been treated with nelotanserin, which is being developed to tackle the visual hallucinations and sleep disturbances that can afflict people with these diseases.

The results have outpaced expectations, with nelotanserin achieving a significant improvement in extrapyramidal symptoms—Parkinson's disease-like effects caused by the nerve degeneration in LBD—as measured by the Unified Parkinson's Disease Rating Scale (UPDRS), said the biotech.

The improvement over placebo in the crossover trial was seen even though only around half the target number of patients were recruited, and analysts at Jefferies said that can be seen as "beating expectations given the small sample size."

Final data are due mid-year, with the phase 3 trial due to start in the second half of the year, said Switzerland-based Axovant. If it proves to be successful the market opportunity could sizeable, as LBD as considered to be the second most common cause of dementia after Alzheimer's disease.

The company reckons there's a significant unmet need in patients with LBD in terms of controlling their Parkinsonism symptoms, without exacerbating psychiatric symptoms that can occur when treated with standard anti-Parkinson's drugs such as levodopa.

Results from a phase 2 trial looking at whether nelotanserin can tackle sleep disorders in LBD patents is also due later this year. With the latest data in hand, Axovant is now considering if it should add UPDRS as an endpoint in its phase 3 trial, along with the drug's impact on hallucinations and sleep quality.

LBD specialist James Leverenz, who is director of the Cleveland Clinic's Lou Ruvo Center for Brain Health, said the preliminary finding is intriguing.

"If a single drug could simultaneously address the motor and neuropsychiatric symptoms of LBD…it would represent a unique and important advance for the treatment of this condition," he said.

The serotonin 5HT2A receptor inverse agonist is sitting just behind Axovant's lead candidate intepirdine, a 5-HT6 receptor antagonist which is in the phase 3 MINDSET trial for Alzheimer's disease, in Axovant's pipeline.  

Intepirdine is, however, considered a high-risk project after similar drugs developed by Pfizer and Lundbeck failed late-stage trials, so the positive data for nelotanserin are a comfort to the biotech's investors.

Nelotanserin was originally developed for insomnia by Arena Pharmaceuticals, and while it failed to meet its targets in a phase 2 trial that earlier clinical experience means it has a fairly large safety database backing it up. Axovant licensed rights to the drug for neuropsychiatric uses in 2015.

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