TauRx hits milestone in mild Alzheimer's trial

Singapore-based TauRx has completed enrolment in a second pivotal trial of its Alzheimer's disease (AD) candidate LMTX, setting it on course for a data read-out in early 2016.

TauRx is bucking the trend among most pharmaceutical companies by focusing its development programme on tau protein, which forms characteristic tangles in the brains of people with AD, rather than amyloid protein which has been the target of the lion's share of research dollars in recent years.

The biotech - which span out of the University of Aberdeen in Scotland - has now enrolled 700 patients into its Phase III mild AD trial, having already met its target tally of more than 830 patients in a second study involving patients with both mild and moderate AD symptoms in July.

TauRx' chairman and co-founder Claude Wischik, professor of old age psychiatry at the University of Aberdeen in Scotland, said having two fully-enrolled trials is "a major milestone" for the company, which has been working on the development of LMTX for more than a decade.

Despite being established as a potential drug target for AD for around 30 years, tau has been downplayed compared to amyloid and TauRx something of a lone supporter of the hypothesis that it could have an impact on AD and other forms of dementia.

Now, with number of failures for amyloid-targeting drugs mounting and proponents of the amyloid hypothesis arguing that they must be delivered earlier and earlier in the course of the disease to have an impact, the pendulum may be starting to swing the other way.

"Having a tau-targeted treatment that slows or halts the progression of Alzheimer's will be a breakthrough for people facing this disease worldwide," commented Serge Gauthier of the McGill Centre for Studies in Aging in Montreal, Canada, who is one of the lead investigator's in the LMTX development programme.

"With many failed attempts in alternative approaches, we could at last be on the right path towards altering the underlying pathology that leads to dementia."

TauRx is clearly leading the field among tau protein-targeting therapies, but other companies are starting to look more closely at the protein.

For example, Eisai and Biogen Idec announced a partnership to develop a pair of AD antibodies - one targeting amyloid and the other blocking tau protein - in March, while in January private Swiss firm AC Immune started trials of ACI-35, a drug designed to stimulate the body's immune system to produce antibodies which target the tau protein. Axon Neuroscience is also developing a tau-targeting immunotherapy called AADVac-1 that has reached Phase I trials.

It should be noted however there have been some disappointing developments for the tau devotees too. Earlier this year Zeltia's tideglusib - an orally available, small-molecule of the tau kinase glycogen synthase kinase 3 (GSK-3) - failed to show efficacy in a Phase II trial involving 308 patients with mild-to-moderate AD and has been discontinued.

Meanwhile, Bristol-Myers Squibb's epothilone D and Allon Therapeutics/Paladin Laboratories davunetide are two mother tau-targeting compounds that have been dropped from clinical development for AD or other forms of dementia.

TauRx remains confident however and whilst waiting for the AD trials to generate results is now turning its attention towards a third Phase III trial of LMTX in behavioural variant fronto-temporal dementia (bvFTD), which should complete enrolment next year.

"Patients and families living with bvFTD are encouraged to contact the nearest research centre to be included in this Phase III clinical trial before the window of opportunity closes shortly," said Wischik.