LONDON Nov 23 The failure of an experimental
Alzheimer's drug from Eli Lilly to slow cognitive
decline, as many had hoped, has cast doubt on a main approach to
fighting the disease, yet experts believe subtly different
therapies could still work.
Lilly's injectable antibody medicine solanezumab was
designed to mop up a protein called beta amyloid that forms
plaques in the brain and is believed to play a pivotal role in
Other anti-amyloid drugs are also in clinical trials but
they function in slightly different ways and, importantly, some
are being tested at an earlier stage when there may be a better
chance of improving brain function. Drug doses also vary.
"This is probably not the end for amyloid approaches," said
Elizabeth Coulthard, a dementia specialist at the University of
Bristol, who nonetheless acknowledged the late-stage Lilly trial
result was "very disappointing".
John Hardy, professor of neuroscience at University College
London, said the focus would now shift to another class of
experimental drugs called BACE inhibitors, which are given as
pills and work differently to block beta amyloid production.
Merck is currently leading in the BACE inhibitor
race with its product verubecestat, which is being tested in two
late-stage Phase III trials, the first of which is expected
report results next year.
Lilly is also working on a rival BACE medicine with
Other companies with antibody treatments targeting beta
amyloid in development include Biogen and Roche
, which has a tie-up with biotech firm AC Immune
Shares in these rival companies fell in the wake of the
Lilly setback, as conviction in the beta amyloid treatment
The failure is particularly disappointing given positive
news last year suggesting that solanezumab might become the
first drug ever to slow the progression of Alzheimer's.
Currently approved drugs can do no more than ease some of
the symptoms of the disorder and a successful disease-modifying
treatment would be virtually guaranteed multi-billion dollar
annual sales, industry analysts believe.
To date, however, the field has been littered with failures.
An analysis last year by the Pharmaceutical Research and
Manufacturers of America found that between 1998 and 2014, 123
potential Alzheimer's drugs were halted in clinical trials,
while just four were approved.
Still, drug companies continue to lay bets in the hope of
eventually tapping a huge market, with more than 70 experimental
treatments in various stage of clinical testing.
"This is only one drug of several in the pipeline and they
aim to tackle dementia in different ways, so we should not lose
hope," Jeremy Hughes, chief executive of Britain's Alzheimer's
Society, said in response to the Lilly news.
Although the precise causes of Alzheimer's are unclear,
scientists believe the evidence implicating beta amyloid remains
strong, although earlier-stage research is also focused on
another protein called tau.
Experts will pore over detailed data when full results from
the Lilly study are presented at a medical meeting next month,
since while there was no statistically significant benefit over
placebo, there was a directional trend favouring solanezumab.
(Editing by Giles Elgood)