Aduhelm, produced by the Biogen laboratory, is the first Alzheimer's disease drug to have received marketing approval in the United States since 2003.
It is also the first to
address the causes of the disease.
But for some in the scientific
community, its benefit for patients has not been demonstrated.
This is a first in nearly
20 years.
On Monday, June 7, U.S.
health authorities authorized a new Alzheimer's disease drug manufactured by
the Biogen laboratory.
Baptized Aduhelm, this
antibody-based treatment was eagerly awaited by patients' associations who had
not seen anything new since 2003.
However, the release of
the drug has been greeted with dismay by a part of the scientific community,
which fears that the FDA may have been too quick to act.
FDA: the Food and Drug
Administration, the American drug regulator.
New drug: attacks disease supposed origin
Until now, all available
drugs have been aimed at treating the symptoms of this disease and have sought
to alleviate them.
Those symptoms include
progressive memory loss and difficulties in expressing oneself or thinking.
The treatment would get to
the root of the problem, potentially slowing the degenerative process.
It would offer a new ray
of hope to more than 30 million Alzheimer's patients worldwide.
"From a biological
point of view, according to Vincent Planche, an Alzheimer's specialist and
clinician at the University of Bordeaux.:
The results of Aduhelm are
quite spectacular.
The antibody does exactly
what it is asked to do, that is to say, it destroys the amyloid plaques in the brain.
These plaques, created by
the accumulation of beta-amyloid proteins produced in the brain.
They have been the main suspect
in the development of Alzheimer's disease since the early 1990s.
We speak of amyloid
cascades to designate this hypothesis explaining the disease," explains
Vincent Planche.
According to this dominant
theory, amyloid plaques play the role of a trigger that acts on another
substance in the brain.
These are the tau
proteins, which are responsible for doing the dirty work of "neuron
assassins", explains Tara Spires-Jones.
The administration of antibodies
can also have significant side effects.
There have been cases of
hemorrhages and strokes, as well as encephalitis, which has led to the
discontinuation of several clinical drug trials.
The cost of the New Alzheimer's drug
This data is according to
the Financial Times, the decision of the laboratory Biogen, which makes this
drug.
It is to position in terms
of price this drug at 56,000 dollars per year.
This is the price of new
drugs that use these methodologies, in particular these biotherapies.
The biotherapies require
extremely regular injections, every month, of these famous antibodies that are
extremely expensive to produce.
Now, we will have to phase
in its effectiveness.
Controversial results of Aduhelm
Biogen's Aduhelm passed
this test and was deemed "safe" after two phases of clinical trials.
This is one of the reasons
why the American FDA granted it a marketing authorization.
Specifying that the
"expected benefits are greater than the risks".
But the problem is that the
benefits for patients are far from being established with certainty.
The committee of
scientific experts convened to advise the FDA on the approval had also given a
negative opinion on its marketing.
First, Aduhelm had very
positive effects on animals.
Biogen then moved on to
the human testing phase, changing the protocol several times, "which is
never a good sign," notes Vincent Planche.
The laboratory conducted
two trials over 18 months with nearly 4,000 participants and provided
intermediate results to an independent analysis center.
The latter gave a very
severe verdict, judging that the drug "did not bring any benefit" to
patients.
But Biogen later retrieved
the results, added additional data from the trials and reported that one of the
tests.
In which patients received
a large dose of the antibody, showed a slight improvement in symptoms.
This is probably what
convinced the FDA, under pressure from patient associations, to override the
recommendations of its own expert committee.
The drug regulator has,
however, ordered Biogen to conduct a new clinical trial to confirm the data.
That leaves open the
possibility of withdrawal of approval in case of disappointing results.
Explore more Aduhelm by the Biogen laboratory
But for many experts, the
damage is already done. Several experts give their statements:
- John Harding:
The FDA's green light will
give the impression of new hope to millions of patients.
"It must be clear
that this drug will, at best, provide a small benefit to a small number of
hand-picked patients".
- Tara Spires-Jones:
"The FDA press
release does not indicate at what stage of the disease this treatment is
supposed to be effective, which is rare."
- Vincent Planche:
It is a drug for patients
at "a very early stage of the disease when there are not yet too many
amyloid plaques".
- Tara Spires-Jones:
The problem is that
"often when patients feel the first symptoms, it is already too late".
Aduhelm could therefore be
an effective drug, especially for patients who are unaware of it...
Sylvie Lorthois, a
biomechanic at the CNRS who has worked on Alzheimer's disease.
The FDA's decision may
also give the impression that acting on amyloid plaques is the only valid
avenue of research.
"Whereas there are still many things we
are not sure about in the functioning of this disease."
For her, the fact that
Aduhelm succeeds in reducing amyloid plaques without having a clear effect on
symptoms should push scientists to explore other avenues.
Ultimately, the solution
could come from a combination of treatments that act on both the plaques and
other factors.
That is including tau
protein or blood flow problems in Alzheimer's patients.
In short, she hopes that
the approval of this treatment is not the end of the road, but rather the
beginning of a new dynamic.
