Memantine: Memory Medicine
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RAY SUAREZ: Next, a look at a drug that may help slow the toll of Alzheimer’s. The government today approved the first drug in the U.S. for treating patients who are suffering from moderate to severe Alzheimer’s disease. It’s called memantine. Nearly 4.5 million Americans have Alzheimer’s disease, and researchers say that number is expected to triple by 2050.
More now about the drug and the role it may play from Dr. Paul Aisen. Dr. Paul Aisen is director of the memory disorders program at Georgetown University medical center. His center was one of the test sites for memantine. First, how do you say the name? I keep saying it different ways.
DR. PAUL AISEN: Memantine
RAY SUAREZ: Okay. What did the clinical trials that paved the way for the approval show?
DR. PAUL AISEN: There were three large clinical trials that enrolled hundreds of people with Alzheimer’s disease at the moderate to severe stage as you said. The studies clearly show that there are meaningful gains with use of this drug that is compared to people taking a placebo those would took memantine showed stabilization in cognitive function, in behavior, in activities of daily living, and importantly using the drug was helpful in reducing the burden on care givers which is very important in this disease.
RAY SUAREZ: If I understand you correctly it was putting on the brakes in the progress of the disease rather than restoring any lost abilities?
DR. PAUL AISEN: There was actually some symptomatic improvement, so you could see benefit but the benefit is modest and this is not a cure. I think the benefit is important. I think this is a significant step forward but it does not stop the progression of disease. That’s right; the disease still continues to worsen.
RAY SUAREZ: What symptoms does it go to work on. How does it do it? What systems in the body does it interact with?
DR. PAUL AISEN: Alzheimer’s disease is a diffused brain disorder. It involves many pathways in the brain; many neurotransmitters are involved. They are the chemicals that allow communication between brain cells.
The first class of drug used — all the drugs available prior are involved in acetylcholine, the neurotransmitter acetylcholine. Memantine is the first drug that targets a second neurotransmitter called glutamate. What that means — the mechanism is distinct. It has a general effect on cognition and behavior and function. And it has an additive effect — that is memantine can be used in combination with the older drugs.
RAY SUAREZ: Those older drugs, do they phase out at some point; would patients transfer from one to the other generally?
DR. PAUL AISEN: The older drugs that we refer to as cholinesterase inhibitors. These drugs are approved for the treatment of mild to moderate disease. Memantine is now approved for moderate to severe disease. There’s an overlap.
People at the moderate stage would be appropriate candidates for using the older drugs and memantine and perhaps for the combination because one of trials conducted looked at memantine in combination with an older drug and it seemed to have an added benefit.
In the early stage of disease, at the mild stage, cholinesterase inhibitors are the best treatment. In the moderate stages those drugs are continued and memantine might be added and memantine is the first drug shown to be effective at the severe stage.
RAY SUAREZ: Alzheimer’s remains an incurable disease; this drug would be considered what, a palliative, a treatment of symptoms?
DR. PAUL AISEN: That’s correct. The benefits are symptomatic although because glutamate, the molecule that’s targeted by memantine, is thought to contribute to the damage of disease there’s a hope you are actually slowing down the process but you are certainly not stopping it.
The disease does progress. And, yes, I think you could consider memantine to be palliative in that sense. But we’re optimistic. We think we’re getting closer to actually controlling the disease process too. It may be that in the foreseeable future we actually can stop the disease from progressing.
RAY SUAREZ: Is Alzheimer’s so severe and certainly in the kind of advanced patients that you are talking about so destructive that side effects become less of an issue when you’re looking for a drug to help treat symptoms?
DR. PAUL AISEN: No side effects are always important. The clinical trials that have been done with memantine always weigh benefits and risks. There can be side effects at any stage of disease.
It’s clear though from the three large memantine trials that this drug has benefits that outweigh the risks. The risks were actually quite small, quite modest. I think it is clear that this drug is beneficial for people with moderate to severe AD.
RAY SUAREZ: What about places where it’s been in use for a longer time? I understand in Europe it was approved for use earlier. Do we get anything worthwhile, some information useful from watching other places that have already been taking it?
DR. PAUL AISEN: Memantine has been used for quite a number of years in Europe. It was developed in Europe and it was approved by the European Union in 2002. We did get experience; there were trials done in Europe and in fact one of trials considered by the FDA was a European trial. We did learn from the experience in Europe and confirm the benefit of memantine and refined its use with large trials conducted here in the U.S.
RAY SUAREZ: So if you are a care give, if you are an early stage sufferer yourself should you contact a doctor and talk about memantine and the promise that it may hold for you individually?
DR. PAUL AISEN: I think it is worth talking about memantine. I think it does represent a significant step forward. The first of a new class, a new option for treatment of Alzheimer’s disease not so much at the mild stage but at the moderate to severe stage. Yes, I think that care givers, family members people who have the disease should take to their doctors about this new option that we have for treatment.
RAY SUAREZ: And what about the next generation of things? Are there things that we understand now about the disease and its progression that gives us a clue on where to look next for the cure?
DR. PAUL AISEN: I think that’s what is most exciting. I think that we really do have a good idea about the cause of the disease, about the molecule that starts the process of damage in the Alzheimer’s disease brain and I think we have a good idea thousand design new drugs that may actually get rid of that molecule — that actually removes the inciting event and we may be close to a real breakthrough in treatment.
RAY SUAREZ: Dr. Aisen, thanks for being with us.
DR. PAUL AISEN: Thank you.