What is memantine? Memantine is a drug approved in October 2003 by the U.S. Food and Drug Administration (FDA) for treatment of moderate to severe Alzheimer's disease. Forest Laboratories Inc., memantine's U.S. developer, will market the drug under the trade name Namenda®. Memantine was first approved in Germany for treatment of various neurological disorders in 1982, where it is marketed by Merz + Co. as Axura®. Since 2002, it has been approved in the rest of the European Union, where it is marketed by Lundbeck as Ebixa®. Forest anticipates that memantine will be available in U.S. pharmacies by early 2004. What kind of drug is memantine? Memantine is classified as an uncompetitive low-to-moderate affinity N-methyl-D-aspartate (NMDA) receptor antagonist, the first Alzheimer drug of this type approved in the United States. It appears to work by regulating the activity of glutamate, one of the brain's specialized messenger chemicals involved in information processing, storage, and retrieval. Glutamate plays an essential role in learning and memory by triggering NMDA receptors to allow a controlled amount of calcium to flow into a nerve cell, creating the chemical environment required for information storage. Excess glutamate, on the other hand, overstimulates NMDA receptors to allow too much calcium into nerve cells, leading to disruption and death of cells. Memantine may protect cells against excess glutamate by partially blocking NMDA receptors. Memantine's action differs from the mechanism of the cholinesterase inhibitors that were previously approved in the United States for treatment of Alzheimer symptoms. Cholinesterase inhibitors temporarily boost levels of acetylcholine, another messenger chemical that becomes deficient in the Alzheimer brain. What is the evidence that memantine may help Alzheimer symptoms? Forest submitted evidence in support of memantine's effectiveness in treating moderate to severe Alzheimer's disease in a new drug application to the FDA in December 2002, amended in January 2003. In September 2003, the FDA's Peripheral and Central Nervous System Drug Advisory Committee met to respond to specific questions raised by the FDA regarding application data. Briefing documents and summaries of advisory committee critiques are available on the FDA Web site at
http://www.fda.gov/ohrms/dockets/ac/cder03.htmltfPeripheralandCentralNervousSvstem
Drugs. At the conclusion of its meeting, the advisory committee
voted unanimously that the following data submitted in the new
drug application support the safety and effectiveness of memantine
in treating moderate to severe Alzheimer's disease:
(1) A 28-week U.S. study enrolling 252 individuals with moderate
to severe
Alzheimer's disease and initial scores ranging from 3 - 14 on
the Mini-
Mental State Examination (MMSE). In this double-blind study, participants
were randomly assigned to receive either 10 mg of memantine twice
a day or a placebo. Those receiving memantine showed a small but
statistically significant benefit in a test of the their ability
to perform daily activities and on the Severe Impairment Battery,
a test designed to measure cognition in profoundly incapacitated
individuals. On the Clinician Interview-Based .
Impression of Change Plus Caregiver Input, a measure of overall
function, memantine recipients also showed a benefit that was
significant in one analysis but not in another. In this study,
when participants with MMSE scores of less than 10 were considered
as a separate group, memantine recipients showed no benefit compared
to those who received placebo on either daily activities or overall
function.
(2) A 24-week U.S. study enrolling 404 individuals with moderate
to severe
Alzheimer's disease and initial MMSE scores from 5-14 who had
been taking donepezil (Aricept®) for at least six months,
with a stable dose for at least three months. In this double-blind
study, participants were randomly assigned to receive either 10
mg of memantine twice a day or a placebo in addition to their
donepezil. Those receiving memantine showed a statistically significant
benefit in performing daily activities and on the Severe Impairment
Battery, while participants taking donepezil plus placebo continued
to decline. Some advisory committee members considered memantine's
effect modest, similar in scope to the effect seen with cholinesterase
inhibitors. The advisory committee found problems with the design
of a third submitted study, conducted in Latvia, because it enrolled
individuals with vascular dementia as well as Alzheimer's disease.
An additional issue was that although the data showed a positive
effect for memantine on reducing dependence on care, the study
lacked an acceptable measure of effect on cognitive function.
According to current FDA standards, drugs approved specifically
to treat Alzheimer's disease must show a benefit on cognitive
symptoms as well as on overall function, which confirms that the
effect on cognition is clinically meaningful. In June 2003, Forest
reported preliminary results from another add-on therapy trial
enrolling participants with mild to moderate Alzheimer's who were
also taking any of three commonly prescribed cholinesterase inhibitors-donepezil
(Aricept®), galantamine (Reminyl®), or rivastigmine (Exelon®).
Data from this trial were not included in the new drug application
seeking approval of memantine for moderate to severe disease.
According to the company, the data showed that participants receiving
memantine in combination with a cholinesterase inhibitor did not
experience significantly greater
benefit in cognition or overall function than those who received a cholinesterase inhibitor and a placebo. These preliminary results suggest that memantine may not be as effective in individuals with mild to moderate Alzheimer's who are taking a cholinesterase inhibitor as it may in more severely ill individuals. This data has not yet been peer reviewed or presented in a professional forum. According to a Forest official, the company expects to report data from two additional trials of memantine in mild to moderate Alzheimer's and another trial in treating moderate to severe disease by the end of 2003. How is memantine supplied and prescribed? w.. Memantine is supplied as an oral medication in 10 mg tablets. Forest is providing prescribing information at www.namenda.com or by calling 1.877.2-NAMENDA (1.877.262.6363). Adverse effects occurring more commonly with memantine than with placebo included headache, constipation, confusion, and dizziness. Where can I get more information? The Alzheimer's Association will update this fact sheet as more information becomes available from recent clinical trials or from postmarketing experience with memantine. The latest version of this fact sheet is always available on our Web site at www.alz.org or by calling our 24/7 Contact Center at 800.272.3900. You may also call Forest directly at 800.678.1605 and ask for the Professional Affairs Division.
Medication used in Germany for 20 years
ByLauranNeergaardRuth Hobbs, 74, of Winchester, And for families
facing the
ASSOCIATED PRESSKy has been taking a combina- prospect of round-the-clock
care,
-------tion of memantine and the older maintaining even some simple
ac-
WASHINGTON - AmericansAlzheimer's drug, Aricept, for. tmties for
an extra six months is with advanced Alzheimer's dis-about a year
in a research project very important, said Zaven Kha-ease soon
can try the first treat-A year ago, Hobbs couldn't re- chatunan,
senior science adviser ment proved effective for late stag-member
Thanksgiving had even of the Alzheimer Association. i es of the
mind-robbing illness,occurred. This year, she's plan- Having another
one, that op-
Memantine should be on phar-ning to help cook, and her family
erates on a different principle, is macy shelves by January under
thecredits the combination with al- wekome news, he said brand
name Namenda, its market-lowing her to continue living The four
other Alzheimer's er says. The drug has been sold foralone , medications
- Ancept, Exelon, two decades in Germany and has___________L-
Ream^ andcognex - work by been desperately sought by many"We
had reached a point where delaying the breakdown of a bram
U.S. fanulies since word of itswe were saying,-What are we go-
chemical ca^ed acetylchohne, promisebeganspreadinglastyear.ing
to do about Mama?'" recalled which is vital for nerve cells
to .
It was approved Friday by theDeEtta Blackwell, Hobbs' daugh- communicate
In contest m^
Food and Drug Administration,ter. Now, "we're not waiting
for mantine blocks exc ^amounteof
Themarketer.ForestLaborato-the other shoe to drop." anot
.T. Tries Inc., says it has been gettingAbout 4.5 million Americans
glutamate, that can damage or hll over 1,000 calls a month from
peo-have Alzheimer's, and a million of "^l^'.inn't wt Imnw
whpth pie waiting to buy it. Others havethem are believed to suffer
severe been buying supplies overseas viasymptoms. It afflicts
mainly the el- er memantine works better when the InternetderSy,
robbing them of memory
Memantine does not offer mi-and the ability to care for them-
ers'those srucues are unaer way-raculous benefits, said the FDA,selves.
There is no known cure or ------------------ worried about giving
familiesprevention; medications only false hope.temporarily slow
the inevitable
The drug can delay worseningworsening. symptoms from Alzheimer's,
Memantine has been used in however, allowing people to Germany
for two decades to treat maintain functions such as goingdifferent
brain disorders. In 1999, to the bathroom independentlythe first
solid research was pub-for a few months longer.Ushed that suggested
memantine
It's the first option specificallycould help moderate to severe
for people with moderate to se-Alzheimer's patients; the drug
vere Alzheimer's symptoms. To-won approval for that use in other
four Alzheimer's med-rope last year. ications work only in early
stagesin U.S. studies, some patients of the disease,experienced
improvements in
Perhaps more importantly, me-memory and other skills, like mantine
works on a differentHobbs. brain chemical than the otherBut for
most, the drug instead four drugs. That means for theslowed the
pace of deterioration, first time, doctors can combineby some
measures at half the pace different Alzheimer's therapies inof
those given a dummy drug. Per-hopes of better results,formance
was measured on cogni-
Today, some families importtive tests and by tracking how well
memantine from Europe for pric-patients performed certain func-es
ranging from $147 to $240 for ations such as getting dressed or
month's supply. Forest Laborato-bathing themselves. ries, which
licensed the drug from "The effect wasn't overwheun-
Gennan maker Merz Phannaceu-[ng," cautioned FDA neurologic
ticals, refused to say whether VS.dmgs chief Dr. Russell Katz.
"But prices would fall within that they did better than they
would range, saying it had not yet decid