麻豆传媒

The first large trial of a promising Alzheimer鈥檚 drug provides convincing evidence that it slows the impact of the devastating disease.

Memantine is the first Alzheimer鈥檚 drug designed to tackle the late stages of the neurodegenerative illness and works on a different system in the brain to other existing drugs.

Barry Reisberg, a psychiatrist at the New York School of Medicine, and colleagues saw marked improvements during the six months for which patients were given memantine.

鈥淭he drug seems to be slowing the progressive loss of basic capacities [like bathing and dressing] by at least half,鈥� Reisberg told 麻豆传媒. 鈥淚t looks like this drug really will have an impact on this disease.鈥� There are no other treatments for the advanced stage of the disease.

Richard Harvey, director of research at the Alzheimer鈥檚 Society, a UK charity, says: 鈥淭his is a very important contribution. It鈥檚 really the first large, well-designed and published study of memantine.鈥�

The study, published in the New England Journal of Medicine was part-funded by memantine鈥檚 creators, Merz Pharmaceuticals. Merz submitted the study findings the European Agency for the Evaluation of Medicinal Products, and these were key in the 2002 decision to approve the new drug for use in Europe. The US Food and Drug Administration is currently reviewing the drug.

Slowed decline

Reisberg and colleagues gave the memantine to 181 patients with moderate or severe Alzheimer鈥檚 disease at 32 medical centres across the US. All the patients lived in the community and had trouble dressing, bathing and going to the toilet.

The decline in the ability to carry out these functions was slowed markedly in patients given the drug, compared with those on placebo. Patients on memantine showed a similar resilience in the decline of their mental status 鈥� or cognitive ability.

The drug works by blocking a brain messenger chemical called glutamate. An abundance of this molecule can lead nerves in the brain to become over-stimulated, resulting in damaged or death. This 鈥渆xcitotoxicity鈥� has been linked to the death of neurons in the brains of Alzheimer鈥檚 patients, says Reisberg.

Neurons that respond to glutamate are involved in memory and learning. No other Alzheimer鈥檚 drugs focus on this brain circuitry. Other drugs act by strengthening the activity of neurons that use the neurotransmitter acetylcholine to transmit their signals.

Harvey, told 麻豆传媒 that memantine is potentially also the first 鈥渄isease-modifying鈥� drug, with the potential to protect the brain from further damage. Alzheimer鈥檚 disease affects at least 15 million people globally and this number is set to increase rapidly as the world鈥檚 population ages.

Journal reference: New England Journal of Medicine (vol 348, p 1334)