On Monday, China announced that a new drug, meant to potentially treat Alzheimer’s disease, will be available to Chinese patients by the end of this year.
What is Alzheimer’s
Alzheimer’s disease is a progressive brain disorder that typically affects people older than 65. When it affects younger individuals, it is considered early onset. The disease destroys brain cells and nerves, and disrupts the message-carrying neurotransmitters. Eventually, a person with Alzheimer’s loses the ability to perform day-to-day activities.
Symptoms include memory loss, difficulty in completing familiar tasks, confusion with time or place, problems in speaking and writing, decreased or poor judgment, and changes in mood and personality. Alzheimer’s disease is also the most common cause of dementia — which is a syndrome and not a disease in itself, and whose symptoms include loss of memory, thinking skills, problems with language, changes in mood and deterioration in behaviour.
Hunt for a cure
There is no cure for Alzheimer’s, because its exact causes are not known. Most drugs being developed try to slow down or stop the progression of the disease.
In the US, there exist five prescription medications approved by the Food and Drug Administration (FDA) to treat the symptoms of Alzheimer’s. Last month, US-based biotechnology firm Biogen sought FDA approval for “aducanumab”, a drug it claimed could slow down the clinical decline in patients in the early stages of Alzheimer’s.
The Chinese drug
China’s National Medical Products Administration (NMPA) announced the decision in a statement. Called GV-971 or “Oligomannate”, it is a seaweed-based drug, administered orally. It has been jointly developed by the Shanghai Institute of Materia Medica and the Ocean University of China and Green Valley Pharmaceutical Company Ltd. A statement by Green Valley said oligomannate has received approval from NMPA, making it the “new drug for the treatment of ‘mild to moderate Alzheimer’s disease (AD) and improving cognitive function’.”
Chinese researchers have claimed oligomannate is capable of treating mild to moderate Alzheimer’s and may improve cognition. Phase three of clinical trials involved 818 patients, and the drug was “proven to continuously and effectively improve cognition among mild-to-moderate Alzheimer’s disease sufferers over a period of nine months”. A multi-centre global phase 3 clinical trial, with sites in the US, Europe and Asia, might be initiated in early 2020.
How treatments usually work
There is a degree of consensus in the scientific community that Alzheimer’s involves two proteins, called beta amyloids and tau. When levels of either protein reach abnormal levels in the brain, it leads to the formation of plaque, which gets deposited between neurons, damaging and disrupting nerve cells. But it is not known why the levels of these proteins reach abnormal levels in the first place.
Most existing drugs for Alzheimer’s try to target these proteins to manage some of the symptoms of Alzheimer’s. Aducanumab works by targeting the protein beta amyloid.
What’s different in new drug
Green Valley claims that oligomannate has a different mechanism of action from that of other drugs. A preclinical study of oligomannate published in the journal Cell Research in September describes the effects of sodium oligomannate on the progression of the disease in a mouse model. This study builds on evidence that suggests an association between microbiomes in the gut and progression of Alzheimer’s. The study suggests that it is possible for a microbiome imbalance in an individual’s gut to influence the formation of plaque and inflammation of the nervous tissue. It suggests Alzheimer’s is not driven by proteins alone, but its development may require the interaction between the gut, brain and other inflammatory factors. Even so, the study did not establish if the link between gut bacteria and neuroinflammation in Alzheimer’s is direct or indirect.
Geng Meiyu, professor at CAS and lead inventor of the drug, has been quoted as saying that oligomannate works by reconditioning the imbalance of the microbiomes in the gut, thereby reducing the deposition of plaque and improving cognitive function.
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