Which is to become the savior of Alzheimer’s disease?

Alzheimer’s disease (AD), commonly known as senile dementia, is a degenerative central nervous system (CNS) disease that has an insidious onset, with the clinical symptom mainly of neuropsychiatric symptoms, manifesting as progressive memory impairment, cognitive impairment, personality change and language disorder, etc.

The incidence of AD is age-related, is 2%-4% in the whole populations, and is 5% especially for the middle-aged and elderly aged above 65; the incidence grows by several times with age: the incidence may increase to 25% for the elderly aged above 85 and the incidence is up to 60% for the elderly aged above 95, according to the analysis.

In accordance with the World Alzheimer Report 2015, there were about 46.80 million AD patients worldwide, and this number will almost double every 20 years, to reach 74.70 million in 2030 and over 130 million in 2050.

China has gradually entered the aging society. According to statistics, the AD patients in China are nearly 10 million, with over 300 thousand new cases increased every year, and the AD incidence to continue to increase in the future. There is still no effective cure for such a huge patient population even nowadays with developed science and technology.

AD is like an eraser in the brain which cruelly erases AD patients’ memories bit by bit in the days when they are battling against the disease, and is called a "21^st century plague".

Market size of existing drugs

There is still no panacea for curing AD. The drugs clinically used today mainly alleviate the cognitive impairment and mental disorder, etc., and include cholinesterase inhibitor, excitatory amino acid receptor antagonist, TCM intervention, cerebral metabolic activator, drug affecting free radical metabolism, vasodilator drug, statins, antipsychotic drug, antidepressant, antianxiety drug and sedative-hypnotic drug, etc.

Analysis of overseas market

The sales data of the main AD drugs including donepezil, galanthamine, rivastigmine and memantine in recent years are as shown in the following figure.

Developed by Eisai, and approved by FDA to be marketed in the U.S. in November 1996, donepezil is currently the only drug that can treat mild, moderate and severe AD, and is also an old drug that has the best safety and tolerability among the commonly used drugs. It reached the sales peak of USD 3.99 billion in 2009, and can be called a mega-blockbuster drug in the AD therapeutic field; but its market has gradually shrunk since 2010 with patent expiration, which is seized by the rivastigmine and memantine marketed after it.

Developed by Novartis, and approved by FDA to be marketed in the U.S. in April 2000, rivastigmine is the first drug approved to treat the mild to moderate AD associated with Parkinson's disease, and is safest for patients requiring multiple drug combinations. It became a blockbuster drug in 2010 with sales exceeding USD 1 billion, and became a super-blockbuster in 2013 with sales growing to USD 2 billion, but its sales have declined since 2013, possibly affected by its patent expiration in 2012.

Developed by J & J, and approved by FDA to be marketed in the U.S. in February 2001, galanthamine mainly targets mild to moderate AD patients with sleep disorder. Its sales reached USD 457 million in 2009, but its market performance has not been good thereafter, and is currently maintained at about USD 150 million.

Developed by FOREST LABS, and approved by FDA to be marketed in the U.S. in October 2003, memantine, unlike the mechanism of action of the above three drugs (which are all acetylcholinesterase inhibitor), is the first and only N-methyl-D-aspartate (NMDA) receptor antagonist approved by FDA, of which the clinical trial has proved its safety and tolerability to be better than AChEI. It became a super-blockbuster drug in 2011 with sales reaching USD 2 billion, and it is currently the AD drug with the best sales in the market.

The overall AD market has shrunk and continued to fall in the world in recent years, which is in urgent need of revolutionary new drugs in the future.

Analysis of the Chinese market

According to the sales statistics of Chinese sample hospitals, the dementia drug market in China has been keeping the continued growth trend, with the overall market of RMB 2.878 billion in 2016, growing by 10.4% year on year, and accounting for 19% of nervous system drugs. See the following table for the sales data of TOP10 in such kind of drugs. The mainly anti-AD drugs therein are oxiracetam, vinpocetine, citicoline, donepezil, and cerebroprotein hydrolysate, etc.

Developed by ISF S.p.a., oxiracetam product is currently not imported to China. As an analogue of piracetam, oxiracetam has higher pharmacological activity, more significant clinical efficacy and less adverse reaction, therefore, it leads in the Chinese AD market, and almost accounts for a half of the entire dementia drug market in China. Its market is currently mainly occupied by CSPC Pharmaceutical Group (38.7%), Harbin Medisan Pharmaceutical (22.5%) and Guangdong Sencee Pharmaceutical (29.2%).

Developed by Gedeon Richter, vinpocetine products have been imported to China. The growth of vinpocetine has been strong in recent years, with the Chinese product from Henan Runhong Pharmaceutical accounting for about 70% market, and imported products accounting for 21%, showing a high market concentration.

Other relevant drugs that have good market performance include citicoline, donepezil and cerebroprotein hydrolysate, etc. The overall dementia drug market has been keeping continued growth in recent years in China, however, the growth has slowed down much, and the market is in urgent need of fresh blood.

Sales data of TOP10 dementia drugs in China in 2011-2016

Data source: PDB (the actual sales data shall be amplified for about 4-5 times)

Resilient R&D battlefield

Most drugs in the AD field cure the symptoms not the disease, without significant efficiency, and can only control or improve the cognitive and functional symptoms within a short time, instead of fundamentally preventing or significantly delaying progress of the disease. Each pharmaceutical giant has joined AD R&D one after another driven by the great market prospect. As the AD field has been a difficulty for the new drug R&D, the clinical research has suffered defeat after defeat over the decade, which is a significant blow to the R&D investors.

Several AD drugs failed in recent years

Many pharmaceutical companies have not given up AD R&D though there are many difficulties, and they advance wave upon wave and demonstrate resilience. It is hoped that there will soon be the savior of AD in the future AD battlefield.

Some AD drugs in clinical trial Phase III in the world

Source: Pharmacodia.com Author: Wanxi