The more drugs we trial, the closer we get

We must declare a war on Alzheimer’s disease, explains Bill Ketelbey

Some of the biggest threats to human survival in previous generations were infectious diseases like influenza, smallpox and tuberculosis. With the advent of antibiotics and vaccines to eradicate or control these diseases, the average life expectancy today, at about 85, is almost 20 years longer than in our grandparents’ day.

Similarly, our understanding of risk factors for cancer, stroke and heart disease, and improvements in their diagnosis and treatment, mean they are not the killers they once were. In many countries death rates for the big three — heart attack, stroke and cancer — are declining. Between 2000 and 2014, deaths in the US resulting from stroke, heart disease, and prostate cancer decreased 21 per cent, 14 per cent and 9 per cent, respectively. The one disease bucking this trend is Alzheimer’s disease. Death from Alzheimer’s in this same period increased 90 per cent.

Current estimates are that 50 million people worldwide are affected by Alzheimer’s. It is the second leading cause of death in Australian men after heart disease, but recently became the leading cause of death in women. There are around 90,000 new cases of dementia recorded in Australia every year. By 2056, it will be 240,000 each year, at a cost of almost $30 billion.

When you project these kinds of numbers onto much larger economies, like the US and China, the impact of Alzheimer’s will be staggering. By 2056, the number of people affected by Alzheimer’s disease in Tasmania will be over 21,000 — enough to fill the Blundstone Arena to capacity, plus a couple of thousand more in the car park — with an estimated cost of $449 million. That’s a very big dent in the Tasmanian health budget to spend on a single disease, and a huge burden on Tasmanian aged care organisations already in crisis.

The number of people affected by Alzheimer’s disease doubles every 20 years and threatens to bankrupt health systems around the world. Unfortunately, the treatments available today for Alzheimer’s can’t prevent that from happening.

Unlike heart disease, cancer and stroke, for which there are many effective treatment options, there are only four drugs available to treat Alzheimer’s and none of them slows the progression of the disease. In the last 30 years, hundreds of research drug candidates have been trialled and failed. The biggest problem is that we don’t fully understand what causes the disease. The brain changes in Alzheimer’s begin up to 15 years before the symptoms appear, so drugs aimed at improving the symptoms of Alzheimer’s are likely to be too late to slow the disease’s progression.

We need to understand the enormity of the problem we are facing, and to ensure that healthcare providers, politicians and policy makers are equally aware.

We need a global “war on Alzheimer’s”, like the successful strategies mounted against infectious diseases, cardiovascular disease and cancer. Economic modelling has shown that even a 5 per cent reduction in the number of people with dementia will have a significant impact on reducing health costs, on top of the benefit against human suffering.

We need increased investment in Alzheimer’s treatment and prevention. The need to find effective therapies to treat, and ultimately prevent, Alzheimer’s has never been more urgent. The path to a successful treatment is littered with failed research drugs, yet each failure provides vital knowledge and helps sharpen our research focus. The more research drugs we discover and trial, the more targeted shots on goal we have and the quicker we will succeed in managing this awful disease.