Pharmaceutical company Merck has announced it will end a study of its once-promising Alzheimer’s disease drug in patients with mild-to-moderate forms of the condition, just three months after Eli Lilly & Co. announced its own failure of a different drug targeting amyloid. 

This drug, called Verubecestat, targets the production of a substance in the brain called amyloid. Amyloid is widely thought to cause Alzheimer’s disease. Numerous attempts by many drug companies to block this substance in the brain have failed, repeatedly.

The results of this trial were highly anticipated, not only because of hope for people with dementia, but also because, if the drug had succeeded, it would have demonstrated that beta amyloid contributes to the cause of Alzheimer's disease, a major but recently controversial theory in the field.

This is disappointing news for families who are watching Alzheimer's rob their loved ones of their memories and emotions - it consumes and absorbs families.

There are a number of reasons that this drug may have failed and a definitive answer is still not clear. A separate trial of Verubecestat in patients who are showing only symptomatic hints of the degenerative disease will continue.

However, it is my strong view that new approaches need to be developed and new directions of research need to be supported. 

There are more than 353,800 Australians living with dementia, and the costs of managing the disease are expected to rise to $83 billion by the 2060s, representing around 11 per cent of Australia's health and residential aged care sector spending.

Importantly, this isn't the end for beta amyloid theory, just yet. There's a trial of another important drug for Alzheimer's, Aducanumab, being run by Biogen - another pharmaceutical company - which has shown interesting and encouraging signs.

And there are numerous other trials in the pipeline of drugs which act in a variety of different ways to try to slow or reverse Alzheimer’s. I believe that there must be much more effort in this area.

We must continue to pursue this disease. There's good reason to have hope and optimism that with the pursuit of excellent science and some rethinking about this disease, a treatment will become available for this devastating disease in our lifetimes.