The patch, being jointly developed by >Ono Pharmaceutical and the Japanese unit of >Novartis, is currently in phase II clinical trials in Japan, where the companies hope to bring it to market as soon as possible.
The drug is already sold as Exelon (rivastigmine), in capsule or liquid form, in more than 70 countries worldwide.
However, the patch will offer a novel drug delivery alternative for elderly dementia patients who do not take their medication because they either have difficulty swallowing or are non-cooperative in taking their medication.
Alzheimer's disease, an incurable and fatal brain disease, is the most common type of dementia in developed Western countries, affecting approximately 20 million people worldwide. This figure is expected to increase 3-4 fold in the next 50 years.
It starts out with mild memory loss (cognitive decline) but progresses to damage the brain severely, causing confusion and eventually leaves the patient unable to care for themself.
The class of drugs most commonly used to treat and prolong the symptoms of AD is called acetylcholinesterase inhibitors (AchI). This market has been dominated by >Pfizer's Aricept (donepezil), which holds over 50 per cent of the global market. Novartis's Exelon and >Ortho-McNeil's Razadyne/Reminyl (galantamine) share the remainder.
Novartis will use the new patch to increase its share of the AD market and continue to compete with its biggest rival, Pfizer, who last year launched a new version of Aricept that dissolves in the mouth, also designed to make administration easier for AD patients who have difficulty swallowing.
The worldwide Alzheimer's disease therapeutics market is estimated to grow 11 per cent each year from $1.79 billion in 2004 to approximately $3.05 billion in 2009 and during this time AchIs will continue to dominate the market.
However, beyond this, their sales will suffer because of the expiry of their patents and the launch of new and combination products, such as the NMDA receptor antagonist recently launched by Forest's Namenda, and the availability of cutting edge disease-modifying therapies.
Alternative drug delivery technologies are increasingly being used by drug companies to survive in tough markets such as this. A relatively emerging market, transdermal delivery is now worth $12.7 billion and is expected to increase to $21.5 billion in the year 2010 and $31.5 billion in the year 2015.
If this drug patch can improve patients taking their medication, it has the potential to play a part in also improving the quality of life of patients and their caregivers and could lead to significant cost savings to society.
It is important for patients to regularly take their AchI medication, as studies suggest that continual treatment can slow cognitive decline, reduce the amount of caregiver time a patient may need, and can increase the time until a patient needs to be institutionalised.
The annual total costs in the EU for AD have been estimated to be between €64 and €149 billion, and further estimates reveal that as much as €1,660 per patient could be saved for each month that institutionalisation is delayed, according to a report in the British Medical Journal, 2003.