Study says Alzheimer's drugs do not delay onset

Researchers at the Italian National Centre for Epidemiology, Surveillance and Health Promotion have said that prescribing Alzheimer's disease (AD) drugs to patients with early memory problems does not delay disease onset.

The research, which was published in the online journal PLoS Medicine, assessed the three main AD drugs, Eisai's Aricept (donepezil), Novartis' Exelon (rivastigmine) and J&J's Reminyl (galantamine) currently approved for use in mild-to-moderate AD and prescribed off-label for pre-dementia symptoms.

The researchers found that none of the drugs examined in six clinical trials significantly reduced the rate of progression from mild cognitive impairment (MCI) to full dementia. They concluded that accurate assessment of the effect of anti-cholinesterase medicines was confused by the lack of a precise definition for MCI. The findings may now persuade doctors who prescribe anti-cholinesterase treatments off-label in MCI to hold off doing so.

Medical opinion is currently divided over the effectiveness of existing AD drugs in MCI, which has lead to differing rates of use and high-profile arguments over patient access to treatment. For example, in September 2007 Eisai took the UK's National Institute for Health and Clinical Excellence (NICE) to court over a dispute on the cost-effectiveness of Aricept. Eisai claimed the agency's cost-effectiveness calculations were flawed but the court backed the restrictions.

Dr Roberto Raschetti, who headed up the Italian research team, said that in Italy an estimated 27 per cent of patients diagnosed with MCI are given AD drugs off-label and said it was likely the situation was similar in other countries. He argued more clinical trials were needed, using a single agreed definition of MCI, before there could be any justification for doctors to use the drugs in pre-dementia cases, especially as the drugs can have harmful side effects.

In October 2007, a Canadian study suggested that cholinesterase inhibitors used to treat AD might often be prescribed for too long, exposing patients to unpleasant side effects for no reason and burdening healthcare systems with extended costs.