Eisai and Pfizer are calling for “clear and consistent clinical guidelines” in the diagnosis and treatment of Alzheimer’s disease following release of a physician survey at the International Conference on Alzheimer’s Disease and Related Disorders showing many doctors are likely to abandon treatment before it has a chance to work.

The survey, largely comprised of neurologists, found that only one in 8 waits six months to decide if a drug treatment is working although a new study, AWARE, shows around one third of patients receiving Aricept take longer than 24 weeks before a measurable improvement in their condition is apparent on cognitive scores.

The survey of 376 physicians from over 40 countries shows the vast majority (73%) evaluate treatment response within three months and indicates that around a third of them would try a different medication at that stage if symptoms decline or are merely stablised. Over half of them rely on cognitive assessments rather than improvements in ability to carry out daily living activities or behavioural aspects such as aggressive outbursts or wandering.

AWARE, published recently in the journal CNS Drugs (2006;20 (4):311-325), shows some patients are slow to demonstrate a treatment response. Almost a third (31%) of patients with mild to moderate disease receiving Aricept for 24 weeks demonstrated uncertain benefit initially. They were then randomised in a double-blind phase to receive either a further 12 weeks Aricept treatment or placebo. Those receiving further Aricept showed a significant improvement in cognition and behaviour and a trend to improvement on assessment of functional improvement in activities of daily living.

Three quarters treated with Aricept showed improvement or stabilisation across cognition, function and behaviour.

Dr Bengt Winblad of the Karolinska Institute, Stockholm commented: “Stabilisation of symptoms or a slowing of decline should be considered as treatment benefits. It’s important for physicians to take this into account when carrying out initial treatment evaluations.”

Not showing improvement on the MMSE did not mean that improvement was not evident in other domains but these areas, of huge importance to carers and patients themselves, tend to be overlooked, he added.

“My feeling is that Aricept works in almost all patients. The problem is that in some people you can’t see the benefit until you withdraw treatment and the patient then gets worse.”

Speaking at a meeting to publicise the survey results, Professor Howard Feldman of University of British Columbia predicted that within five years disease-modifying treatments for AD would be available.

Of these, the first could be Myriad Genetics R-flurbiprofen (MPC-7869) which is currently in Phase III trials. Although a Phase II study showed no benefit overall, patients with mild disease receiving the highest dose did see improvement.

AD is increasing exponentially, Dr Feldman said. In the US prevalence among the over 65s is doubling every five years. Over the next 20 years there will be a doubling of cases worldwide with more than 81 million people having the disease by 2040.

“If we could delay the onset of AD by five years, we could halve the prevalence at 2040” he claimed. AD is costly, he added, with an estimated $100 billion figure for managing the disease in the US. Not controlling AD early had other cost implications as patients forget to take medications for co-morbid illnesses such as diabetes and hypertension and develop preventable complications.

From Olwen Glynn Owen in Madrid