The sooner the better?

FDA recommends investigating early-stage treatment of Alzheimer's disease

Julia Korowski, XX2 century

The US Food and Drug Administration (FDA) has presented a draft of a new guideline for the development of drugs for Alzheimer's disease (AD). In it, the agency focuses on the treatment of AD in the early stages. Now people who do not yet have noticeable signs of the disease can participate in clinical trials – only the appropriate biomarkers. A drug for such a group of "early" patients can be considered effective if it can affect these biomarkers. So far, the agency has submitted only a draft version of the document, which will enter into force no earlier than three months after doctors and patients express their opinion.

Treating and curing Alzheimer's disease is a medical dream. They are trying to at least slow down the development of the disease, but they are still failing here. Clinical trials are failing one after another – the other day Merck & Co., Inc. announced another such defeat. The further we go, the more scientists talk about treatment in the early stages.

The new FDA guidelines pay a lot of attention to "early" therapy. In this document, participants in clinical trials are divided into four groups:

• patients with severe dementia;
• patients with moderate asthma, when functional disorders are already noticeable, but it is not yet possible to diagnose dementia;
• people who have pathophysiological changes characteristic of AD and impaired cognitive functions, but no functional disorders;
• patients who do not have symptoms of AD yet, but the corresponding biomarkers are present.

Thus, people who have the disease at the earliest stage can participate in the research, and biomarkers are considered sufficient grounds for this. Moreover, changes in these biomarkers can also serve as an indicator of the effectiveness of the drug. In 2013, when the FDA prepared the previous draft guidelines, biomarkers were assigned a more modest role. At that time, experts were not sure that changes in biomarkers would actually eventually lead to an improvement in the patient's condition. Doubts remain even now, so the FDA recommends conducting long–term trials so that it is possible to assess the condition of patients by other parameters - for example, to notice the appearance or absence of cognitive impairment.

In the case of patients who suffer only from cognitive disorders, medications that improve cognitive abilities can be considered effective. But in the treatment of more severe patients, it is necessary not only to improve memory, etc., but also to combat functional disorders, the FDA notes. The Agency stipulates that each case will be considered separately and in practice the evidence of effectiveness may be inconclusive. For example, the correct execution of a single test is unlikely to force specialists to approve the drug.

In addition, the FDA is ready to reconsider its views as medicine develops. If biomarkers cannot yet predict the outcome and course of the disease for sure, it is likely that this will become possible in the future.

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