A recent article in The Washington Post detailed mounting pressure on the FDA to loosen restrictions on off-label drug uses. A drug may be approved for one disease, but have benefits for treating another. In such cases, doctors may prescribe the drug off-label, or for something other than its approved use.
Drug makers can't legally promote off-label uses for drugs, and most insurance companies don't cover off-label prescriptions. Despite these barriers, off-label prescribing is fairly common. The article mentions reports showing that 30% of cancer drugs and 70% of pediatric antipsychotic drugs are used off-label.
For Alzheimer's patients, there are only five FDA-approved drugs. And these drugs only provide symptomatic benefits for some patients. None slow the progress of the disease. But a growing body of research suggests that some drugs approved for other diseases, such as diabetes and hypertension, may be beneficial for Alzheimer's patients.
These drugs could be prescribed off-label but the expense would put them out of reach for many. And some drugs may not be safe for elderly patients or those with dementia, as most were never tested in these patient populations. For instance, antipsychotic drugs are often prescribed off-label for behavioral symptoms associated with dementia, despite the fact they are associated with other health risks and provide only modest benefits [1].
The answer is to conduct clinical trials of these approved drugs so they can be FDA approved for Alzheimer's. The Alzheimer's Drug Discovery Foundation (ADDF) is supporting 15 such trials, which are referred to as "repurposing" trials as the drug is being repurposed for a new use.
One promising repurposing trial we are funding is of the diabetes drug liraglutide. People with diabetes have up to a 73 percent higher risk of dementia and a 100 percent higher risk of developing vascular dementia. In addition, the brain cells of people with dementia can have trouble using glucose for energy. A small pilot study showed that a 26-week treatment with liraglutide in Alzheimer's patients may prevent a decline in the brain's ability to use glucose [2]. In addition, a number of preclinical studies suggest that liraglutide may reduce beta-amyloid plaques, decrease inflammation, and slow cognitive decline. We are now funding a larger study of liraglutide in Alzheimer's patients by Dr. Paul Edison at the Imperial College in London.
Hypertension in middle age is another risk factor for Alzheimer's disease, and certain classes of anti-hypertension drugs, such as angiotensin II receptor blockers (ARBs) may reduce the future risk of Alzheimer's disease more than other classes [3]. The ADDF is supporting a study by Dr. Ihab Hajjar from Emory University of candesartan, an ARB, in early-stage Alzheimer's patients without hypertension. In addition, we are also funding a trial by Dr. Sandra Black from Sunnybrook Research Institute comparing two classes of hypertension drugs, ARBs and angiotensin converting enzyme (ACE) inhibitors, to see if one is more beneficial for Alzheimer's patients.
To limit the risks and expense of off label prescribing, the FDA could ease the approval requirements for repurposed drugs. This could mean new, beneficial drugs for Alzheimer's patients in as little as a few years. Until then, the ADDF will continue to fund repurposing trials and advance these potentially life-saving treatments as quickly as we can.
To find out more about ADDF and the drug research we are funding, visit alzdiscovery.org.
Nick McKeehan is a member of the ADDF's Aging and Alzheimer's Prevention program. He evaluates the scientific evidence for and against therapies to promote brain health and/or prevent Alzheimer's disease at our website CognitiveVitality.org and contributes regularly to the site's blog. Mr. McKeehan previously served as Chief Intern at Mid Atlantic Bio Angels (MABA) and was a research technician at Albert Einstein College of Medicine investigating repair capabilities of the brain. Mr. McKeehan received a bachelor of science degree in biology from Purdue University, where he was awarded a Howard Hughes Scholarship. He also writes about the biotechnology industry for 1st Pitch Life Science.
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