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Alzheimer's Disease Clinical Trials: The History of Medical Breakthroughs

Clinical trials are research studies that expose volunteer participants (or groups of people) to one or more health-related intervention.  The goal of clinical trials is to evaluate the safety, effectiveness, and outcomes of drugs, medical devices or biologic (a vaccine, blood product or gene therapy).

If clinical trials had never existed, medication to kill pain, destroy bacterial infections, treat disease (like rheumatoid arthritis), or those that slow the progression of Alzheimer’s disease (AD), would likely not be available today.  To take it a step further, vaccinations for contagious outbreaks such as polio, innovative lifesaving procedures like blood transfusions, or even antiseptic surgical methods may not exist, because all were dependent on clinical trials to prove safety and efficacy before the public launch the new drug, device, vaccine, treatment, or intervention.

Clinical Trials and Alzheimer’s Disease

Many organizations such as the National Institute on Aging, have supported clinical research trials to compare normal age-related aging of the brain to that of Alzheimer’s disease (AD).  Scientists and medical professionals work together to understand the many factors related to AD, including genetic, biologic, and environmental factors.  Newer and better methods of early diagnosis have been discovered as a direct result of clinical trials.  Innovative methods, of slowing down symptoms and treating the progression of AD, have been identified and found to be safe and effective as a result of multiple clinical study tests.

Today, there are over 90 different drugs undergoing evaluation in clinical trials for the safe and effective treatment of Alzheimer’s disease, and more are in the pipeline awaiting approval for human testing by the Food and Drug Administration (FDA).  Clinical trials have brought the medical profession closer than ever before to the discovery of a safe and effective treatment and prevention measures to overcome the devastating effects of Alzheimer’s, on people with AD, their family members, and the community at large.

The History of Clinical Trials: The End of Poliomyelitis

When looking at historic medical breakthroughs resulting from clinical trials, one of the most impactful events was the launch of the vaccine developed by Jonas Salk that prevented poliomyelitis (commonly referred to as polio). 

Polio is a viral disease that affects the nervous system.  The virus can invade the spinal cord and brain, resulting in partial or full paralysis and difficulty breathing.  Thus, the infamous iron lung became known as an iconic lifesaving treatment modality for polio.  The peak of the polio outbreak was in the early 1950’s—about the same time the breakthrough polio vaccine was being tested in clinical trials.

It is estimated that between 1937 and 1997 more than 457,000 people in the U.S., and hundreds of thousands more world-wide, suffered from some form of polio. Thousands were paralyzed in the U.S. alone.

To get a glimpse of the magnitude of the polio vaccine discovery and how it affected the country, one must go back to the early 50’s when thousands of Americans were stricken with the viral infection.  Iconic visuals of the polio era featured children on crutches and images of the iron lung. Parents were literally panic-stricken at the thought of their children contracting the disease.  Rumors abound with all sorts of myths about how the disease was spread.  Kids were prohibited from swimming, going to movies, and people everywhere were nervous about getting too close to strangers. A handshake was even thought by many to be the culprit when it came to people’s beliefs about the mode of transmission of the disease.  When considering the history of vaccinations, “the polio vaccine is one that people think of because it had such an impact,” said Dr. Jeffrey Baker, director of the history of medicine program at the Duke University School of Medicine.

The introduction of the polio vaccine in 1955 was perhaps one of the biggest medical advances in U.S. History.  It resulted in an era that was considered the height of America’s faith in clinical research and science.  On April 12th, 1955, as the polio vaccine availability announcement was made, people literally ran into the streets crying.  Jonas Salk was invited to the White House, where President Eisenhower choked up while thanking him for saving the world’s children from the atrocities of the disease. Within two years of the 1955 announcement, U.S. Polio cases dropped by an astounding 85 to 90 percent.

History of Clinical Trials and Medical Breakthroughs

New types of life-enhancing and lifesaving therapies are possible today due to clinical trials that systematically tested the outcome of innovative scientific discoveries.  The history of medical breakthroughs offers a glimpse of just how instrumental the clinical studies were in providing vital information required for medical breakthroughs over the course of time.

The Discovery Treatment for Vitamin C Deficiency

In the mid 1700’s, one of the first ever controlled clinical trials, conducted by Dr. James Lind, resulted in the discovery that citrus fruit could prevent scurvy (a disease caused by a deficiency of vitamin C in the diet).  This trailblazing discovery helped to illustrate the impact that clinical studies could have on the public’s general health and wellbeing.

Hypothermia Before Surgery

In the year 1757 clinical trials were conducted to observe the result of prolonged exposure to the cold. The Swedish Academy of Sciences released a report showcasing how people could survive longer when exposed to prolonged cold temperatures.  In 1798, Dr. James Currie conducted a clinical trial with volunteers who were asked to take long baths in cold water.  He observed that the study particpants had a reduced heart rate when submerged in cold water.  This discovery led to modern day surgical practice of reducing the heart rate to slow down the heart’s need for oxygen during surgery. 


Tuberculosis (TB) was a common cause of death over a century ago.  In fact, in 1907 there were over 110,000 cases of TB in Britain.  In 1943 microbiologist, Selman Waksman at Rutgers University in New Jersey, discovered that streptomycin cured animals stricken with TB, without any evidence of harmful side effects.  The idea of randomization was introduced in 1923. However, the first randomized control trial of streptomycin (to treat pulmonary tuberculosis) was carried out in 1946 in the UK.  Thus, streptomycin became the first effective treatment for TB, saving literally millions of lives.

Modern Day Breakthroughs in Medicine

Randomized Controlled Trials

Perhaps one of the most impactful discoveries in clinical trials was the implementation of “randomized controlled trials.”  This is what many medical professionals refer to as the “gold standard of medical research,” because it has given scientists a tool to more accurately measure which treatment works best.

Randomized clinical trials involve dividing study participants into 2 groups.  One group receives the medicine or treatment being evaluated, while the other group receives a placebo (in the case of drug trials).  Evaluation of the outcome, by comparing the two groups with each other, has led to the beginning of the evidence-based medicine era that continues to this day.  This methods has helped scientists in effective dicovery of the efficacy and safety of new treatment modalities.


The American Diabetes Association reports that if the current trends continue, 1 in 3 adults in the United States may likely develop type 2 diabetes by the year 2050.  Insulin was discovered as the first treatment, for what otherwise would have been a lethal disease for millions. Clinical investigators still strive today to develop new drugs, better monitoring devices, and to hopefully find a cure for diabetes.   

New Drugs for HIV

A new vaccine is being tested in South Africa to stop the HIV pandemic.  Breakthrough drugs such as PrEP (pre-exposure prophylactic) which have been found in clinical trials to effectively prevent HIV, are evidence of just how important clinical research trials are to the world of medical advancement.

The Future
Future breakthroughs such as stem cell therapy to treat motor neuron diseases in those with spinal cord injuries, fetal stem cell injections to treat strokes, and many other exciting treatment modalities are on the horizon. Most of these innovative new treatment modalities would never be possible without the help of medical science via clinical research trials.

The Future of Alzheimer’s Prevention

The future of Alzheimer&rs’s treatment and prevention research is only possible if volunteers step up to the plate to get involved in clinical trials and studies. Today, approximately 70,000 people are needed to participate in over 150 clinical trials for Alzheimer’s disease in the United States alone.  Whether you are a person with AD or MCI, you have a family history of AD, or you are a healthy adult, you can help scientists learn more about the treatment and prevention of Alzheimer’s disease.  Learn more about clinical trials for AD by CLICKING HERE.

To learn more about AD, check out our free courses on AD caregiving and AD prevention & treatment. 

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