Clinical trials are a large part of medicine. They are research studies done with individuals who have consented to be part of the trial, and researchers evaluate whether a medical, surgical, or behavioral intervention is safe and effective.1 Trials are often done to see if a new prospective treatment is more effective or has less harmful side effects than the current standard treatment.1 They can also be done to evaluate new ways of diagnosing or preventing a disease.
When people participate in a clinical trial, there is always the chance that it will fail, and in some cases, end early. This has happened regularly with clinical trials related to Alzheimer’s disease, and most recently with two clinical trials in March 2019. Several trials of treatments aimed at amyloid-beta, a toxic protein, failed, and two large clinical trials looking at an amyloid drug called aducanumab were discontinued.2 This drug seemed to be effective in removing amyloid-beta from the brain, and early studies showed the possibility of it slowing the progression of dementia.2 Despite the disheartening news about the clinical trials, there is still new research being done for Alzheimer’s disease, and new clinical trials are on the horizon.
What does or doesn’t work?
Failed trials and dead ends, frustrating and saddening as they can be, are a part of medicine. Doctors need to find out what works, and that includes finding out what doesn’t work, as well. Thankfully, there are always researchers and clinicians working to find new treatments, screening tools, medications, and ways to help prevent diseases. Even with setbacks, there is still important research being done for the future.
Sometimes a drug that’s evaluated in a clinical trial for one disease isn’t effective for that disease – but could be effective for another disease. There was a clinical trial for a possible cancer drug called bryostatin-1, which was not effective for cancer, but did activate PKC-epsilon.2 Creating new connections between brain cells, or encouraging communication across synapses in the brain, can help reverse or slow down the loss of cognitive function seen in Alzheimer’s disease, and in mice with a similar condition to Alzheimer’s, these connections were made by a protein called PKC-epsilon. Bryostatin-1 has been found to reverse synaptic loss and encourage synaptic maturation in animals with neurological conditions, including Alzheimer’s disease.3
Several clinical trials of bryostatin-1 have already been done, with results that included the return of major functions in patients with advanced Alzheimer’s disease, including swallowing, vocalization, and word recognition.3 This is encouraging for additional clinical trials looking at this potential treatment.
Another emerging area of research is looking at personalized cognitive diagnostics of those genetically at-risk for developing Alzheimer’s disease. Spatial navigation has been emerging as an important factor in identifying preclinical Alzheimer’s disease.4 Preclinical Alzheimer’s disease has been associated with deficits in wayfinding strategies, but not route learning strategies – however, early-stage symptomatic Alzheimer’s disease often presents with deficits in both wayfinding and route learning strategies.5 Spatial navigation and wayfinding strategies, then, can be an early clue to potential Alzheimer’s disease. A new study using the Sea Hero Quest app has found that assessing navigational behavior with that app effectively discriminated between normal, healthy aging and genetically at-risk individuals for Alzheimer’s disease.4 If scientists can identify preclinical factors, this can lead to earlier treatments and interventions, and potentially lead to treatments that can slow or stop the cognitive decline.
Although some studies for Alzheimer’s disease treatment have failed, there are plenty of other clinical trials, studies, and research being done presently. New interventions and treatments are continuing to be explored. If you’re interested in learning more about clinical trials, talk with your doctor about whether there are any near you, and if participation in a trial might be an option.
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What Are Clinical Trials and Studies? National Institute on Aging. https://www.nia.nih.gov/health/what-are-clinical-trials-and-studies May 17, 2017. Accessed July 19, 2019.
After a Big Failure, Scientists and Patients Hunt for a New Type of Alzheimer’s Drug. NPR.org. https://www.npr.org/sections/health-shots/2019/05/03/718754791/after-a-big-failure-scientists-and-patients-hunt-for-a-new-type-of-alzheimers-dr May 3, 2019. Accessed July 19, 2019.
Nelson TJ, Sun M-K, Lim C, Sen A, Khan T, Chirila FV, et al. Bryostatin effects on cognitive function and PKC-epsilon in Alzheimer’s disease phase IIa and expanded access trials. Journal of Alzheimer’s Disease. 2017; 58(2): 521-535. Doi: 10.3233/JAD-170161. Accessed July 20, 2019.
Coughlan G, Coutrot A, Kohndoker M, Minihane A-M, Spiers H, & Hornberger M. Toward personalized cognitive diagnostics of at-genetic-risk Alzheimer’s disease. PNAS. 2019; 116(19), 9285-9292. Doi: https://doi.org/10.1073/pnas.1901600116 Accessed July 20, 2019.
Allison SL, Fagan AM, Morris JC, & Head D. Spatial navigation in preclinical Alzheimer’s disease. J Alzheimer’s Dis. 2016; 52(1), 77-90. Doi: 10.3233/JAD-150855 Accessed July 20, 2019.