According to the National Council on Patient Information and Education (NCPIE), most older Americans (8 out of 10) take at least one medication and many take three or more per day.
This patient group accounts for not only 34% of all prescription medicine use but also 30% of all over-the-counter (OTC) medicine use.
Clinical trial completion and compliance pose unique challenges in older patients, said Joyce Suhy PhD, the head of neuroscience and cardiovascular services at Bioclinica.
“Sometimes they may lose interest or their health declines to a point where they can no longer participate while others move away and need to drop out of the trial,” Suhy told us.
Additionally, in the geriatric population, she noted the presence of “snowbirds,” or those who move from one location to another during the winter. These patients may stop participating in the trial while they are away, though study teams can account for this early by directing patients to a local site at a second location, she explained.
Technological capability in older patients also can impede trials. However, this challenge can be overcome through training and by implementing easier to use tools and applications.
“Another challenge is variable response to treatment due to concomitant conditions in this population,” Suhy said, as these medications could potentially interfere with the drug efficacy assessment of the study.
A deteriorating condition also may make it more difficult or impossible for seniors to complete clinical trials. “Elderly, particularly those with compromised health, may lack strength, making it more difficult than a younger person to endure the various aspects of the trial,” said Suhy.
Approximately 5.7m Americans suffer from Alzheimer’s, and while some of these individuals are not senior citizens, 5.5m are over the age of 65. The disease is the sixth leading cause of death in the US and – combined with other dementias – is expected to cost the nation $227bn by 2050, according to the Alzheimer’s Association.
But while there are many of the same challenges in Alzheimer’s trials as in geriatrics, Suhy explained there are other unique issues: “For one, informed consent is more complicated,” she said.
Additionally, a caregiver who is willing to help navigate an Alzheimer’s patient through the trial process is generally required. “Identifying the right patient thus also requires identifying the right caregiver,” explained Suhy.
Correct diagnosis is not always certain either. Suhy said, “The Alzheimer’s diagnosis is a difficult one to make. Patients who may not have the appropriate diagnosis are introduced into the screening process…Trial candidacy is often not confirmed until the PET scan, which is the last exam in the screening window.”
There also are patients in Alzheimer’s studies who after receiving a positive PET scan no longer wish to participate in the trial. The focus of the patient moves to their health and attendance of their family and the implications of the PET scan results.
Eli Alford the COO of Schulman IRB previously told us, “Lower participation rates mean slower studies, delayed results and ultimately delayed advancements in prevention, diagnosis, and treatment. That’s the challenge.”
Also, because the PET scan is the last exam in the screening process, the screen failure rate in Alzheimer’s trials is as high as 30-60%, Suhy explained. “This increases trial costs and turns away patients after they’ve gone through the entire screening process,” she added.
There also is no clear validated biomarker that correlates well with clinical endpoints, meaning drug efficacy evaluation relies primarily on clinical endpoints with high variability.
However, biomarkers can indicate susceptibility and prognosis of Alzheimer’s according to the Alzheimer’s Drug Discovery Foundation.
The US Food and Drug Administration (FDA) is reviewing possible qualification of biomarkers that can determine Alzheimer’s prognosis, but more diagnostic tools are needed since beta-amyloid PET scans are not definitive, and response and monitoring biomarkers are not currently present.
“We are encouraged by recent advancements in biomarker research using quantitative measures of AD amyloid and tau pathology as well as brain atrophy,” Suhy said.