Clinical trials face severe patient recruitment shortage across cancer and Alzheimer's disease

Clinical trials face a severe global participant shortage, with only 7% of US adult cancer patients enrolling and over 20% of oncology trials terminating early due to under-enrollment. Meanwhile, 192 active dementia trials require 350,000 applicants to sustain progress. This crisis is driven by structural barriers rather than patient unwillingness. Outdated registries index trials by organ type instead of molecular biomarkers, and AI investments remain heavily skewed toward sponsors rather than patient-facing discovery tools.

Clinical trial patient recruitment crisis

• ▪An estimated 350,000 applicants are required globally to sustain the 192 active clinical trials testing 158 potential dementia therapies.
• ▪Only about 7% of adult cancer patients in the United States enroll in clinical trials, leaving over 90% treated entirely outside of trial frameworks.
• ▪More than 20% of oncology clinical trials fail to meet enrollment targets and are subsequently terminated early, driving up drug development costs.

Structural barriers to trial discovery

• ▪Alzheimer's Disease International reported that limited awareness of trial opportunities and misunderstandings about research hamper global participation in dementia trials.
• ▪A meta-analysis by Unger and colleagues found that structural barriers, specifically the lack of local trial availability, cause 56% of patient non-participation.
• ▪Noriyo Washizu of Alzheimer's Association Japan stated that a pervasive paternalistic medical culture in Japan limits patient support for making independent trial decisions.

Physician-dependent information channels

• ▪Cancer patients in the United States rely almost exclusively on their treating physicians to learn about active clinical trials.
• ▪Oncology physicians frequently restrict clinical trial referrals to studies operating within their own institutions and networks due to brief patient visits.

Biomarker-driven trial classification gaps

• ▪Public clinical-trial registries index trials primarily by tumor type, preventing patients from finding modern biomarker-driven, tumor-agnostic trials organized around molecular targets.
• ▪The FDA released final guidance in December 2025 to boost trial participation, followed by two real-time clinical trial pilots in April 2026.

AI investment asymmetry in recruitment

• ▪The FDA opened a request for public comment on utilizing artificial intelligence and data methods to improve clinical trial efficiency.
• ▪Artificial intelligence investments in clinical trials are heavily concentrated on helping sponsors identify patient populations rather than helping patients discover trials.