Repurposed therapeutics in alzheimer’s disease: a comparative analysis of generic and patent-protected agents (2016–2025)

Repurposing approved drugs for Alzheimer’s disease (AD) offers a cost-effective strategy to accelerate therapeutic development. This study characterizes the role of repurposed agents in the 2025 AD drug development pipeline. Data was obtained from clinicaltrials.gov using an automated and curated process and analyzed as of January 1, 2025. Trials were categorized by therapeutic intent—disease-targeted therapies (DTTs) or symptomatic treatments (STTs) and by proprietary versus generic status. DTTs are drugs designed to interfere with the disease processes. STTs aim to improve cognition and behavior symptoms without altering the underlying disease processes. Phase distribution, biomarker use, sponsorship, and participant enrollment were assessed. Historical trends from 2016 to 2025 were examined. On the index date, 138 agents were in 182 AD clinical trials. Repurposed agents accounted for 46 (33%) of drug therapies and 68 (37%) of trials. Among repurposed agents, 41 were DTTs, 8 were cognition enhancers, and 19 were neuropsychiatric symptom treatments. Proprietary drugs comprised 37% of DTTs and 68% of neuropsychiatric symptom treatments. Biomarker use was common among trials of repurposed disease‑targeted therapies (85%), with biomarkers required for enrollment in 19 (83%) trials of generic agents and 15 (83%) trials of proprietary agents. Repurposed trials were most well represented in phase 2, where they compromised nearly 50% of the trials. Proprietary representation increased in later phases (76% of repurposed agents in phase 3). Industry sponsored 34% of repurposed trials, concentrated in phase 3 (71%). Repurposed agents enrolled 15,583 participants (31% of pipeline enrollment), with proprietary agents accounting for 62% of these participants. Three proprietary repurposed agents—semaglutide ® , xanomeline + trospium ® , and dextromethorphan + bupropion ® —were in global phase 3 trials. Biomarker use in repurposed trials increased by 125% since 2016, reflecting a shift toward precision medicine. Repurposed agents represent a significant component of the AD pipeline, particularly in disease-targeted strategies. Proprietary agents dominate late-phase trials and industry sponsorship, while generics are concentrated in early-phase research. Increasing biomarker integration underscores the evolution toward personalized therapeutic approaches.