The study examines the Alzheimer's disease (AD) drug-development pipeline from 2002 to 2012 using data from Clinicaltrials.gov. During this period, 413 AD trials were conducted, with a high attrition rate and a low success rate for advancing from one phase to the next. The majority of trials were sponsored by pharmaceutical companies, and the United States had the highest number of trials. Most trials focused on symptomatic agents aimed at improving cognition, followed by disease-modifying small molecules and immunotherapies. The mean length and number of participants increased from Phase 2 to Phase 3, with disease-modifying agents requiring larger and longer trials. The overall success rate for advancing agents to regulatory review was 0.4%, with a very high attrition rate of 99.6%. The current AD pipeline is relatively modest, and there is an urgent need to increase the number of agents entering the pipeline and progressing successfully toward new therapies.The study examines the Alzheimer's disease (AD) drug-development pipeline from 2002 to 2012 using data from Clinicaltrials.gov. During this period, 413 AD trials were conducted, with a high attrition rate and a low success rate for advancing from one phase to the next. The majority of trials were sponsored by pharmaceutical companies, and the United States had the highest number of trials. Most trials focused on symptomatic agents aimed at improving cognition, followed by disease-modifying small molecules and immunotherapies. The mean length and number of participants increased from Phase 2 to Phase 3, with disease-modifying agents requiring larger and longer trials. The overall success rate for advancing agents to regulatory review was 0.4%, with a very high attrition rate of 99.6%. The current AD pipeline is relatively modest, and there is an urgent need to increase the number of agents entering the pipeline and progressing successfully toward new therapies.