RESUMO
INTRODUCTION: With the exception of the recent accelerated approval of aducanumab, in over 26 years of research and development (R&D) investment in Alzheimer's disease (AD), only five novel drugs-all for symptomatic treatment only-have reached FDA approval. Here, we estimate the costs of AD drug development during this period in the private sector. METHODS: To estimate private R&D funding, we collected information on AD clinical trials (n = 1099; phases 1-4) conducted between January 1, 1995 and June 21, 2021 from various databases. Costs were derived using previously published methodologies and adjusted for inflation. RESULTS: Since 1995, cumulative private expenditures on clinical stage AD R&D were estimated at $42.5 billion, with the greatest costs (57%; $24,065 million) incurred during phase 3; approximately 184,000 participants were registered or are currently enrolled in clinical trials. DISCUSSION: Measures to reduce expenditures while moving toward disease-modifying therapies that alleviate the rising burden of AD require continued investment from industry, government, and academia.