“LEQEMBI”, the world's first disease-modifying therapy for Alzheimer's disease (AD), was approved in Japan in September of this year, following the United States, ushering in a new era in dementia treatment. Eisai Co., Ltd. has been engaged in research and development in the field of dementia for more than 40 years, continuing to overcome failures and diversify R&D risks. Although we succeeded in developing the world's first AD drug "ARICEPT" in 1997, we continued to strive for next-generation drug discovery. We have developed a variety of new drug candidates based on the amyloid-β (Aβ) cascade hypothesis, which is the root cause of AD, but candidates have dropped out one after another. Among them, the anti-Aβ protofibril antibody “LEQEMBI” was developed through careful clinical research, utilizing the results of familial AD research conducted in collaboration with academia. There is no success in drug discovery without failure, and by enduring failure, experience and knowledge are accumulated. This experiential knowledge is the key to success in drug discovery and is the “nautical chart” that guides the ship of new drug development on the right course. The presence of a captain who writes the charts and navigates the sea is also essential. I would like to take this opportunity to touch on “the spirit of drug discovery” that exists based on empathy with AD patients.