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Eisai makes and sells prescription medicines and over-the-counter drugs, with a big focus on brain and cancer treatments.
Eisai is a Japanese drugmaker that sells prescription medicines and over-the-counter products to healthcare markets around the world. Two areas matter most: neurology, meaning brain and nerve diseases, and oncology, meaning cancer. Ordinary shoppers mostly meet Eisai through its consumer health products, but the serious money comes from prescription drugs sold to hospitals, doctors, and insurers.
The company's most famous medicine is lecanemab, sold as Leqembi, an Alzheimer's drug developed with Biogen. It is given to patients in the early stages of the disease and works by clearing sticky amyloid plaques from the brain. The drug has won full approval in the United States, Japan, and other markets, and it is Eisai's biggest swing at growth. The catch is that it requires regular infusions and brain scans to watch for swelling or bleeding, so adoption has been slower and more complicated than the hype suggested. Eisai also sells older mainstays. Lenvima, a cancer drug, is marketed with Merck and brings in steady revenue through a profit-sharing deal. Halaven treats breast cancer and liposarcoma. On the consumer side, the company sells a wide range of over-the-counter medicines and supplements, mostly in Japan and Asia. That mix gives Eisai stable cash from everyday products while it bets heavily on risky new science.
The bet is expensive. Leqembi's rollout has been slow, and Eisai has been spending hard to build the infrastructure around it. The company has also been trimming its pipeline, cutting jobs, and weighing a possible listing of its consumer health business to raise cash and focus on prescription drugs. That is the core tension: Eisai is a century-old company with reliable products trying to become a major player in Alzheimer's, a disease that has defeated nearly everyone who tried before. If Leqembi works commercially, it is a huge win. If not, the older drugs have to carry the load.
Saved answer 路 last researched 15 Nov 2026