Biogen stock surges 40% after Alzheimer's treatment win

Biogen Inc. rose the most since November 2020 after a key clinical trial with its partner Eisai Co. showed that the therapy lecanemab slowed the progression of Alzheimer's disease.

After the clinical win, the stock went 40%, reversing this year's decline and adding more than $11 billion in market value. Other firms developing treatments for the disease are higher Wednesday after the data was released, helping lift a gauge of biotechnology stocks to its best day since Aug. 4.

Biogen shares had been rocked over the past few years due to developments around its controversial Alzheimer's treatment Aduhelm, which won approval from the FDA last year, but was hit by limited coverage from Medicare. A trio of brokers have upgraded the stock to buy-equivalent ratings after the lecanemab trial met the main goal, which has led to a rise in regulatory success, according to analysts.

Baird analysts Brian Skorney wrote in a note that the reported data is a best-case scenario that should not only lead to approval and reimbursement but could make it difficult for competition if any are successful to match.

Biogen's partner Eisai increased by 17% in Tokyo, while BioArctic AB, which the therapy was originally licensed from, surged more than 170%.

Other companies developing treatments for the neurodegenerative disease have gained. Eli Lilly and Co., which is studying donanemab for early Alzheimer s, climbed 7.5% the most since December to close at a record high level. Prothena Corp. went 88% and Acumen Pharmaceuticals Inc. jumped 104%, each posting their biggest gains on record.

The Supreme Court Doesn't Display Its Power Imbalance Again?