Biogen’s stock rose 1% Thursday, after Europe’s pharmaceutical regulator issued a positive opinion on the Alzheimer’s disease drug that the company developed with Japanese partner Eisai — reversing an earlier decision not to approve the drug.

The European Union's drugs regulator on Thursday recommended approval for Eisai and Biogen's Leqembi in some patients with early Alzheimer's disease, nearly four months after it first rejected the treatment.

The European Union's drugs regulator reversed its decision to block the Alzheimer's drug lecanemab, a treatment aimed at slowing cognitive decline in patients. In July, the Amsterdam-based European Medicines Agency (EMA) denied recommending approval of the drug made by Eisai and Biogen because it considered the risks - especially bleeding and swelling in the brain - to be greater than the potential benefits in a broad population.