The hotly anticipated results of a clinical trial of an experimental Alzheimer’s drug suggest that the treatment slowed cognitive decline for people in the early stages of the disease but also caused some patients to experience brain swelling or brain bleeding.

The new data, released on Wednesday AEDT, offered the first detailed look at the effects of the drug, lecanemab, and comes two months after its manufacturers, Eisai and Biogen, stoked excitement by announcing that the drug had shown positive results.