Dr. Thambisetty said the two deaths raise questions about the safety issues of lecanemab “in real-world clinical practice, where patients are more likely to be sicker and have multiple other medical conditions, as opposed to carefully selected patients in clinical trials.”
Nevertheless, the data on lecanemab, which Dr. Gandy noted that it attacks a different form of amyloid than previously tested drugs, significantly less swelling and bleeding than with Aduhelm.
Nearly 13 percent of patients receiving lecanemab experienced brain swelling, which was mild or moderate in most cases, while less than 2 percent of patients receiving the placebo experienced such swelling, the study reported. Most brain swellings caused no symptoms and generally resolved within a few months. About 17 percent of lecanemab patients experienced cerebral hemorrhages, compared with 9 percent of patients who received the placebo. The most common symptom of brain hemorrhage was dizziness, the study said.
The authors reported that “serious side effects” occurred in 14 percent of lecanemab patients and 11 percent of those receiving placebo. Nearly 7 percent of lecanemab patients dropped out of the study due to negative side effects, more than twice the percentage of placebo recipients who dropped out. More than a quarter of lecanemab patients experienced adverse infusion-related reactions, including fever and flu-like symptoms, mostly with the first dose. A much smaller percentage of placebo patients experienced those reactions, the study found.
The main positive outcome of the study was that lecanemab patients experienced a cognitive decline of 1.21 points, while patients receiving placebo decreased 1.66 points on the 18-point scale, which assesses functions such as memory, problem solving and daily activities through patient interviews and healthcare providers. .
This result was supported by secondary measures in the trial, including three other cognitive tests, which reinforce the possibility that the drug has a real-world effect, experts said. In addition, across all measures, patients began to show slower progression several months after starting lecanemab, and the rate slowed further during the 18-month trial.
The trial made an effort to include more participants of color than are normally enrolled in Alzheimer’s disease. About 25 percent of those participating in the trial in the United States were black or Hispanic, the study reported. It also enabled people with a variety of medical conditions to participate, including hypertension, diabetes, heart disease, obesity and kidney disease.
