Alzheimer’s disease may be caused by buildup of protein plaques and tangles in the brain andrew brooks
A drug called lecanemab is the first to be shown to slow early Alzheimer’s disease。 It also reduces plaque and tangles in the brain that are thought to contribute to disease progression.
While this sounds promising, some have questioned whether these effects are large enough to have a meaningful impact on Alzheimer’s symptoms.
Potential concerns have also been raised about the drug’s safety. In an 18-month study of nearly 1,800 early-stage Alzheimer’s patients, 0.7% of those who received lecanemab died, compared with 0.8% of those who received a placebo infusion.
In a statement issued on November 30Japan’s Eisai Pharmaceuticals, which develops lecanemab, said none of the deaths were related to the drug. However in October, Statistical data Lecanemab has been reported to have possibly contributed to the death of one participant. November 27, science A second participant reportedly died of a massive brain hemorrhage, which some researchers have linked to lecanemab.
Notice from Eisai science That, while unable to comment on individual cases due to privacy concerns, “all available safety information indicated that lecanemab treatment was not associated with an increased risk of death overall or any specific cause”.
However, the reports have prompted some to question whether the benefits of lecanemab outweigh its potential risks, proposed question new scientist When Eisai releases preliminary results in late September.
Lecanemab binds to and removes clumps of protein called amyloid plaques in the brain.Researchers have believed for decades that these plaques are the main cause of Alzheimer’s disease, but many treatments targeting them have shown no benefit in trials, including controversial drugs Aducanumab.
In a phase III trial, early-stage Alzheimer’s patients aged 50 to 90 received either lecanemab or a placebo intravenously every two weeks for 18 months. All participants had evidence of amyloid buildup in their brains.
Christopher Van Dyke At the Yale School of Medicine in Connecticut and colleagues measured participants’ cognitive function before the trial and then every three months until month 18. This was assessed through interviews with participants and their carers. Participants also completed questionnaires assessing their quality of life before, during and after the study.
By the end of the trial, both groups showed signs of cognitive decline. However, the lecanemab group was on average 27 percent slower than the control group. Although this seems significant, the effect is very small – a difference of 0.45 points on a scale of 0 to 18.
“Most Alzheimer’s experts agree that a 20 to 30 percent slowdown in this very severe disease would be meaningful for patients,” the researchers said Sharon Cohenat a press conference held by Eisai in late November, at Canada’s Toronto Memory Project.
Lecanemab also appears to have a cumulative effect, Cohen said. Statistical models suggest that about two years of treatment can delay Alzheimer’s disease progression by up to three years.
In terms of quality of life, compared with the lecanemab group, the control group experienced an average reduction of about 50% from the start to the end of the study, according to the results of the 2022 Alzheimer’s Disease Clinical Trials meeting in San Francisco, CA.
Some of the roughly 400 participants also underwent brain scans to assess them for any changes in amyloid plaques. Amyloid scores were reduced by an average of about 70 percent in patients treated with lecanemab from the start to the end of the trial. In contrast, scores in the control group improved by nearly 5 percent on average.
The lecanemab group also greatly reduced the amount of misfolded proteins called tau tangles in the brain. These proteins were increased in the control group. “Tau is the abnormal protein in Alzheimer’s disease that correlates best with clinical decline,” said Leah Greenberg at the University of California, San Francisco.
Overall, the results sound promising, but the trial raised some concerns about the drug’s safety.
More than 17 percent of people in the lecanemab group had some degree of cerebral hemorrhage, compared with 9 percent of people in the placebo group. In addition, nearly 13 percent of patients who received the drug experienced brain swelling and inflammation, compared with less than 2 percent of those who received a placebo infusion.
“Some say the drug is too small to be worth it, especially in high-risk groups [of complications]’ said Greenberg.
In its Nov. 30 press release, Eisai said: “The convergence of evidence on cognition and function, disease progression, health-related quality of life, and caregiver burden suggests that lecanemab treatment has the potential to benefit patients, their care partners, physicians and society. bring meaningful benefits”
Journal reference: New England Journal of Medicine, DOI: 10.1056/NEJMoa2212948
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