A thorough clinical trial of a potential Alzheimer’s drug has failed to prevent or delay cognitive decline, yet another disappointment in the long and difficult search for solutions to this disease.
The decade-long trial was the first time that people with a genetic predisposition to develop the disease, but not yet showing any symptoms, were given a drug designed to halt or slow the decline in brain function.
The participants were members of an extended family of 6,000 people in Colombia, about 1,200 of whom have a genetic mutation that virtually determines that they will develop Alzheimer’s between the ages of 40 and 50.
For many family members, who live in MedellÃn and remote mountain villages, the disease quickly robbed them of their ability to work, communicate and perform basic functions. Many died in their 60s.
In the study, 169 people with the genetic mutation were given either a placebo or the drug crenezumab, produced by Genentech, part of the Roche Group. Another 83 people without the mutation were given the placebo as a way of protecting the identity of people likely to develop the disease, which is highly stigmatized in their communities.
The researchers hoped that intervention with a drug years before memory and thinking problems appeared could keep the disease in check and provide important information for dealing with the most common type of Alzheimer’s, which is not caused by a single genetic mutation.
“We are disappointed that crenezumab did not have a significant clinical benefit,” Eric Reiman, executive director of the Banner Alzheimer’s Institute, a research and treatment center in Phoenix, Arizona, and leader of the research team, said in an interview. conference on the results.
“Our hearts go out to the families in Colombia and all others who would benefit from effective Alzheimer’s prevention therapy as soon as possible. At the same time, we are excited to know that this study launched and continues to help shape a new era. in Alzheimer’s prevention research.”
The results are also another setback for drugs that target a key element in the disease: the amyloid protein, which forms sticky plaques in patients’ brains. Years of studies of various drugs that attack amyloid at different stages of the disease have fallen apart.
In 2019, Roche suspended two other trials of crenezumab, a monoclonal antibody, in people in the early stages of the more typical Alzheimer’s disease, saying the studies were unlikely to reveal benefits.
Last year, in a highly controversial decision, the US Food and Drug Administration (FDA) granted its first approval for an anti-amyloid drug, Aduhelm.
The FDA acknowledged that it was unclear whether Aduhelm could help patients, but it gave the green light to a program that allows authorization of drugs with uncertain benefits if they are for serious conditions with few treatments and if the drugs affect a biological mechanism with reasonable probability. to help patients.
The agency said the biological mechanism was Aduhelm’s ability to attack amyloid, but many Alzheimer’s experts criticized the decision because of the poor track record of anti-amyloid therapies. The results of the study, released on Thursday, only added to the discouraging evidence.
“I wish there was something more positive to say,” said Dr. Sam Gandy, director of the Center for Cognitive Health at Mount Sinai, who was not involved in the research in Colombia.
“The pathogenic mutation in the Colombian family is known to be involved in amyloid metabolism,” Gandy said, adding, “The idea was that these were the patients most likely to respond to anti-amyloid antibodies.”
The Doctor. Pierre Tariot, director of the Banner Alzheimer’s Institute and leader of the Colombian research, said that some of the data suggested that patients who received crenezumab fared better than those who received the placebo, but the differences were not statistically significant.
He also said there were no safety issues with the drug, an important finding because many anti-amyloid therapies, including Aduhelm, have caused bleeding or brain swelling in some patients.
Additional data from the study will be presented at a conference in August. Tariot and Reiman noted that the latest results did not include more detailed information from brain scans or blood tests about the drug’s effects on proteins and other aspects of the biology of Alzheimer’s disease.
They also did not reflect increases in the dose of crenezumab, which researchers began giving patients as they learned more about the drug, Tariot said. He said some patients received the highest dose for up to two years of the five to eight years they participated in the clinical trial.
The Doctor. Francisco Lopera, a Colombian neurologist and another research leader, began working with family members decades ago and helped determine that his disease was a genetic form of Alzheimer’s. He said the study convinced him that “prevention is the best way to find a solution for Alzheimer’s disease, even if we don’t have a good result today.”
Translated by Luiz Roberto M. Gonçalves
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