Alzheimer’s breakthrough? Not so fast, say critics of new study
Alzheimer’s breakthrough?
Results from a new study on Alzheimer’s disease have produced controversy within the scientific community as some have called the findings a positive and “heartening” step in treating the disease while others are slamming the study’s research team for “cherry picking” data from a study with overall negative results.
Researchers presented their findings this week at the Alzheimer’s Association International Conference in Toronto on a highly anticipated clinical trial for a drug called LMTX, meant to counter the effects of dementia and Alzheimer’s by dissolving a protein build-up in the brain which by some accounts may play a role in the progression of the disease.
The trial results have been described is vastly different terms. It’s either a breakthrough or a failure, depending upon the source.
The drug trial involving 891 patients with mild to moderate Alzheimer’s took place over 18 months and had patients taking a variety of drugs meant to improve cognitive functioning and slow the progression of Alzheimer’s. Overall, the study’s results showed that LMTX did not have an effect on the progression of dementia as measured by cognitive test scoring, functional test scoring and brain scans. Yet the research team chose to present a key subset of their findings on its own, one in which roughly 15 per cent of the trial group (136 of 891 patients) took only LMTX without the other cognition-enhancing drugs. According to the researchers, the results from that subset were positive along all three cognitive, functional and brain volume measures.
“While the TRx-237- 015 study in 891 subjects failed to meet its co-primary endpoints, clinically meaningful and statistically significant reductions in the rate of disease progression were observed across three key measures in patients who were treated with LMTX® as their only Alzheimer’s disease medication,” reads the report from TauRx Pharmaceuticals, makers of LMTX.
The company’s results have been lauded by some as unprecedented and a “first” in Alzheimer’s treatment while others have been more cautious, some registering criticism of a practice called outcome switching, often associated with a bias in study reporting. “Registered primary outcome measures should form the basis of any conclusion,” says Chris Chambers, professor of cognitive neuroscience at Cardiff University in Wales. “Any subgroup analyses should be strongly caveated, if reported at all.”
Yet some see even the altered results of the LMTX study as promising. In presenting the trial results at the Alzheimer’s conference, Serge Gauthier, Director of the Alzheimer’s Disease Research Unit at McGill University in Montreal, said “In a field that has been plagued by consistent failures of novel drug candidates in late-stage clinical trials, and where there has been no practical therapeutic advance for over a decade, I am excited about the promise of LMTX as a potential new treatment option for these patients.”
Roughly 564,000 Canadians currently live with dementia, a number that is expected to increase sharply as the country’s current population ages. According to the Alzheimer’s Society of Canada, 937,000 Canadians are projected to be afflicted with dementia by the year 2031.