Alzheimer’s drug falters in trials
Small group of patients who took only LMTX had better outcomes, but it’s unclear why
A new type of drug for Alzheimer’s disease failed to slow the rate of decline in mental ability and daily functioning in its first large clinical trial. There was a hint, though, that it might be effective for certain patients.
The drug, called LMTX, is the first one with its mode of action — trying to undo so-called tau tangles in the brain — to reach the final stage of clinical trials. So the results of the study were eagerly awaited. The initial reaction to the outcome was disappointment, with perhaps a glimmer of hopefulness.
Overall, the patients who received LMTX, which was developed by TauRx Therapeutics, did not have a slower rate of decline in mental ability or daily functioning than those in the control group.
However, the drug did seem to work for the subset of patients — about 15 percent of those in the study — who took LMTX as their only therapy. The other 85 percent of patients took an existing Alzheimer’s drug in addition to either LMTX or a placebo.
“There were highly significant, clinically meaningful, large effects in patients taking the drug as monotherapy, and no effect in patients taking it as an add-on,” Claude Wischik, a founder and the chief executive of TauRx, said in an interview. He spoke from Toronto, where the results were being presented at the Alzheimer’s Association International Conference.
Wischik said a second clinical trial sponsored by the company, whose results will be announced later, found the same phenomenon. He said the company planned to apply for approval of LMTX to be used by itself.
But some experts not involved in the study were skeptical about drawing conclusions from a small subset of patients, especially since there was no obvious explanation why LMTX would be expected to work only in patients not getting other drugs. Regulators might also be skeptical and require the company to conduct another large study, this time only with participants not using other drugs.
“I have to say that the results that we saw here were, to me, more disappointing than not,” Dr. David Knopman, a neurologist at the Mayo Clinic, said in moderating a news conference at the meeting in Toronto.
Dr. Rachelle Doody, director of the Alzheimer’s disease and Memory Disorders Center at Baylor College of Medicine, agreed.
“To present it to the public now as a promising approach seems unjustified,” she said.
The Alzheimer’s field is littered with unsuccessful experimental drugs. The handful of drugs that have reached the market, like Aricept and Namenda, temporarily affect symptoms but do not hit at the underlying mechanism of the disease.