Despite the popularity of amyloid beta-targeting drugs, none have managed to pass late stage clinical trials, prompting UMC Radboud to halt its own studies.

In the latest blow to the amyloid beta hypothesis, Radboud University Medical Centre in Nijmegen, the Netherlands, announced that it will no longer continue studies into drugs targeting misfolded amyloid beta. These proteins clump together and form plaques—one of the telltale signs of Alzheimer’s disease.

Toxic amyloid built up has been the dominant theory of Alzheimer’s for almost three decades, but there is still no drug on the market that can successfully treat the disease by addressing this process. “I simply cannot sell it anymore to my patients,” Marcel Olde Rikkert, Head of Geriatrics at Radboud University Medical Centre, told the Dutch newspaper, De Volkskrant on February 4.

He noted that Alzheimer’s pathology, particularly in older individuals, goes beyond the amyloid beta clumps, adding that, “With elderly people, we often have a mixed picture of Alzheimer’s and other forms of dementia,