Visit the News Hub

International clinical trial yields mixed results with unclear cognitive effects but promising biomarker results

Randall Bateman, MD, director of the Dominantly Inherited Alzheimer Network-Trials Unit (DIAN-TU), an ongoing international clinical trial to evaluate experimental Alzheimers drugs, speaks with DIAN-TU participant Taylor Hutton. One of the drugs tested in the DIAN-TU, gantenerumab, improved biomarkers of disease despite unclear cognitive effects, prompting study leaders to offer participants the option of continuing to receive the drug and participate in follow-up examinations as part of a so-called open label extension.

An investigational Alzheimers drug reduced molecular markers of disease and curbed neurodegeneration in the brain, without demonstrating evidence of cognitive benefit, in a phase 2/3 clinical trial led by researchers at Washington University School of Medicine in St. Louis through its Dominantly Inherited Alzheimer Network-Trials Unit (DIAN-TU). These results led the trial leaders to offer the drug, known as gantenerumab, to participants as part of an exploratory open-label extension. The researchers continue to monitor changes in measures of Alzheimers disease in those participants who are receiving the drug.

The DIAN-TU study (ClinicalTrials.gov Identifier: NCT01760005), published June 21 in Nature Medicine, evaluated the effects of two investigational drugs gantenerumab, made by Roche and its U.S. affiliate, Genentech, and solanezumab, made by Eli Lilly and Co. in people with a rare, inherited, early-onset form of Alzheimers known as dominantly inherited Alzheimers disease or autosomal dominant Alzheimers disease. Such people are born with a mutation that causes Alzheimers, and experience declines in memory and thinking skills starting as early as their 30s or 40s.

Gantenerumab had a major impact on Alzheimers biomarkers, said principal investigator Randall J. Bateman, MD, director of DIAN-TU and the Charles F. and Joanne Knight Distinguished Professor of Neurology at Washington University. The drugs ability to shift multiple Alzheimers biomarkers toward normal indicates that it is positively affecting the disease process. The effect was strong enough that we launched an open-label extension of the trial so participants have the opportunity to stay on the drug as we continue to study it.

Over the past few decades, scientists have pieced together the changes that occur as Alzheimers develops, a process that takes 20 years or more. First, the protein amyloid beta starts forming plaques in the brain. Later, levels of tau and neurofilament light chain rise in the cerebrospinal fluid that surrounds the brain and spinal cord, and the brain begins to shrink. Then, tangles of tau protein form in the brain. Only then do people with the disease start exhibiting signs of memory loss and confusion.

In this study, 52 patients were randomized to gantenerumab, which led to a reduction in the amount of amyloid plaques in the brain, and lowered soluble tau and phospho-tau, and slowed the rise of neurofilament light chain levels in the cerebrospinal fluid. Neurofilament light chain is a marker that reflects neurodegeneration. Overall, gantenerumabs safety profile in this trial was consistent with that from other clinical trials of the investigational medicine, and no new safety issues were identified.

The primary endpoint of the DIAN-TU study was the prevention or slowing of cognitive decline in people who are nearly certain to develop Alzheimers due to genetic mutations. Neither drug met the primary endpoint, although the study wasnt able to determine effects on thinking and memory in participants who entered the study without symptoms, because they exhibited little to no decline in cognitive function. The study also was unable to assess the effects of higher doses of the drugs, which were escalated to the desired levels late in the trial after a protocol amendment. Participants who received gantenerumab started on a low dose and only started ramping up to a fivefold higher target dose about halfway through the trial, prompted by observations from other studies of gantenerumab.

However, as a secondary endpoint, the study also evaluated the effect of the drugs on molecular and cellular signs of Alzheimers disease. On these measures, gantenerumab showed potential benefit.

These biomarker results suggest that gantenerumab had a favorable impact on the target and downstream markers of Dominantly Inherited Alzheimers Disease, said Rachelle Doody, MD, PhD, global head of neurodegeneration at Roche and Genentech. We support the continued scientific investigation of gantenerumab in Washington Universitys exploratory, open-label extension study to build on learnings from DIAN-TU-001, and are grateful to be a part of this close collaboration between industry, academia and patients as we continue to tackle the complex challenge of Alzheimers disease. We are encouraged by the advancements being made and look forward to continued progress for people with Alzheimers disease.

This trial followed 144 participants for up to seven years; the average follow-up was about five years. All participants carry a genetic mutation that causes a form of Alzheimers dementia at early ages. The researchers recruited participants who were expected to develop symptoms within 15 years or who already had very mild symptoms of memory loss and cognitive decline at the trials outset. In most cases, their brains already showed early signs of disease. Participants were randomly assigned to receive solanezumab, gantenerumab or a placebo.

Although the trial focuses on people with rare mutations, drugs that are successful in this population would be promising candidates for preventing or treating the forms of Alzheimers that occur more commonly in older adults. The destructive molecular and cellular processes in the brain are similar in both types of the disease, Bateman said.

Salloway S, Farlow M, et al. A Trial of Gantenerumab or Solanezumab in Dominantly Inherited Alzheimers Disease. Nature Medicine. June 21, 2021. DOI: 10.1038/s41591-021-01369-8

Data analyzed in this paper was obtained with the support of the National Institute on Aging of the National Institutes of Health (NIH), grant numbers U01AG042791, U01AG042791-S1, R01AG046179, R01AG053267-S1 and U19AG032438; the Alzheimers Association; Eli Lilly and Co.; Roche and Genentech, a member of the Roche group; Avid Radiopharmaceuticals; GHR Foundation; an anonymous organization; Cogstate; Signant; the German Center for Neurodegenerative Diseases; the Raul Carrea Institute for Neurological Research; the Japan Agency for Medical Research and Development; and the Korea Health Industry Development Institute.

Washington University School of Medicines 1,500 faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Childrens hospitals. The School of Medicine is a leader in medical research, teaching and patient care, consistently ranking among the top medical schools in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Childrens hospitals, the School of Medicine is linked to BJC HealthCare.

Go here to see the original:
Investigational Alzheimer's drug improves biomarkers of the disease Washington University School of Medicine in St. Louis - Washington University...