New Genentech Study to Investigate Familial Alzheimer’s Progression and Response to Crenezumab

Ana Pena, PhD avatar

by Ana Pena, PhD |

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Long-term trial of bryostatin-1 for Alzheimer's

Genentech, a subsidiary of Roche, has launched a new substudy to learn more about the progression of early-onset familial Alzheimer’s disease, as part of its ongoing Alzheimer’s Prevention Initiative (API) trial evaluating crenezumab for preventing or delaying this genetic form of the disease.

This substudy will examine the effects of presymptomatic treatment with crenezumab — an investigational anti-amyloid antibody under development by AC Immune and Genentech — on tau accumulation in the brains of patients at risk of familial Alzheimer’s.

Data is expected to advance the understanding of how tau burden relates to disease progression and how it can be used to track crenezumab’s efficacy in patients who respond to treatment.

“Learning more about the early distribution and severity of Abeta [beta amyloid]- and tau-related pathology in AD [Alzheimer’s disease] is imperative in developing successful Alzheimer’s treatments. This new substudy will provide further evidence on the progression of familial AD by monitoring for changes in Tau burden and help examine the potential role of crenezumab as a disease-modifying agent that may prevent the onset or slow progression in people at risk of developing familial AD,” Andrea Pfeifer, CEO of AC Immune, said in a press release.

The study is part of API’s Phase 2 Autosomal Dominant Alzheimer’s Disease Colombia Trial (NCT01998841), which began in 2013 and is being led by Banner Alzheimer’s Institute in Arizona, the University of Antioquia in Colombia, Genentech, and Roche.

It enrolled about 200 members of an extended family in Colombia where several members carry the E280A mutation on the PSEN1 gene, one of the most common causes of early-onset familial autosomal dominant Alzheimer’s.

Carriers of this mutation risk developing Alzheimer’s at unusually young ages, typically around 45 years old.

The study’s main goal is to determine if administering crenezumab prior to symptom onset can slow or prevent the decline in cognitive and functional abilities in this at-risk population.

According to AC Immune, therapeutic interventions tested to date may not have been started early enough or in the period preceding the emergence of symptoms, so there may be an opportunity for early intervention with a therapy such as crenezumab.

During the trial, carriers of the PSEN1 E280A mutation without cognitive impairment receive crenezumab either intravenously (into the vein) or under the skin for at least 260 weeks.

In the sub-study (NCT03977584) now being launched, some of the participants will receive up to three intravenous injections of Genentech Tau Probe 1 and undergo a positron emission tomography (PET) scan after each injection to measure tau burden in the brain. 

Tau proteins are normally abundant inside nerve cells, but in people with Alzheimer’s, abnormally twisted fibers of tau, or tau tangles, spread throughout the brain in a fashion that matches both clinical symptoms and disease progression. Tau Probe 1 is a tracer that is able to selectively image tau tangles in specific regions of the brain using PET scans.

The substudy’s primary outcome is to measure the change over time in tau distribution, determined at week 130 and up to week 260 of the main study.

“Treating earlier and testing in homogeneous populations are two important elements in AC Immune’s Roadmap to success and, both strategies are being applied in the API trial. Testing therapeutics in a homogeneous group in people carrying the PSEN1 E280A mutation earlier in the preclinical development phase, may make it possible to identify successful treatment strategies for treating this debilitating disease,” Pfeifer said.