Top-line results from the seminal phase 2/3 Dominantly Inherited Alzheimer’s Network–Trials Unit (DIAN-TU) study show that the novel drugs gantenerumab (Roche) and solanezumab (Lilly) did not meet the primary endpoint in patients with early-stage, dominantly inherited Alzheimer’s disease (AD), investigators have announced.
In the international trial, which included almost 200 participants, the two experimental agents were evaluated separately. However, initial analyses showed that neither significantly slowed cognitive decline, the primary outcome measure, nor memory loss.
Still, the researchers noted that they will continue exploring data from DIAN-TU’s cognitive and clinical outcomes and are awaiting analyses of various biomarkers.
“Although the drugs we evaluated were not successful, the trial will move us forward in understanding Alzheimer’s,” principal investigator Randall J. Bateman, MD, of Washington University, St. Louis, said in a news release.
Funders for the trial included the National Institute on Aging and the Alzheimer’s Association.
“While the top-line data fell short, the Alzheimer’s Association looks forward to a more complete report at upcoming scientific conferences. We learn from every trial,” Maria Carrillo, PhD, chief scientific officer at the Alzheimer’s Association, noted in the organization’s own release.
Rebecca M. Edelmayer, PhD, director of scientific engagement for the Alzheimer’s Association, agreed with Dr. Carrillo that, although the results were disappointing, the data will be beneficial for the field.
“It’s always a difficult day when we get news like this,” Dr. Edelmayer said in an interview. However, “this research is going to absolutely provide valuable information once we can really pick through all of the data.”
Dominantly inherited AD, also known as familial AD or autosomal dominant AD, is rare but can affect memory and cognitive skills in individuals as young as age 30. It is caused by mutations on chromosomes 21, 14, and/or 1 that play a part in the breakdown of amyloid proteins and formation of amyloid plaques.
Both gantenerumab and solanezumab were created to target and neutralize amyloid-beta, albeit through different mechanisms. Both are also being assessed in other trials as treatment for more common forms of AD.
As reported by Medscape Medical News, results of the phase 3 EXPEDITION3 trial of solanezumab in patients with mild AD were negative, as were two other phase 3 trials. The drug is now being evaluated in the ongoing solanezumab Anti-Amyloid Treatment in Asymptomatic Alzheimer’s (A4) study.
Although the phase 3 SCARLET ROAD trial of gantenerumab for mild AD was stopped early for futility in 2014, it was continued as an open-label extension at the high dose for 2 years. During that period, follow-up analyses showed a dramatic decline in amyloid-beta deposition in the participants – leading to the launch of the phase 3 GRADUATE 1 and GRADUATE 2 trials.
Starting in 2012, DIAN-TU was conducted at 24 sites in the United States, the United Kingdom, Canada, Europe, and Australia. It followed 194 adult patients for up to 7 years (average duration, 5 years). Its original estimated completion date was December 2020, as stated on clinicaltrials.gov.
All participants had family members with a genetic mutation that causes early-onset Alzheimer’s disease. They already had very mild symptoms of cognitive decline and memory loss at the start of the trial or were expected to develop symptoms within 15 years of enrollment.
“People who inherit the mutation are all but guaranteed to develop symptoms at about the same age their parents did,” the release noted.
“While devastating for families, such mutations allow researchers to identify people in the early stages of the disease before their behavior and memory begin to change,” it added.
The Alzheimer’s Association noted in its release that a child of a parent with the mutation has a 50/50 chance of inheriting the disease. “This form affects less than 1% of the individuals living with Alzheimer’s disease today,” Dr. Edelmayer noted.