Biogen and Eisai Halt Phase 3 Trials Testing Aducanumab for Early Alzheimer’s

José Lopes, PhD avatar

by José Lopes, PhD |

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Two Phase 3 clinical trials testing the investigational therapy aducanumab in patients with early Alzheimer’s disease have been discontinued.

Biogen and Eisai came to this decision after an analysis from an independent data monitoring committee indicated that the global ENGAGE (NCT02477800) and EMERGE (NCT02484547) studies of aducanumab were unlikely to meet their primary objectives. The recommendation to discontinue the trials was not based on safety concerns, according to the companies.

“This disappointing news confirms the complexity of treating Alzheimer’s disease and the need to further advance knowledge in neuroscience,” Michel Vounatsos, Biogen’s CEO, said in a press release. “We are incredibly grateful to all the Alzheimer’s disease patients, their families and the investigators who participated in the trials and contributed greatly to this research.”

Vounatsos also said that Biogen will continue advancing its pipeline of treatment candidates in Alzheimer’s and other diseases of high unmet need.

The two trials were evaluating the efficacy and safety of two doses of aducanumab in people with mild cognitive impairment due to Alzheimer’s and mild Alzheimer’s dementia.

The primary objective of the randomized and double-blind trials was to compare the efficacy of monthly doses of aducanumab — delivered by intravenous (into-the-vein) infusion — with a placebo in slowing cognitive and functional impairment, as assessed via the Clinical Dementia Rating-Sum of Boxes score.

Secondary goals were to compare aducanumab to placebo on clinical progression, as evaluated by Mini-Mental State Examination, the Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-Cog 13), and the Alzheimer’s Disease Cooperative Study-Activities of Daily Living Inventory (ADCS-ADL-MCI).

Detailed findings from ENGAGE and EMERGE will be presented at future medical meetings. In early 2018, Biogen announced it would recruit 510 more patients for the two trials due to greater variability in the results than initially estimated.

Aducanumab is an antibody that preferentially binds to aggregated amyloid beta, a strategy intended to lessen the number of senile plaques in the brain.

As part of the decision to halt the Phase 3 studies, both the EVOLVE Phase 2 trial (NCT03639987) and the long-term extension of the Phase 1b PRIME trial (NCT01677572) of aducanumab will also be discontinued.

Similar to the Phase 3 trials, the Phase 2 study was recruiting patients with mild cognitive impairment due to Alzheimer’s or with mild Alzheimer’s disease dementia to test the safety of aducanumab given every four weeks.

The Phase 1b extension study was evaluating increasing and fixed doses of aducanumab — 1, 3, 6, or 10 mg/kg — in 143 of the patients who started the primary trial, all with early or mild Alzheimer’s disease dementia. Results at up to 48 months of treatment revealed that the investigational therapy effectively reduced the amyloid plaque burden and prevented cognitive decline.

Biogen also announced it will assess the start of the Phase 3 secondary prevention of aducanumab trial while the results of ENGAGE and EMERGE are further evaluated.

The company obtained a license to develop and market aducanumab after reaching an agreement with the therapy’s original developer — Neurimmune — in 2007. Biogen’s partnership with Eisai to advance the clinical development of aducanumab started in October 2017.