Therapeutics

Donanemab

Overview

Name: Donanemab
Synonyms: N3pG-Aβ Monoclonal Antibody, LY3002813
Therapy Type: Immunotherapy (passive) (timeline)
Target Type: Amyloid-Related (timeline)
Condition(s): Alzheimer's Disease
U.S. FDA Status: Alzheimer's Disease (Phase 2)
Company: Eli Lilly & Co.

Background

Donanemab aka N3pG is a humanized IgG1 monoclonal antibody developed from mouse mE8-IgG2a. This biologic drug recognizes Aβ(p3-42), a pyroglutamate form of Aβ that is aggregated in amyloid plaques. Most Aβ antibodies in therapeutic development bind various soluble or insoluble species but have low affinity to deposited amyloid plaques. The rationale behind donanemab is that targeting deposited plaque itself is necessary to clear existing amyloid burden from the brain, rather than merely prevent deposition of new plaques or growth of existing plaques. Some previous plaque-binding antibodies have been abandoned because they caused microhemorrhages in the brain. The mE8 antibody was reported to clear plaques in mice without causing microhemorrhages (Demattos et al., 2012). 

At the 2014 AAIC conference, Lilly reported that a randomized preclinical study of combination therapy with N3pG and the BACE inhibitor LY2811376 cleared more than 80 percent of amyloid from the brains of PDAPP-transgenic mice, compared to about 50 percent clearance each for the respective monotherapies. Neuropathology studies showed that donanemab removed both cored and diffuse plaques (see Jul 2014 conference news).

Findings

In May 2013 to August 2016, Lilly ran a Phase 1 study in 100 people with mild cognitive impairment due to Alzheimer's disease, or mild Alzheimer's disease, in the U.S. and Japan. Participants had to have a positive amyloid PET scan. This seven-arm study evaluated five intravenous doses from 0.1 mg/kg to 10 mg/kg, infused monthly up to four times, and a single subcutaneous injection against placebo for safety, pharmacokinetics, and pharmacodynamics. At the 2016 AAIC conference in Toronto, Lilly presented results from 49 patients, average age 74, who had completed the trial. Thirty-seven volunteers received a single initial dose, 12 placebo. After adverse event monitoring, they received up to four additional monthly infusions of the same dose; people in the 0.1mg/kg cohort subsequently received 0.3mg/kg. The highest dose was reported to reduce plaque load in the brain, though that group had but six participants. Overall, their mean florbetapir SUVR fell from 1.65 at baseline by 0.26 over seven months, corresponding to a 40 percent reduction. No cases of ARIA were seen in this small trial, but there were two asymptomatic cases of ARIA-H. The antibody was reported to be strongly immunogenic. In the multiple-dose phase, six of the 37 patients had an infusion reaction with chills, flushing, dizziness, rash, and fever, and anti-drug antibodies in plasma (see Aug 2016 conference newsIrizarry et al. 2016).

In December 2015, Lilly started a second Phase 1 study in 150 people with the same diagnosis, again in the U.S. and Japan. This trial has three dosing regimens. The first consists of a single dose of 10, 20, or 40 mg/kg, the second of 10 mg/kg every other week for 24 weeks, and the third of 10 or 20 mg/kg every month for 16 months. Participants are randomized 3:1 to drug or placebo. The study measures primarily donanemab's effect on brain amyloid load with florbetapir PET; secondary outcomes include blood pharmacokinetics of donanemab and auto-antibodies directed against this biologic drug. At the 2018 AAIC, Lilly reported that a six month course of 20 mg/kg dropped amyloid load by an average of 70 centiloid, with three of the six people who had reached that timepoint falling below the threshold for amyloid positivity. About one in four participants developed ARIA-E, mostly asymptomatic. Nearly all patients made anti-drug antibodies, and one had an infusion reaction (Aug 2018 conference news). The trial is set to run until September 2019.

In December 2017, Lilly began TRAILBLAZER, a combination trial of two investigational drugs targeting different points in the amyloid cascade. This phase 2 study was to evaluate safety, tolerability and efficacy of an 18-month course of donanemab alone and in combination with Lilly's BACE inhibitor LY3202626. It aimed to enroll 375 participants whose memory has been worsening for at least 6 months, who meet a cutoff on the CogState Brief Battery, and who have a positive flortaucipir PET scan of between 1.15 to 1.36 SUVR. Within this range, people have detectable cognitive decline over one to two years, but are not yet at advanced disease stages. Because the antibody requires an infusion and the BACE inhibitor comes as a capsule, the three treatment arms in this blinded, placebo-controlled trial were as follows: One group received intravenous donanemab plus placebo administered orally, the second group received intravenous donanemab plus LY3202626 orally, the third group to receive both intravenous and oral placebo. Hence the trial was to evaluate the antibody alone and in combination with the BACE inhibitor, but not the BACE inhibitor alone. The primary outcome is change on the Integrated Alzheimer's Disease Rating Scale (iADRS), a combined cognitive/functional measure for early stage AD developed by Lilly (Wessels et al., 2015). Secondary measures include the ADAS-Cog13, CDR-Sum of Boxes, MMSE, ADCS-iADL, as well as amyloid and tau PET and volumetric MRI. To ease the logistical burden of trial participation, this study offers rides to and from study sites via a partnership between GAP and the ridesharing company Lyft (see press release). The study started up at 63 sites in North America and is set to run until October 2020 (Irizarry et al., 2018).

In October 2018, Lilly discontinued the BACE inhibitor arm of this trial; evaluation of donanemab remains ongoing, with a revised enrollment estimate of 266 participants.

For all trials of this antibody, see clinicaltrials.gov.

Clinical Trial Timeline

  • Phase 2
  • Study completed / Planned end date
  • Planned end date unavailable
  • Study aborted
Sponsor Clinical Trial 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029
Eli Lilly & Co. NCT03367403
N=266

Last Updated: 14 Feb 2019

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References

News Citations

  1. New Ways to Target Aβ and BACE Show Promising Phase 1 Data
  2. Four Immunotherapies Now Banish Amyloid From the Brain
  3. Anti-Amyloid Therapies Combine Forces to Knock Out Plaques

Paper Citations

  1. . A Combined Measure of Cognition and Function for Clinical Trials: The Integrated Alzheimer's Disease Rating Scale (iADRS). J Prev Alzheimers Dis. 2015 Dec 1;2(4):227-241. PubMed.
  2. . A plaque-specific antibody clears existing β-amyloid plaques in Alzheimer's disease mice. Neuron. 2012 Dec 6;76(5):908-20. PubMed.

Other Citations

  1. LY3202626

External Citations

  1. Irizarry et al. 2016
  2. press release
  3. Irizarry et al., 2018
  4. clinicaltrials.gov

Further Reading