Gantenerumab is an antibody that binds to tangles of amyloid-beta, a protein that forms between brain cells in people who have Alzheimer’s disease. By clearing amyloid from the brain, the drug possibly slows progression of the illness and offers relief from symptoms including memory loss. Gantenerumab is not yet available to the public, but clinical trials are in Phase 3 (see below).
Another amyloid-targeting drug called Aducanumab (brand name Aduhelm) was recently approved by the FDA and can be administered in doctor’s offices. A big difference between Gantenerumab and Aducanumab is that Gantenerumab is an injection that someone can give themselves at home, whereas Aducanumab can only be delivered as an infusion.
Gantenerumab is made by the company Roche and its U.S. wing Genentech.
In late 2021, Gantenerumab received the “Breakthrough Therapy” designation from the FDA, which is meant to make the process of development and review move more quickly.
Amyloid-beta proteins occur naturally in healthy brains, but they tangle and form plaques in the brains of people who have Alzheimer’s disease and some related dementias. Those plaques affect how neurons (brain cells) communicate, and are a likely cause of the symptoms associated with Alzheimer’s disease and related dementias, including memory loss, confusion, and aggression.
Gantenerumab is an antibody, which means it seeks out and sticks to a specific type of protein, in this case amyloid-beta, and then triggers an immune-system response that attacks amyloid and clears it from the brain.
In trials, PET scans showed that the amount of amyloid-beta was reduced in the brains of people with early-stage or mild Alzheimer’s disease.
Gantenerumab is administered via injection, which is different from a similar new drug called Aduhelm that must enter the body intravenously, meaning by infusion in a doctor’s office. Two other amyloid-targeting drugs called Lecanemab and Donanemab (see box above) are also administered intravenously. This means Gantenerumab would be more convenient because the shot could be taken at home.
Two other types of pharmaceuticals that have been prescribed to people with Alzheimer’s, and related dementias including vascular and Lewy body dementias, are cholinesterase inhibitors and memantine. Cholinesterase inhibitors increase levels of a chemical in the brain called acetylcholine, which helps brain cells communicate. Memantine also increases communication ability between cells, by preventing the mutation of a chemical called glutamate.
Gantenerumab previously failed a Phase 3 trial in 2014 after positive results weren’t shown in participants, but it resumed with a higher dose. The higher dose (1,020 milligrams once per month) was shown in PET scans to clear amyloid the way drugmakers had hoped.
Phase 3 is the final stage of testing, when thousands of participants are tested, and there is placebo control to compare the drug against a fake medicine with no effect.
Trials are ongoing through 2023, with more than 2,000 participants. If you are interested in taking part, click here for information and contacts.
If all goes well, the drug would hit the market in 2024.
A potential downside is the possibility for amyloid-related imaging abnormalities (ARIAs) which have been observed in some participants in the early stages of trials. ARIAs have been a concern with other amyloid-targeting drugs as well, and can cause lightheadedness, confusion, nausea, tremors, and other problems.
How much Gantenerumab will cost if it becomes a prescribable drug is not yet known. The drugmaker Roche has said it believes the cost will be “reasonable,” which would be another difference between it and the recently FDA-approved amyloid Alzheimer’s drug aducanumab (brand name Aduhelm) which runs roughly $56,000 per year.
The easier method of taking Gantenerumab, via a shot at home rather than an infusion in a doctor’s office, is one reason it might be more affordable.
Whether Gantenerumab would be covered by Medicaid, Medicare and/or private insurers will not be known until it receives FDA approval.