My Alzheimer's Journey

Part 63 - Lecanemab vs. Donanemab

Today, I received my seventh infusion of Lecanemab. In the space next to me was a woman receiving her first infusion of Donanemab. (the infusion chairs are separated by curtains for visual privacy; however, there is no voice privacy).

After a three-hour nap when I arrived at home after my infusion, I became curious about the difference between Lecanemab and Donanemab. Before I started my infusions, I learned a bit about the differences of these two medications. At that point, I was a newbie to the world of Alzheimer’s. I recall writing in an early blog post that I was “scared shitless.” Fast-forward three and a half months and I consider myself a well-informed, untrained, amateur Alzheimer’s patient and seeker of information. In other words, I know a thing or two about Alzheimer’s disease.

Let’s take a moderately deep dive into Lecanemab and Donanemab.

The differences between Lecanemab and Donanemab include:

Target:

• Lecanemab targets amyloid as it forms fibers

• Donanemab targets existing, larger amyloid

Infusion Frequency & Duration:

• Lecanemab requires an infusion every two weeks for at least eighteen months

• Donanemab requires an infusion every four weeks for an undetermined period (until a significant level of amyloid clearance is reached)

Side Effects:

• Lecanemab reported brain swelling in about 12% of patients on clinical trials and bleeding in about 17% of patients during clinical trials

• Donanemab showed about 37% of patients having brain swelling and bleeding during clinical trials (the greatest risk is for patients with two copies of the ApoE4 gene)

Goal:

• Both drugs have a goal of slowing cognitive decline in early-stage Alzheimer’s by targeting amyloid

Administration:

• Both drugs are IV infusions

Efficacy:

• clinical trial data shows comparable effectiveness in slowing cognitive decline

The BIG difference is that Lecanemab targets early amyloid fibers, while Donanemab targets established plaques.

In theory, Donanemab treatment can be stopped once amyloid is cleared.

Lecanemab was approved by the FDA on July 6, 2023. Donanemab was approved on July 2, 2024.

The clinical trails showed that patients treated with either drug had less amyloid in their brains compared to those who received a placebo. Yet, both drug groups experienced a decline in thinking. But the decline was less severe for those taking either drug as compared to the placebo group.

These drugs are intended for people with mild Alzheimer’s disease, especially those with mild cognitive impairment (MCI). In fact, patients with moderate or severe dementia are not eligible for Lecanemab and Donanemab.

As I mentioned above, the risks for these drugs are significant. Brain swelling and bleeding are certainly concerning. These side effects are more likely to occur within the first fourteen weeks of treatment. I had three MRI scans in my first twelve weeks of receiving Lecanemab infusions. These scans showed no brain swelling or bleeding.

Infusion-related reactions can occur in about 20% of people taking Lecanemab and almost 10% of people taking Donanemab. Typically, these reactions occurred during the infusion or soon afterward. Additionally, these reactions only occurred during the first few infusions. The symptoms of these reactions can include:

• Fever and flu-like symptoms

• Chills

• Nausea

• Headache

• Blood pressure fluctuations

I experienced severe chills, nausea, and headaches after my first four infusions. For me, the reaction symptoms did not appear until several hours after the infusion.

The ideal candidate for these drugs are patients who:

• are aged 50 - 90 years

• are able to have frequent MRI scans

• have mild cognitive impairment or mild dementia due to Alzheimer’s disease

• have confirmed amyloid in their brain

• have a support person for frequent hospital visits

• undergo genetic testing for the ApoE gene

I check all the boxes, so either drug was recommended.

Selecting which drug is best for you is not an easy decision. My medical team said I qualified for either Lecanemab or Donanemab. I made the decision to take Lecanemab because in clinical trials, it excels at removing amyloid, and it has a lower risk of brain swelling and brain bleeding.

My hope is Lecanemab will slow the progression of my Alzheimer’s disease until a better treatment or a cure is developed.

For the next fifteen months, you will find me at the Duke Specialty Infusion Clinic every other Tuesday morning. If it were not for the awesome team of Duke nurses, this ritual would be a huge pain in the ass. As it is, it is just an inconvenience that I have to do to help battle the horrible disease known as Alzheimer’s.